A microanalytical technique combining mass spectrometry and gas chromatography for the qualitative as well as quantitative determinations of compounds.
An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.
Fractionation of a vaporized sample as a consequence of partition between a mobile gaseous phase and a stationary phase held in a column. Two types are gas-solid chromatography, where the fixed phase is a solid, and gas-liquid, in which the stationary phase is a nonvolatile liquid supported on an inert solid matrix.
Chromatographic techniques in which the mobile phase is a liquid.
Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.
Organic compounds that have a relatively high VAPOR PRESSURE at room temperature.
A solventless sample preparation method, invented in 1989, that uses a fused silica fiber which is coated with a stationary phase. It is used for sample cleanup before using other analytical methods.
The systematic identification and quantitation of all the metabolic products of a cell, tissue, organ, or organism under varying conditions. The METABOLOME of a cell or organism is a dynamic collection of metabolites which represent its net response to current conditions.
A mass spectrometry technique using two (MS/MS) or more mass analyzers. With two in tandem, the precursor ions are mass-selected by a first mass analyzer, and focused into a collision region where they are then fragmented into product ions which are then characterized by a second mass analyzer. A variety of techniques are used to separate the compounds, ionize them, and introduce them to the first mass analyzer. For example, for in GC-MS/MS, GAS CHROMATOGRAPHY-MASS SPECTROMETRY is involved in separating relatively small compounds by GAS CHROMATOGRAPHY prior to injecting them into an ionization chamber for the mass selection.
The dynamic collection of metabolites which represent a cell's or organism's net metabolic response to current conditions.
A mass spectrometry technique used for analysis of nonvolatile compounds such as proteins and macromolecules. The technique involves preparing electrically charged droplets from analyte molecules dissolved in solvent. The electrically charged droplets enter a vacuum chamber where the solvent is evaporated. Evaporation of solvent reduces the droplet size, thereby increasing the coulombic repulsion within the droplet. As the charged droplets get smaller, the excess charge within them causes them to disintegrate and release analyte molecules. The volatilized analyte molecules are then analyzed by mass spectrometry.
Oils which evaporate readily. The volatile oils occur in aromatic plants, to which they give odor and other characteristics. Most volatile oils consist of a mixture of two or more TERPENES or of a mixture of an eleoptene (the more volatile constituent of a volatile oil) with a stearopten (the more solid constituent). The synonym essential oils refers to the essence of a plant, as its perfume or scent, and not to its indispensability.
A phase transition from liquid state to gas state, which is affected by Raoult's law. It can be accomplished by fractional distillation.
A plant species of the genus OCIMUM, family LAMIACEAE. It is a condiment with carminative properties.
Chromatography on thin layers of adsorbents rather than in columns. The adsorbent can be alumina, silica gel, silicates, charcoals, or cellulose. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Unsaturated androstane derivatives which are substituted with two hydroxy groups in any position in the ring system.
Compounds used extensively as acetylation, oxidation and dehydrating agents and in the modification of proteins and enzymes.
Detection of drugs that have been abused, overused, or misused, including legal and illegal drugs. Urine screening is the usual method of detection.
The thick green-to-black mucilaginous material found in the intestines of a full-term fetus. It consists of secretions of the INTESTINAL GLANDS; BILE PIGMENTS; FATTY ACIDS; AMNIOTIC FLUID; and intrauterine debris. It constitutes the first stools passed by a newborn.
Deuterium. The stable isotope of hydrogen. It has one neutron and one proton in the nucleus.
Illegitimate use of substances for a desired effect in competitive sports. It includes humans and animals.
Isoprostanes derived from the free radical oxidation of ARACHIDONIC ACID. Although similar in structure to enzymatically synthesized prostaglandin F2alpha (DINOPROST), they occur through non-enzymatic oxidation of cell membrane lipids.
Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).
Organic, monobasic acids derived from hydrocarbons by the equivalent of oxidation of a methyl group to an alcohol, aldehyde, and then acid. Fatty acids are saturated and unsaturated (FATTY ACIDS, UNSATURATED). (Grant & Hackh's Chemical Dictionary, 5th ed)
A mass spectrometric technique that is used for the analysis of large biomolecules. Analyte molecules are embedded in an excess matrix of small organic molecules that show a high resonant absorption at the laser wavelength used. The matrix absorbs the laser energy, thus inducing a soft disintegration of the sample-matrix mixture into free (gas phase) matrix and analyte molecules and molecular ions. In general, only molecular ions of the analyte molecules are produced, and almost no fragmentation occurs. This makes the method well suited for molecular weight determinations and mixture analysis.
The chemical alteration of an exogenous substance by or in a biological system. The alteration may inactivate the compound or it may result in the production of an active metabolite of an inactive parent compound. The alterations may be divided into METABOLIC DETOXICATION, PHASE I and METABOLIC DETOXICATION, PHASE II.
Organic compounds containing the carboxy group (-COOH). This group of compounds includes amino acids and fatty acids. Carboxylic acids can be saturated, unsaturated, or aromatic.
Eicosatetraenoic acids substituted in any position by one or more hydroxy groups. They are important intermediates in a series of biosynthetic processes leading from arachidonic acid to a number of biologically active compounds such as prostaglandins, thromboxanes, and leukotrienes.
The vapor state of matter; nonelastic fluids in which the molecules are in free movement and their mean positions far apart. Gases tend to expand indefinitely, to diffuse and mix readily with other gases, to have definite relations of volume, temperature, and pressure, and to condense or liquefy at low temperatures or under sufficient pressure. (Grant & Hackh's Chemical Dictionary, 5th ed)
Examination of urine by chemical, physical, or microscopic means. Routine urinalysis usually includes performing chemical screening tests, determining specific gravity, observing any unusual color or odor, screening for bacteriuria, and examining the sediment microscopically.
The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.
A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).
A system for verifying and maintaining a desired level of quality in a product or process by careful planning, use of proper equipment, continued inspection, and corrective action as required. (Random House Unabridged Dictionary, 2d ed)
A group of polycyclic compounds closely related biochemically to TERPENES. They include cholesterol, numerous hormones, precursors of certain vitamins, bile acids, alcohols (STEROLS), and certain natural drugs and poisons. Steroids have a common nucleus, a fused, reduced 17-carbon atom ring system, cyclopentanoperhydrophenanthrene. Most steroids also have two methyl groups and an aliphatic side-chain attached to the nucleus. (From Hawley's Condensed Chemical Dictionary, 11th ed)
Addition of methyl groups. In histo-chemistry methylation is used to esterify carboxyl groups and remove sulfate groups by treating tissue sections with hot methanol in the presence of hydrochloric acid. (From Stedman, 25th ed)
The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.
The characteristic 3-dimensional shape of a carbohydrate.
Chemical compounds which pollute the water of rivers, streams, lakes, the sea, reservoirs, or other bodies of water.
The sequence of carbohydrates within POLYSACCHARIDES; GLYCOPROTEINS; and GLYCOLIPIDS.
An enzyme of the oxidoreductase class primarily found in PLANTS. It catalyzes reactions between linoleate and other fatty acids and oxygen to form hydroperoxy-fatty acid derivatives.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
A major group of unsaturated cyclic hydrocarbons containing two or more rings. The vast number of compounds of this important group, derived chiefly from petroleum and coal tar, are rather highly reactive and chemically versatile. The name is due to the strong and not unpleasant odor characteristic of most substances of this nature. (From Hawley's Condensed Chemical Dictionary, 12th ed, p96)
The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)
Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)
A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.
The composition, conformation, and properties of atoms and molecules, and their reaction and interaction processes.
An unsaturated, essential fatty acid. It is found in animal and human fat as well as in the liver, brain, and glandular organs, and is a constituent of animal phosphatides. It is formed by the synthesis from dietary linoleic acid and is a precursor in the biosynthesis of prostaglandins, thromboxanes, and leukotrienes.
The process of cleaving a chemical compound by the addition of a molecule of water.
The systematic study of the complete complement of proteins (PROTEOME) of organisms.
A naturally occurring prostaglandin that has oxytocic, luteolytic, and abortifacient activities. Due to its vasocontractile properties, the compound has a variety of other biological actions.
A superfamily of hundreds of closely related HEMEPROTEINS found throughout the phylogenetic spectrum, from animals, plants, fungi, to bacteria. They include numerous complex monooxygenases (MIXED FUNCTION OXYGENASES). In animals, these P-450 enzymes serve two major functions: (1) biosynthesis of steroids, fatty acids, and bile acids; (2) metabolism of endogenous and a wide variety of exogenous substrates, such as toxins and drugs (BIOTRANSFORMATION). They are classified, according to their sequence similarities rather than functions, into CYP gene families (>40% homology) and subfamilies (>59% homology). For example, enzymes from the CYP1, CYP2, and CYP3 gene families are responsible for most drug metabolism.
FATTY ACIDS in which the carbon chain contains one or more double or triple carbon-carbon bonds.
Measurable and quantifiable biological parameters (e.g., specific enzyme concentration, specific hormone concentration, specific gene phenotype distribution in a population, presence of biological substances) which serve as indices for health- and physiology-related assessments, such as disease risk, psychiatric disorders, environmental exposure and its effects, disease diagnosis, metabolic processes, substance abuse, pregnancy, cell line development, epidemiologic studies, etc.
A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.
Six-carbon saturated hydrocarbon group of the methane series. Include isomers and derivatives. Various polyneuropathies are caused by hexane poisoning.
A chromatographic technique that utilizes the ability of biological molecules to bind to certain ligands specifically and reversibly. It is used in protein biochemistry. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Elements of limited time intervals, contributing to particular results or situations.
Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.
Separation technique in which the stationary phase consists of ion exchange resins. The resins contain loosely held small ions that easily exchange places with other small ions of like charge present in solutions washed over the resins.
The rate dynamics in chemical or physical systems.
A plant family of the order Eucommiales, subclass Hamamelidae, class Magnoliopsida (some botanists have classified this in the order Hamamelidales or Urticales). Eucomia is an elmlike tree of central and eastern China. Leaves are alternate; deciduous flowers are solitary and unisexual and lack petals and sepals. The male flowers have 6 to 10 stamens and female flowers have one ovary of two carpels, one of which aborts during development so the fruit (a dry, winged structure) contains only one seed. The latex is a source of RUBBER. Tochu tea is an aqueous extract of Eucommia ulmoides leaves and a popular beverage in Japan. (Mutat Res 1997 Jan 15;388(1):7-20).
Determination, by measurement or comparison with a standard, of the correct value of each scale reading on a meter or other measuring instrument; or determination of the settings of a control device that correspond to particular values of voltage, current, frequency or other output.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
Physiological processes in biosynthesis (anabolism) and degradation (catabolism) of LIPIDS.
Techniques for labeling a substance with a stable or radioactive isotope. It is not used for articles involving labeled substances unless the methods of labeling are substantively discussed. Tracers that may be labeled include chemical substances, cells, or microorganisms.
Five-carbon saturated hydrocarbon group of the methane series. Include isomers and derivatives.
Techniques used to separate mixtures of substances based on differences in the relative affinities of the substances for mobile and stationary phases. A mobile phase (fluid or gas) passes through a column containing a stationary phase of porous solid or liquid coated on a solid support. Usage is both analytical for small amounts and preparative for bulk amounts.
A 20-carbon-chain fatty acid, unsaturated at positions 8, 11, and 14. It differs from arachidonic acid, 5,8,11,14-eicosatetraenoic acid, only at position 5.
A basis of value established for the measure of quantity, weight, extent or quality, e.g. weight standards, standard solutions, methods, techniques, and procedures used in diagnosis and therapy.
The protein complement of an organism coded for by its genome.
Concentration or quantity that is derived from the smallest measure that can be detected with reasonable certainty for a given analytical procedure.
Chromatography on non-ionic gels without regard to the mechanism of solute discrimination.
A plant genus of the family CRASSULACEAE. Members contain rhodioloside. This roseroot is unrelated to the familiar rose (ROSA). Some species in this genus are called stonecrop which is also a common name for SEDUM.
Any tests done on exhaled air.
The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.
Substances or organisms which pollute the water or bodies of water. Use for water pollutants in general or those for which there is no specific heading.
Pyrolysis of organic compounds at the temperature of a hydrogen-air flame to produce ionic intermediates which can be collected and the resulting ion current measured by gas chromatography.
Unstable isotopes of carbon that decay or disintegrate emitting radiation. C atoms with atomic weights 10, 11, and 14-16 are radioactive carbon isotopes.
Stable carbon atoms that have the same atomic number as the element carbon, but differ in atomic weight. C-13 is a stable carbon isotope.
A chromatography technique in which the stationary phase is composed of a non-polar substance with a polar mobile phase, in contrast to normal-phase chromatography in which the stationary phase is a polar substance with a non-polar mobile phase.
A colorless, flammable liquid used in the manufacture of FORMALDEHYDE and ACETIC ACID, in chemical synthesis, antifreeze, and as a solvent. Ingestion of methanol is toxic and may cause blindness.
A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement.
The relationship between the dose of an administered drug and the response of the organism to the drug.
The monitoring of the level of toxins, chemical pollutants, microbial contaminants, or other harmful substances in the environment (soil, air, and water), workplace, or in the bodies of people and animals present in that environment.
The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.
Carbohydrates consisting of between two (DISACCHARIDES) and ten MONOSACCHARIDES connected by either an alpha- or beta-glycosidic link. They are found throughout nature in both the free and bound form.
Polyhydric alcohols having no more than one hydroxy group attached to each carbon atom. They are formed by the reduction of the carbonyl group of a sugar to a hydroxyl group.(From Dorland, 28th ed)
A disturbance in the prooxidant-antioxidant balance in favor of the former, leading to potential damage. Indicators of oxidative stress include damaged DNA bases, protein oxidation products, and lipid peroxidation products (Sies, Oxidative Stress, 1991, pxv-xvi).
Derivatives of ACETIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the carboxymethane structure.
Closed vesicles of fragmented endoplasmic reticulum created when liver cells or tissue are disrupted by homogenization. They may be smooth or rough.
Inorganic or organic compounds that contain sulfur as an integral part of the molecule.
Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.
Chemicals that kill or inhibit the growth of fungi in agricultural applications, on wood, plastics, or other materials, in swimming pools, etc.
Compounds consisting of benzene rings linked to each other in either ortho, meta or para positions. Permitted are any substitutions, but ring fusion to any of the benzene rings is not allowed.
An extraction method that separates analytes using a solid phase and a liquid phase. It is used for preparative sample cleanup before analysis by CHROMATOGRAPHY and other analytical methods.
Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.
Electrophoresis in which a second perpendicular electrophoretic transport is performed on the separate components resulting from the first electrophoresis. This technique is usually performed on polyacrylamide gels.
Methods for assessing flow through a system by injection of a known quantity of an indicator, such as a dye, radionuclide, or chilled liquid, into the system and monitoring its concentration over time at a specific point in the system. (From Dorland, 28th ed)
A mass-spectrometric technique that is used for microscopic chemical analysis. A beam of primary ions with an energy of 5-20 kiloelectronvolts (keV) bombards a small spot on the surface of the sample under ultra-high vacuum conditions. Positive and negative secondary ions sputtered from the surface are analyzed in a mass spectrometer in regards to their mass-to-charge ratio. Digital imaging can be generated from the secondary ion beams and their intensity can be measured. Ionic images can be correlated with images from light or other microscopy providing useful tools in the study of molecular and drug actions.
Atomic species differing in mass number but having the same atomic number. (Grant & Hackh's Chemical Dictionary, 5th ed)
The sum of the weight of all the atoms in a molecule.
Pesticides or their breakdown products remaining in the environment following their normal use or accidental contamination.
An emulsifying agent produced in the LIVER and secreted into the DUODENUM. Its composition includes BILE ACIDS AND SALTS; CHOLESTEROL; and ELECTROLYTES. It aids DIGESTION of fats in the duodenum.
A mass spectrometric technique that is used for the analysis of a wide range of biomolecules, such as glycoalkaloids, glycoproteins, polysaccharides, and peptides. Positive and negative fast atom bombardment spectra are recorded on a mass spectrometer fitted with an atom gun with xenon as the customary beam. The mass spectra obtained contain molecular weight recognition as well as sequence information.
Determination of the spectra of ultraviolet absorption by specific molecules in gases or liquids, for example Cl2, SO2, NO2, CS2, ozone, mercury vapor, and various unsaturated compounds. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.
Concentrated pharmaceutical preparations of plants obtained by removing active constituents with a suitable solvent, which is evaporated away, and adjusting the residue to a prescribed standard.
Glycosides of GLUCURONIC ACID formed by the reaction of URIDINE DIPHOSPHATE GLUCURONIC ACID with certain endogenous and exogenous substances. Their formation is important for the detoxification of drugs, steroid excretion and BILIRUBIN metabolism to a more water-soluble compound that can be eliminated in the URINE and BILE.
An atom or group of atoms that have a positive or negative electric charge due to a gain (negative charge) or loss (positive charge) of one or more electrons. Atoms with a positive charge are known as CATIONS; those with a negative charge are ANIONS.
Benzene derivatives that include one or more hydroxyl groups attached to the ring structure.
Placing of a hydroxyl group on a compound in a position where one did not exist before. (Stedman, 26th ed)
Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.
Oligosaccharides containing two monosaccharide units linked by a glycosidic bond.
Drugs intended for human or veterinary use, presented in their finished dosage form. Included here are materials used in the preparation and/or formulation of the finished dosage form.
A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.
The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Substances used for the detection, identification, analysis, etc. of chemical, biological, or pathologic processes or conditions. Indicators are substances that change in physical appearance, e.g., color, at or approaching the endpoint of a chemical titration, e.g., on the passage between acidity and alkalinity. Reagents are substances used for the detection or determination of another substance by chemical or microscopical means, especially analysis. Types of reagents are precipitants, solvents, oxidizers, reducers, fluxes, and colorimetric reagents. (From Grant & Hackh's Chemical Dictionary, 5th ed, p301, p499)
Changes in the amounts of various chemicals (neurotransmitters, receptors, enzymes, and other metabolites) specific to the area of the central nervous system contained within the head. These are monitored over time, during sensory stimulation, or under different disease states.
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
A generic term for fats and lipoids, the alcohol-ether-soluble constituents of protoplasm, which are insoluble in water. They comprise the fats, fatty oils, essential oils, waxes, phospholipids, glycolipids, sulfolipids, aminolipids, chromolipids (lipochromes), and fatty acids. (Grant & Hackh's Chemical Dictionary, 5th ed)
A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.
Substances or energies, for example heat or light, which when introduced into the air, water, or land threaten life or health of individuals or ECOSYSTEMS.
Analysis of PEPTIDES that are generated from the digestion or fragmentation of a protein or mixture of PROTEINS, by ELECTROPHORESIS; CHROMATOGRAPHY; or MASS SPECTROMETRY. The resulting peptide fingerprints are analyzed for a variety of purposes including the identification of the proteins in a sample, GENETIC POLYMORPHISMS, patterns of gene expression, and patterns diagnostic for diseases.
A group of compounds derived from ammonia by substituting organic radicals for the hydrogens. (From Grant & Hackh's Chemical Dictionary, 5th ed)
The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.
Proteins prepared by recombinant DNA technology.
The development and use of techniques and equipment to study or perform chemical reactions, with small quantities of materials, frequently less than a milligram or a milliliter.
Studies which start with the identification of persons with a disease of interest and a control (comparison, referent) group without the disease. The relationship of an attribute to the disease is examined by comparing diseased and non-diseased persons with regard to the frequency or levels of the attribute in each group.
The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.
The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.
Organic compounds containing the -CO-NH2 radical. Amides are derived from acids by replacement of -OH by -NH2 or from ammonia by the replacement of H by an acyl group. (From Grant & Hackh's Chemical Dictionary, 5th ed)
Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.
Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.
Separation of a mixture in successive stages, each stage removing from the mixture some proportion of one of the substances, for example by differential solubility in water-solvent mixtures. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Widely distributed enzymes that carry out oxidation-reduction reactions in which one atom of the oxygen molecule is incorporated into the organic substrate; the other oxygen atom is reduced and combined with hydrogen ions to form water. They are also known as monooxygenases or hydroxylases. These reactions require two substrates as reductants for each of the two oxygen atoms. There are different classes of monooxygenases depending on the type of hydrogen-providing cosubstrate (COENZYMES) required in the mixed-function oxidation.
Fatty acid derivatives that have specificity for CANNABINOID RECEPTORS. They are structurally distinct from CANNABINOIDS and were originally discovered as a group of endogenous CANNABINOID RECEPTOR AGONISTS.
Proteins found in any species of bacterium.
The giving of drugs, chemicals, or other substances by mouth.
A statistical means of summarizing information from a series of measurements on one individual. It is frequently used in clinical pharmacology where the AUC from serum levels can be interpreted as the total uptake of whatever has been administered. As a plot of the concentration of a drug against time, after a single dose of medicine, producing a standard shape curve, it is a means of comparing the bioavailability of the same drug made by different companies. (From Winslade, Dictionary of Clinical Research, 1992)
Accumulation of a drug or chemical substance in various organs (including those not relevant to its pharmacologic or therapeutic action). This distribution depends on the blood flow or perfusion rate of the organ, the ability of the drug to penetrate organ membranes, tissue specificity, protein binding. The distribution is usually expressed as tissue to plasma ratios.
The application of medical knowledge to questions of law.
Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).
A cytochrome P-450 suptype that has specificity for a broad variety of lipophilic compounds, including STEROIDS; FATTY ACIDS; and XENOBIOTICS. This enzyme has clinical significance due to its ability to metabolize a diverse array of clinically important drugs such as CYCLOSPORINE; VERAPAMIL; and MIDAZOLAM. This enzyme also catalyzes the N-demethylation of ERYTHROMYCIN.
Sequential operating programs and data which instruct the functioning of a digital computer.
A research technique to measure solvent exposed regions of molecules that is used to provide insight about PROTEIN CONFORMATION.
Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.
A large group of cytochrome P-450 (heme-thiolate) monooxygenases that complex with NAD(P)H-FLAVIN OXIDOREDUCTASE in numerous mixed-function oxidations of aromatic compounds. They catalyze hydroxylation of a broad spectrum of substrates and are important in the metabolism of steroids, drugs, and toxins such as PHENOBARBITAL, carcinogens, and insecticides.
Amides composed of unsaturated aliphatic FATTY ACIDS linked with AMINES by an amide bond. They are most prominent in ASTERACEAE; PIPERACEAE; and RUTACEAE; and also found in ARISTOLOCHIACEAE; BRASSICACEAE; CONVOLVULACEAE; EUPHORBIACEAE; MENISPERMACEAE; POACEAE; and SOLANACEAE. They are recognized by their pungent taste and for causing numbing and salivation.

Analysis of gabapentin in serum and plasma by solid-phase extraction and gas chromatography-mass spectrometry for therapeutic drug monitoring. (1/5623)

A simple method for the determination of gabapentin (Neurontin) is described. The method uses solid-phase extraction by disk column and derivatization followed by gas chromatographic-mass spectrometric analysis. The single-step derivatization with MTBSTFA produces a t-BDMS derivative of both the carboxylic and amine moieties of the molecule. Each step of the procedure was optimized to assure reliable performance of the method. The assay limit of detection was 0.1 microg/mL with a linear range from 1.0 to 35 microg/mL. Within-run (n = 3) and between-run (n = 40) coefficients of variation were less than 8.2 and 15.9%, respectively. The method has proven reliable in routine production for more than a year, producing clean chromatography with unique ion fragments, consistent ion mass ratios, and no interferences. Statistical analysis of the gabapentin concentrations measured in 1020 random specimens over a 2-month period showed a mean concentration of 6.07 microg/mL with a standard deviation of 5.28.  (+info)

Solid-phase microextraction for cannabinoids analysis in hair and its possible application to other drugs. (2/5623)

This paper describes the application of solid-phase microextraction (SPME) to cannabis testing in hair. Fifty milligrams of hair was washed with petroleum ether, hydrolyzed with NaOH, neutralized, deuterated internal standard was added and directly submitted to SPME. The SPME was analyzed by GC-MS. The limit of detection was 0.1 ng/mg for cannabinol (CBN) and delta9-tetrahydrocannabinol (THC) and 0.2 ng/mg for cannabidiol (CBD). THC was detected in a range spanning from 0.1 to 0.7 ng/mg. CBD concentrations ranged from 0.7 to 14.1 ng/mg, and CBN concentrations ranged from 0.4 to 0.7 ng/mg. The effectiveness of different decontamination procedures was also studied on passively contaminated hair. The proposed method is also suitable for the analysis of methadone in hair; cocaine and cocaethylene can be detected in hair with SPME extraction after enzymatic hydrolysis.  (+info)

Highly sensitive quantitation of methamphetamine by time-resolved fluoroimmunoassay using a new europium chelate as a label. (3/5623)

A simple and highly sensitive time-resolved fluoroimmunoassay of methamphetamine (MA) using a new fluorescent europium chelate (BHHCT-Eu3+) as a label is described. Two variations of competitive immunoassay were attempted. In the first (one-step) assay, microtiter plates coated with anti-MA were used, and the new label was bound to a conjugate of bovine serum albumin and N-(4-aminobutyl)-MA (MA-BSA). In the second (two-step) assay, instead of the labeled MA-BSA, biotinylated MA-BSA and BHHCT-Eu3+-labeled streptavidin-BSA were used. The lowest measurable concentrations of MA for the one-step and the two-step methods were 1 ng/mL (25 pg/assay) and 1 pg/mL (25 fg/assay), respectively. These were 10 to 1000 times superior to the detection limits of MA in any other immunoassay. Intra-assay coefficient of variation was approximately 2-8% at eight different concentrations (n = 4). Analysis of 34 urine samples with the new method and conventional gas chromatography showed a good correlation (r = 0.954). The high detectability of the present assay also enabled segmental hair analysis with a few centimeters of a hair.  (+info)

Cocaine metabolite kinetics in the newborn. (4/5623)

The study goal was to determine the half-life elimination of cocaine and benzoylecgonine (BZE) in the newborn. Three 0.3-mL blood samples were collected during the first day of life. Urine was collected once daily. Cocaine and BZE concentrations were determined by gas chromatography-mass spectrometry. An extraction method was developed for measuring low concentrations of cocaine and BZE in small (0.1 mL) blood samples. Cocaine had a half-life of 11.6 h in one subject. The half-life of BZE during the first day of life, based on blood data in 13 subjects, was 16 h (95% confidence interval [CI], 12.8 to 21.4 h). The half-life of BZE during the first week of life, based on urine data in 16 subjects, was 11.2 h (95% CI, 10.1 to 11.8 h). The novel extraction method for small blood sample volumes should be applicable to other basic drugs.  (+info)

The urinary elimination profiles of diazepam and its metabolites, nordiazepam, temazepam, and oxazepam, in the equine after a 10-mg intramuscular dose. (5/5623)

A method for the extraction of diazepam and its metabolites (nordiazepam, temazepam, and oxazepam) from equine urine and serum and their quantitation and confirmation by liquid chromatography-tandem mass spectrometry is presented. Valium, a formulation of diazepam, was administered at a dose of 10 mg intramuscularly to four standard-bred mares. Diazepam is extensively metabolized in the horse to nordiazepam, temazepam, and oxazepam. Diazepam urinary concentrations were found to be less than 6 ng/mL. Nordiazepam was found to be mainly in its glucuronide-conjugated form and was measured out to a collection time of 53-55 h. Oxazepam and temazepam were entirely conjugated, and their urinary concentrations were measured out to collection times of 121 h and 77-79 h, respectively. Diazepam and nordiazepam were measured in equine postadministration serum out to collection times of 6 and 54 h, respectively. Oxazepam and temazepam were not detected in postadministration serum.  (+info)

Semiautomated preparation of 3,5,6-trichloro-2-pyridinol in human urine using a Zymate XP laboratory robot with quantitative determination by gas chromatography-negative-ion chemical ionization mass spectrometry. (6/5623)

A rapid and sensitive semiautomated method was developed for quantitation of the chlorpyrifos metabolite 3,5,6-trichloro-2-pyridinol (TCP) in human urine. A Zymark Zymate XP laboratory robotics system was used to mix urine samples, transfer aliquots, add the stable-isotope-labeled TCP internal standard (13C2- or 13C2,15N-), and liberate conjugates of TCP from urine via acid hydrolysis. Samples were manually extracted into toluene, derivatized, and analyzed by gas chromatography-negative-ion chemical ionization mass spectrometry. Determination of the metabolic TCP was performed by selected ion monitoring of the dichloropyridinol fragment ions: m/z 161 for TCP and m/z 165 for 13C2-TCP or m/z 168 for 13C2,15N-TCP. Interday precision and accuracy were demonstrated over 3 years of analyses using the 13C2-TCP internal standard, with an average recovery from fortified urine samples of 93+/-12% (N = 54, concentration range 1-140 ng/mL). The method was found to be linear over the range of 0.5 to 200 ng/mL, and the limit of detection for TCP in urine was estimated to be 0.2 ng/mL with a limit of quantitation of 1 ng/mL. The effect of solids distribution on the concentration of TCP in the thawed urine samples was examined, and the results indicated that homogeneous distribution is critical for quantitation. The precision and accuracy of the automated method with respect to the transfer of homgeneous urine aliquots and delivery of internal standard yielded equivalent or improved results over the manual techniques. Overall, this method is more simple than existing methodologies, and it yields results with improved precision, accuracy, and sensitivity over previously developed methods.  (+info)

Determination of pyrolysis products of smoked methamphetamine mixed with tobacco by tandem mass spectrometry. (7/5623)

This study examines the pyrolysis products of smoked methamphetamine mixed with tobacco that was trapped with a C8 adsorbent cartridge and then detected by gas chromatography-tandem mass spectrometry. According to the results, the mainstream smoke contains 2-methylpropyl-benzene, 2-chloropropyl-benzene, 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one, 3-ethyl-phenol, methamphetamine, dimethylamphetamine, hydroquinone, 3-methyl-5-(1-methylethyl)-methylcarbamate phenol, N-methyl-N-(2-phenylethyl)-acetamide, 4-(3-hydroxy-1-butenyl)-3,5,5-trimethyl-2-cyclohexene-1-one, propanoic acid, N-acetylmethamphetamine, phenyl ester, and furfurylmethylamphetamine. In addition, the compounds in sidestream smoke are 2-propenyl benzene, phenylacetone, methamphetamine, dimethylamphetamine, benzyl methyl ketoxime, 3,4-dihydro-2-naphthalenone, N-folmyamphetamine, N-acetylamphetamine, bibenzyl, N-folmylmethamphetamine, N-acetylmethamphetamine, N-propionymethamphetamine, and furfurylmethylamphetamine. Moreover, the presence of methamphetamine promotes the oxidation of the tobacco components.  (+info)

Identification and quantification of cocaine N-oxide: a thermally labile metabolite of cocaine. (8/5623)

In this article, we report the identification and quantitation of cocaine N-oxide (CNO), a thermally labile oxidative metabolite, from both animal and human samples. The concentration of CNO is similar to the concentrations of cocaine in the samples analyzed. The technique used for the determination of CNO in this study is liquid chromatography-electrospray ionization mass spectrometry, which is necessary because CNO is converted to cocaine upon heating. This includes simple heating of aqueous solutions to temperatures in excess of 100 degrees C and analysis by gas chromatography-mass spectrometry (GC-MS), in which CNO is converted to cocaine in the injection port. The thermal conversion of CNO to cocaine is estimated to cause an over-reporting of cocaine levels by 10-20% when using GC-MS.  (+info)

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Gas chromatography mass spectrometry (GC/MS)-based fecal metabonomics represents a powerful systems biology approach for elucidating metabolic biomarkers of lower gastrointestinal tract (GIT) diseases. Unlike metabolic profiling of fecal water, the profiling of complete fecal material remains under-explored. Here, a gas chromatography/time-of-flight mass spectrometry (GC/TOFMS) method was developed and validated for the global metabonomic profiling of human feces. Fecal and fecal water metabotypes were also profiled and compared. Additionally, the unclear influence of blood in stool on the fecal metabotype was investigated unprecedentedly. Eighty milligram of lyophilized feces was ultrasonicated with 1mL of methanol:water (8:2) for 30min, followed by centrifugation, drying of supernatant, oximation and trimethylsilylation for 45min. Lyophilized feces demonstrated a more comprehensive metabolic coverage than fecal water, based on the number of chromatographic peaks. Principal component analysis ...
Abstract. We present the characterization and application of a new gas chromatography time-of-flight mass spectrometry instrument (GC-TOFMS) for the quantitative analysis of halocarbons in air samples. The setup comprises three fundamental enhancements compared to our earlier work (Hoker et al., 2015): (1) full automation, (2) a mass resolving power R = m/Δm of the TOFMS (Tofwerk AG, Switzerland) increased up to 4000 and (3) a fully accessible data format of the mass spectrometric data. Automation in combination with the accessible data allowed an in-depth characterization of the instrument. Mass accuracy was found to be approximately 5 ppm in mean after automatic recalibration of the mass axis in each measurement. A TOFMS configuration giving R = 3500 was chosen to provide an R-to-sensitivity ratio suitable for our purpose. Calculated detection limits are as low as a few femtograms by means of the accurate mass information. The precision for substance quantification was 0.15 % at the best for ...
QP-2010s Gas Chromatograph/Mass Spectrometer from Shimadzu,Shimadzus GCMS-QP2010s Gas Chromatograph/Mass Spectrometer, utilizing many of the high-end features of the GCMS-QP2010 Plus, offers high throughput and excellent productivity, providing users with an excellent performance-to-cost ratio. Like the GCMS-QP2010 Plus, the GCMS-QP2010s features patented,biological,biology supply,biology supplies,biology product
TY - UNPB. T1 - VOCCluster: Untargeted Metabolomics Feature Clustering Approach for Clinical Breath Gas Chromatography-Mass Spectroscopy Data. AU - Alkhalifah, Yaser. AU - Phillips, Iain. AU - Soltoggio, Andrea. AU - Darnley, Kareen. AU - Nailon, William Henry. AU - McLaren, Duncan. AU - Eddleston, Michael. AU - Thomas, Paul AU - Salman, Dahlia. PY - 2019/2/18. Y1 - 2019/2/18. M3 - Working paper. T3 - ChemRxiv. BT - VOCCluster: Untargeted Metabolomics Feature Clustering Approach for Clinical Breath Gas Chromatography-Mass Spectroscopy Data. ER - ...
The Canadian Forest Service promotes the sustainable development of Canadas forests and the competitiveness of the Canadian forest sector
Comprehensive two-dimensional gas chromatography (GC×GC) is a high resolution and high sensitivity technique. It is especially suitable for the separation and identification of analytes in complex mixtures. Focused on the characterization of complex mixtures, a series of method and application studies using GC×GC have been carried out. Although comprehensive two-dimensional gas chromatography (GC×GC) can offer high resolution and sensitivity compared with traditional one-dimensional gas chromatography (1DGC), sample preparation is still essential for trace component analysis. An on-column cold trap device was used as a part of GC×GC or GC×GC combined with time-of-flight mass spectrometry (TOFMS) systems. The on-column cold trap device using a homemade double layer CO2 jet was mounted on the GC×GC or GC×GC-TOFMS, and performed at -60 ℃-70 cryogenic ℃temperature. Based on large volume injection, the trace compounds were focused at the head of column by cold trap and stationary phase, ...
TY - JOUR. T1 - Principles and applications of comprehensive two-dimensional gas chromatography. AU - Marriott, Philip. AU - Shellie, Robert. PY - 2002/1/1. Y1 - 2002/1/1. N2 - This issue of Trends in Analytical Chemistry celebrates 50 years of gas chromatography (GC) - the greatest enabling technology for chemical analysis of volatile compounds. However, what may be considered the most powerful separation tool in GC - comprehensive two-dimensional gas chromatography (GC×GC) - is a development born of the 1990s. It was first described and almost fully established in the last decade of the twentieth century. The coming decades can be expected to see it flourish into a major operating mode of GC, when applications and fundamental principles will be further expanded, and, most importantly, its universal acceptance will be unquestioned. This article describes why the pioneers of GC×GC have so much faith in the new opportunities afforded by this exciting technology.. AB - This issue of Trends in ...
A sensitive and specific assay for the quantitative determination of amphetamine, methamphetamine and desmethyldeprenyl in human plasma specimens is described. Electron capture/negative ion chemical ionization gas chromatography/mass spectrometry is used to determine the extracted plasma concentrati...
The composition and changes of the fungal population and of the metabolites present in grapes and in ferments of Vitis vinifera L. cv. Corvina, one of the major components of the Amarone musts, were dissected aiming at the identification of constant characteristics possibly influenced by the productive process. The fungal populations and metabolomic profiles were analyzed in three different vintages. 454-pyrosequencing on the ribosomal ITS1 region has been used to identify the fungal population present in Corvina grapes and fresh must. Samples were also subjected to metabolomics analysis measuring both free volatile compounds and glycosylated aroma precursors through an untargeted approach with comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry. Albeit strongly dependent on the climate, both the mycobiota and metabolome of Corvina grapes and fresh musts show some characteristics recursive in different vintages. Such persistent characteristics are likely determined ...
Qiu YQ,Lu X,Pang T,et al. Study of traditional Chinese medicine volatile oils from different geographical origins by comprehensive two-dimensional gas chromatography - time-of-flight mass spectrometry (GC×GC-TOFMS) in combination with multivariate analysis[J]. Journal of Pharmaceutical and Biomedical Analysis,2007,43:1721-1727 ...
App Note for Enhanced Detection and Separation of Anabolic Steroids for Anti-Doping Control Screening by Comprehensive TwoDimensional Gas Chromatography Time-of-Flight Mass Spectrometry (GCxGC-TOFMS)
This article aims to investigate the use and benefits of using comprehensive two-dimensional gas chromatography (GC x GC) and structure-activity relationship modeling for screening and prioritization of organic contaminants in complex matrices. The benefit of applying comprehensive screening techniques to samples with high organic contaminant content is primarily that compounds with diverse physicochemical properties can be analyzed simultaneously. Here, a heavily contaminated industrial area was surveyed for organic pollutants by analyzing soil, sediment, and surface water samples. The hazard of the pollutants were ranked using SARs. The water samples were liquid-liquid extracted using dichloromethane and directly analyzed by GC x GC-time-of-flight mass spectrometry (GC x GC-TofMS). Soil and sediment samples were extracted with dichloromethane in an ultrasonic bath and subjected to gel permeation chromatography to eliminate lipids and humic matter. The low molecular weight fraction was then ...
The investigation of naturally volatile and derivatized metabolites in biological tissues by comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry...
TY - JOUR. T1 - Gas chromatographic mass spectrometric detection of dihydroxy fatty acids preserved in the bound phase of organic residues of archaeological pottery vessels. AU - Hansel, Fabricio A.. AU - Bull, Ian D.. AU - Evershed, Richard P.. PY - 2011/7/15. Y1 - 2011/7/15. N2 - A methodology is presented for the determination of dihydroxy fatty acids preserved in the bound phase of organic residues preserved in archaeological potsherds. The method comprises saponification, esterification, silica gel column chromatographic fractionation, and analysis by gas chromatography/mass spectrometry. The electron ionisation mass spectra of the trimethylsilyl ether methyl ester derivatives are characterised by fragment ions arising from cleavage of the bond between the two vicinal trimethylsiloxy groups. Other significant fragment ions are [M-15](+.), [M-31](+.), m/z 147 and ions characteristic of vicinal disubstituted (trimethylsiloxy) TMSO- groups (Delta(7,8), Delta(9,10), Delta(11,12) and ...
This study examined whether 4-ABP-Hb adducts in RBC (as biomarkers of environmental tobacco smoke exposure) collected several years before the onset of a number of tobacco-related cancers and respiratory diseases may be predictive of disease risk among never smokers or former smokers.. Because of the limited amount of Hb available for the analysis of 4-ABP adducts, the analytic method was improved to obtain samples free of compounds interfering with the analysis. A mixed cation exchange/reverse-phase extraction cartridges for isolation of the analyte and high-resolution gas chromatography-negative ion chemical ionization-mass spectrometry with selective ion monitoring for quantitation was used for analysis and proved suitable for 4-ABP-Hb adduct measurement. Overall, the adduct levels were in good agreement with previous studies, which used larger amounts of Hb (8, 10, 20).. Elevated adduct levels are likely to reflect higher exposure to environmental tobacco smoke, as indicated by the moderate ...
Next, a model was developed that permitted a systematic investigation of peak shape in fluidic modulation. In the case of a non-focusing modulator for comprehensive two-dimensional gas chromatography, the systematic distortions induced when the modulator loads the second-dimension column give rise to a characteristic peak shape. Depending on the operating conditions this systematic distortion can be the dominant component of the second-dimension elution profiles. Understanding the factors that cause different peak shape observations provides a rugged approach to method development. It is shown that low flow ratio can lead to significant peak skewing and increasing the flow ratio reduces the magnitude of peak skewing. Validation of the peak shape model is made by comparison with experimental data ...
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Directory of patents related to Isotope-ratio-monitoring Gas Chromatography-mass Spectrometry Apparatus And Method (3 patents): Isotope-ratio-monitoring gas chromatography-mass spectrometry apparatus and method.; Isotope-ratio-monitoring gas chromatography-mass spectrometry apparatus and method; Isotope-ratio-monitoring gas chromatography-mass spectrometry apparatus and method
High-molecular weight compounds previously were found to be important secondary products from autoxidation of polyunsaturated fatty esters. The contribution of dimers to oxidative deterioration was investigated by analyzing their volatile thermal decomposition products by capillary gas chromatography-mass spectrometry. Dimers were isolated by gel permeation chromatography from autoxidized linolenate and from the corresponding monohydroperoxides, cyclic peroxides and dihydroperoxides. Major volatile decomposition products identified from these oxidative dimers were similar to those formed from the corresponding monomeric hydroperoxides. However, dimers from linolenate hydroperoxides produced more propanal and methyl 9-oxononanoate than the corresponding monomers but less methyl octanoate and much less or no 2,4-heptadienal and 2,4,7-decatrienal. Significant differences in minor volatile products also were observed between dimeric and monomeric products of methyl linolenate oxidation compounds. ...
Time of flight mass spectrometry identifies the elements of a compound by subjecting a sample of ions to a strong electrical field. Illuminating emerging analytical techniques in high-resolution mass spectrometry, Liquid Chromatography Time-of-Flight Mass Spectrometry shows readers how to analyze unknown and emerging contaminants-such as antibiotics, steroids, analgesics-using advanced mass spectrometry techniques. The text combines theoretical discussion with concrete examples, making it suitable for analytical chemists, environmental chemists, organic chemists, medicinal chemists, university research chemists, and graduate and post-doctorate students.. ...
Developing atherosclerotic lesions in hypercholesterolemic rabbits are depleted in zinc, while iron accumulates. This study examined the influence of zinc supplementation on the development of atherosclerosis and used isotope dilution gas chromatography-mass spectrometry techniques to measure biomarkers of oxidative lipid damage in atherosclerotic rabbit aorta. Our previous method for F2-isoprostane measurement was adapted to include the quantitation of cholesterol oxidation products in the same sample. Two groups of New Zealand white rabbits were fed a high cholesterol (1% w/w) diet and one group was also supplemented with zinc (1 g/kg) for 8 weeks. Controls were fed a normal diet. Zinc supplementation did not significantly alter the increase in total plasma cholesterol levels observed in animals fed high cholesterol. However, in cholesterol-fed animals zinc supplementation significantly reduced the accumulation of total cholesterol levels in aorta which was accompanied by a significant reduction in
TY - JOUR. T1 - Determination of bromide in whole blood and urine from humans using gas chromatography-mass spectrometry. AU - Kage, Shigetoshi. AU - Kudo, Keiko. AU - Ikeda, Hideaki. AU - Tsujita, Akira. AU - Ikeda, Noriaki. PY - 2005/3/25. Y1 - 2005/3/25. N2 - We devised a sensitive and simple method for determination of bromide in whole blood and urine from humans using gas chromatography-mass spectrometry. Bromide was alkylated with pentafluorobenzyl p-toluenesulphonate in the mixture of acetone and phosphate buffer (pH 6.8). The derivative obtained was analyzed using gas chromatography-mass spectrometry with the positive-ion EI mode. The lower limit of detection for the compound was 1 mg/l. The calibration curve for bromide was linear over the concentration range from 2 to 100 mg/l. With use of this method, levels of bromide in whole blood and urine were determined in cases of poisoning by inhaled brominated hydrocarbons.. AB - We devised a sensitive and simple method for determination of ...
Volatile organic compounds were quantified during two aircraft-based field campaigns using highly automated, whole air samplers with expedited post-flight analysis via a new custom-built, field-deployable gas chromatography-mass spectrometry instrument. During flight, air samples were pressurized with a stainless steel bellows compressor into electropolished stainless steel canisters. The air samples were analyzed using a novel gas chromatograph system designed specifically for field use which eliminates the need for liquid nitrogen. Instead, a Stirling cooler is used for cryogenic sample pre-concentration at temperatures as low as 165 degrees C. The analysis system was fully automated on a 20 min cycle to allow for unattended processing of an entire flight of 72 sample canisters within 30 h, thereby reducing typical sample residence times in the canisters to less than 3 days. The new analytical system is capable of quantifying a wide suite of C2 to C10 organic compounds at part-per-trillion ...
Since its first bench-top gas chromatograph/mass spectrometer (GC/MS) was sold in 1979, Shimadzu has been a leader in design innovations, such as our front access ion source, high efficiency ion optics, 20,000 u/second scan speed, and post-quadrupole focusing lenses.. Together, these innovations provide unparalleled instrument performance and simplified operation and maintenance. With the addition of the GCMS-TQ8040 triple quadrupole GC-MS/MS, Shimadzu offers a comprehensive series of GC/MS and GC-MS/MS instruments for every application.. Based on the UFMS (Ultra-Fast Mass Spectrometry) features and flexibility of the systems, a full range of solutions for multidimensional analysis, including Comprehensive GC (GCxGC) as well as MDGC is possible as well.. ...
The efficacy of a newly developed gas chromatography-negative ion chemical ionization-mass spectrometry-selected ion monitoring (GC-NICI-MS-SIM) assay for measuring globin adducts of benzo[a]pyrene (B[a]P) and chrysene diol epoxides in human was evaluated. In this pilot study, smokers and nonsmokers were selected as exposed and nonexposed groups. Using [2H12]r-7,t-8,9,c-10-tetrahydroxy-7,8,9,10-tetrahydrobenzo[a]pyren e ([2H12]trans,anti-B[a]P-tetraol) as an internal standard, B[a]P-tetraols released from globin after hydrolysis and derivatization were quantified by GC-NICI-MS-SIM. Levels of trans-1,2-dihydroxy-3,4-epoxy-1,2,3,4-tetrahydrochrysene (chrysene-DE)-globin adducts were estimated by assuming that the recovery and the MS response of the perdeuterated B[a]P-tetraol internal standard reflected the recovery and MS response of chrysene tetraols. The assay was found to be reproducible and sensitive enough to detect both analytes in all samples. The mean levels of B[a]P-tetraols released ...
The current methodology used in quality control of Ecuadorian beverages such as Pájaro azúl, Puro and Pata de vaca is carried out by using conventional gas chromatography; however, it does not allow the fingerprinting of these Ecuadorian spirit beverages and their possible cases of adulteration. In order to overcome this drawback, comprehensive two-dimensional gas chromatography-mass spectrometry (GC × GC-MS) was combined with multivariate data analysis, revealing that compounds like citronellal, citronellol, geraniol, methyl anthranilate, (−)-trans-α-bergamotene, (−)-cis-α-bergamotene and d-limonene can be considered key elements for pattern recognition of these traditional beverages and product adulteration cases. Thus, the two-dimensional chromatographic fingerprints obtained by GC × GC-MS coupled with chemometric analysis, using Principal Component Analysis and Fisher-ratio can be considered as a potential strategy for adulteration recognition, and it may used as a quality assurance system
Savareear, Benjamin, Jacobs, Matthew R and Shellie, Robert A 2014, Multiplexed dual first-dimension comprehensive two-dimensional gas chromatography-mass spectrometry with contra-directional thermal modulation, Journal of Chromatography A, vol. 1365, pp. 183-190, doi: 10.1016/j.chroma.2014.09.014. ...
A survey is made of investigations into the adsorption of polar and labile substances on surfaces within gas chromatographic equipment and of the methods which have been developed to minimize it. A description is given of a gas chromatograph-mass spectrometer in which such methods have been applied for the analysis of trace quantities of sulphur compounds.
was isolated from this hydrocarbon-contaminated wastewater and examined for its ability to utilize hexadecane. This strain was capable to grow on n-hexadecane as the sole source of carbon and energy. The ability of the isolate to degrade nhexadecane was assessed by growth assays and gas chromatography/mass spectrometry analysis. Using GC analysis, it was shown that the strain KSS1060 was able to degrade 62 % of n-hexadecane within 6 days, which mostly (51.6 %) occurred within the first 24 h. Identification of this hexadecane-degrader bacterium was carried out using 16S rDNA sequence analysis. Additionally, characterization of chemical composition of wastewater samples by the use of gas chromatography/mass spectrometry analysis indicated the presence of Hexanal, Benzene methanol, Indanol, 1,2-benzenedicarboxylic acid diethyl ester, diisobutyl phthalate, and Phenol,4,4-(1- methylethylidene) in the major constituents of wastewater. In conclusion, this study can focus on more costefficient ...
In chromatography-based metabonomic research, retention time (RT) alignment of chromatographic peaks poses a challenge for the accurate profiling of biomarkers. Although a number of RT alignment software has been reported, the performance of these software packages have not been comprehensively evaluated. This study aimed to evaluate the RT alignment accuracy of publicly available and commercial RT alignment software. Two gas chromatography/mass spectrometry (GC/MS) datasets acquired from a mixture of standard metabolites and human bladder cancer urine samples, were used to assess three publicly available software packages, MetAlign, MZmine and TagFinder, and two commercial applications comprising the Calibration feature and Statistical Compare of ChromaTOF software. The overall RT alignment accuracies in aligning standard compounds mixture were 93, 92, 74, 73 and 42% for Calibration feature, MZmine, MetAlign, Statistical Compare and TagFinder, respectively. Additionally, unique trends were ...
We compared the value of plasma samples with that of 24-hour urine samples in identifying patients with pheochromocytoma among those with hypertension. We employed specific gas chromatographic-mass spectrometric analysis of both urine and plasma for simultaneous assay of norepinephrine and its neuronal metabolite 3,4-dihydroxyphenylglycol (DHPG). The study population consisted of 1086 patients with hypertension, among them 25 patients with proved pheochromocytoma. Reference ranges for free norepinephrine and DHPG in plasma and urine were established. Measurement of free norepinephrine in 24-hour urine samples provided the best index of a pheochromocytoma. This technique had 100 percent sensitivity and 98 percent specificity among 1192 urine samples, as compared with 82 percent sensitivity and 95 percent specificity among 358 plasma samples. Simultaneous measurement of norepinephrine and DHPG in urine further improved specificity (to 99 percent), but the use of the ratio of norepinephrine to DHPG reduced
Quality Environmental Test Chambers manufacturers & exporter - buy Hplc Gas Chromatograph Mass Spectrometry Analyzer Machine GLPC / GC from China manufacturer.
In this paper, automated sample preparation, retention time locked gas chromatography-mass spectrometry (GC-MS) and data analysis methods for the metabolomics study were evaluated. A miniaturized and automated derivatisation method using sequential oximation and silylation was applied to a polar extract of 4 types (2 types×2 ages) of Arabidopsis thaliana, a popular model organism often used in plant sciences and genetics. Automation of the derivatisation process offers excellent repeatability, and the time between sample preparation and analysis was short and constant, reducing artifact formation. Retention time locked (RTL) gas chromatography-mass spectrometry was used, resulting in reproducible retention times and GC-MS profiles. Two approaches were used for data analysis. XCMS followed by principal component analysis (approach 1) and AMDIS deconvolution combined with a commercially available program (Mass Profiler Professional) followed by principal component analysis (approach 2) were compared.
UMESC Publications. Development and validation of a gas chromatography/mass spectrometry procedure for confirmation of para-toluenesulfonamide in edible fish fillet tissue Idowu, O. R., Kijak, P. J., Meinertz, J. R., and Schmidt, L. J., 2004, Development and validation of a gas chromatography/mass spectrometry procedure for confirmation of para-toluenesulfonamide in edible fish fillet tissue: Journal of Association of Official Analytical Chemists International, v. 87, no. 5, p. 1098-1108.. Abstract. Chloramine-T is a disinfectant being developed as a treatment for bacterial gill disease in cultured fish. As part of the drug approval process, a method is required for the confirmation of chloramine-T residues in edible fish tissue. The marker residue that will be used to determine the depletion of chloramine-T residues from the edible tissue of treated fish is para-toluenesulfonamide (p-TSA), a metabolite of chloramine-T. The development and validation of a procedure for the confirmation of p-TSA ...
Public tender in Salisbury. Supply of two Agilent 7890B Series gas chromatography mass spectrometry flame photometric detection systems. Supply of two Agilent 7890B Series gas chromatography mass spectrometry flame photometric detection systems. voluntary ex ante transparency notice
You searched for: Journal Journal of chromatography Remove constraint Journal: Journal of chromatography Subject gas chromatography-mass spectrometry Remove constraint Subject: gas chromatography-mass spectrometry Subject temperature Remove constraint Subject: temperature ...
Part I - Fluorinated Compounds A method has been developed for the extraction, concentration, and determination of two unique fluorinated compounds from the sediments of Lake Ontario. These compounds originated from a common industrial landfill, and have been carried to Lake Ontario by the Niagara River. Sediment samples from the Mississauga basin of Lake Ontario have been evaluated for these compounds and a depositional trend was established. The sediments were extracted by accelerated solvent extraction (ASE) and then underwent clean-up, fractionation, solvent exchange, and were concentrated by reduction under nitrogen gas. The concentrated extracts were analyzed by gas chromatography - electron capture negative ionization - mass spectrometry. The depositional profile determined here is reflective of the operation of the landfill and shows that these compounds are still found at concentrations well above background levels. These increased levels have been attributed to physical disturbances of ...
Comprehensive two-dimensional (2D) separations are highly beneficial in the characterization of complex samples. The research presented in this dissertation involves the analysis of the small polar molecules comprising the yeast metabolome using commercially available GCxGC-TOFMS instrumentation. The studies described herein are some of the first on metabolomic data using GCxGC-TOFMS and the analysis required a tremendous amount of procedural and software method development. A proof of principle experiment was performed using fermenting and respiring yeast cells. Initially, principal component analysis (PCA) was performed on three selective mass channels (m/z ) to identify the metabolite locations exhibiting changes between sample types. Twenty-six metabolite peaks were reported. Following proof that the GCxGCTOFMS is applicable to the study of yeast metabolite data, an extensive study was performed to determine the ability of GCxGC-TOFMS to detect metabolites and ultimately be utilized to ...
The enhanced resolution of comprehensive two-dimensional gas chromatography (GCxGC) was combined with the increased resolving power, speed, and mass accuracy of the Pegasus® HRTs mass analyzer to confidently characterize molecules in light cycle oil (LCO) and vacuum gas oil (VGO). Optimized chromatographic and mass spectrometry parameters were implemented to improve data acquisition, processing, and heteroatomic speciation of these light to midlevel petroleum fractions. Software tools were utilized to process the data and facilitate robust compound identifications. GCxGC-HRT data was processed using comprehensive Peak Find and resulted in comprehensive characterization of molecules in LCO and VGO samples. Compound classes consisted of, but were not limited to alkanes, cycloalkanes, aromatics, benzothiophenes, and carbazoles. Selective processing of alkylbenzothiophenes and dibenzothiophenes was conducted by retrospectively processing data using rapid two-dimensional, accurate mass Target Analyte
The conviction rate in drug facilitated sexual assault (DFSA) cases is known to be very low. In addition, the potential impact of toxicological results on the case is often not well understood by the judicial authorities. The aims of this study were (1) to obtain more knowledge concerning the prevalence of incapacitating substances in DFSA cases, (2) to create a more efficient DFSA analysis strategy taking background information into account, and (3) to evaluate the potential impact of systematic toxicological analysis (STA) on the final judicial outcome. This small-scale epidemiological study (n = 79) demonstrates that commonly-used illicit drugs, psychoactive medicines and ethanol are more prevalent in DFSA cases in contrast to the highly mediatized date rape drugs. Additionally, via case examples, the interest of performing STA-to prove incapacitation of the victim-in judicial procedures with mutual-consent discussions has been demonstrated as it led to increased convictions. However, more
Slater, C., Hardieck, M., Preston, T. and Weaver, L.T. (1998) Analysis of tert.-butyldimethylsilyl [1-13C]palmitic acid in stool samples by gas chromatography-mass spectrometry with electron impact ionisation: comparison with combustion isotope-ratio mass spectrometry. Journal of Chromatography B: Biomedical Sciences and Applications, 716(1-2), pp. 1-6. (doi:10.1016/S0378-4347(98)00280-1) ...
This study was conducted at the Horticulture Department of Cukurova University, Adana, Turkey, in 2010 to determine the volatile aroma compounds of Morchella mushroom. Fresh samples of Morchella esculenta (Sample 1) and Morchella elata (Sample 2) were collected from Canakkale (Sample 1) and Mersin (Sample 2) provinces in Turkey in the spring of 2010. Volatile aroma compounds were analyzed by headspace gas chromatography mass spectrometry (HS-GC/MS). A total of 31 aroma compounds were identified in the 2 analyzed samples: 7 alcohols, 7 esters, 7 ketones, 3 acids, 2 aldehydes, 1 terpene, phenol, 1-propanamine, geranyl linalool, and quinoline. Seventeen aroma components were identified in Sample 1, and 18 compounds were found in Sample 2. Phenol was determined as the major aroma compound in both Sample 1 and Sample 2, at 50.888% and 58.293% content, respectively. Alcohols, especially 1-octen-3-ol, were detected as the second major aroma components in Sample 1 and Sample 2, at 15.500% and 5.660% ...
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TY - JOUR. T1 - Profile of volatile metabolites in urine by gas chromatography-mass spectrometry. AU - Zlatkis, Albert. AU - Bertsch, Wolfgang. AU - Lichtenstein, H. A.. AU - Tishbee, Arye. AU - Shunbo, Farid. AU - Liebich, M.. AU - Coscia, A. M.. AU - Fleischer, N.. PY - 1973. Y1 - 1973. N2 - Profiles of volatile metabolites of 150 urine samples from normal individuals and 40 samples from subjects with diabetes mellitus have been studied by gas chromatography and mass spectrometry. The technique involves adsorption of the urinary headspace volatiles on Tenax GC, heat desorption with helium, trapping on a cooled precolumn, and chromatography on 100-m × 0.50-mm i.d. nickel columns. Individual profiles were observed over a period of 2 months. Characteristic constituents in normal urines are 2-butanone, 2-pentanone, 4-heptanone, dimethyl disulfide, several alkyl furans, pyrrole, and carvone. In subjects with diabetes mellitus under insulin treatment, high concentrations of pyrazines, ...
This standard is developed for the purposes of enforcing the Law of the Peoples Republic of China on Environmental Protection, protecting the environment, safeguarding the public health, and setting standards for PCBs in soil and sediment. This standard specifies the gas chromatography-mass spectrometry method for the determination of PCBs in soil and sediment. It is the original version.. ...
This standard is developed for the purposes of enforcing the Law of the Peoples Republic of China on Environmental Protection, protecting the environment, safeguarding the public health, and setting standards for the determination of volatile halohydrocarbons in soil and sediment. This standard specifies the purge and trap/gas chromatography-mass spectrometry method for the determination of 35 volatile halohydrocarbons including methyl chloride in soil and sediment.. ...
For the first time, 89 chemical constituents were identified by gas chromatography-mass spectrometry analysis of ethanol extract of Clathria baltica. The chemical examination of et..
5 matching references were found. Baillie, L.A.; Skinner, J.L., , 1988. [all data] Baillie, T.A.; Brooks, C.J.W.; Middleditch, B.S., Comparison of Corticosteroid Derivatives by Gas-Chromatography-Mass Spectrometry, Anal. Chem., 1972, 44, 1, 30-37, https://doi.org/10.1021/ac60309a016 . [all data] Clare, R.A.; Davies, D.S.; Baillie, T.A., The analysis of terbutaline in biological fluids by gas chromatography electron impact mass spectrometry, Biomed. Mass Spectrom., 1979, 6, 1, 31-37, https://doi.org/10.1002/bms.1200060108 . [all data] Rettenmeier, A.W.; Howald, W.N.; Levy, R.H.; Witek, D.J.; Gordon, W.P.; Porubek, D.J.; Baillie, T.A., Quantitative metabolic profiling of valproic acid in humans using automated gas chromatographic/mass spectrometric techniques, Biomed. Environ. Mass Spectrom., 1989, 18, 3, 192-199, https://doi.org/10.1002/bms.1200180308 . [all data] Brash, A.R.; Baillie, T.A., A Comparison of t -Butyldimethylsilyl and Trimethylsilyl Ether Derivatives for the Characterization of ...
TY - JOUR. T1 - Advances in the application of comprehensive two-dimensional gas chromatography in metabolomics. AU - Higgins Keppler, Emily A.. AU - Jenkins, Carrie L.. AU - Davis, Trenton J.. AU - Bean, Heather. N1 - Funding Information: The growth of the field of metabolomics is reflected by the recent investments by the National Institutes of Health (NIH) into the Common Fund Metabolomics program, which supports technology development, infrastructure, training, and an international repository for metabolomics data, the Metabolomics Workbench ( metabolomicsworkbench.org ) [59] . The goal is to generate publicly accessible metabolomics data, following the models of data sharing for genomics and transcriptomics via the GenBank and Gene Expression Omnibus (GEO) databases, respectively. Currently, depositing metabolomics data into public repositories is only encouraged under the NIH Data Sharing policies; however, it is possible that in the near future journal publishers may require data sharing ...
Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a strain of the bacterium Staphylococcus aureus characterized by its multi-drug resistance to penicillins, clindamycin, tetracyclines, macrolides, aminoglycosides, fluoroquinolones, etc. Chromolaena odorata R.M. King & H. Rob is a potential and promising plant that should be exploited for the management of diseases caused by MRSA because its fractions have anti-MRSA activities. The aim of this work was to screen and identify the chemical constituents of the anti-MRSA fractions of C. odorata leaves. Materials and Methods: Seven isolates of MRSA and methicillin-susceptible S. aureus(MSSA) and a control strain S. aureus NCIBB 8588 were used for this study. Fresh leaves of C. odorata were collected from Igbinedion University, Okada environs, Edo State, Nigeria. The fractions obtained were analyzed with a Gas Chromatography-Mass Spectrometry (GC-MS) analyzer to identify their chemical constituents. Results: A total of eight fractions ...
Liquid Chromatography Time-of-Flight Mass Spectrometry (LC-TOFMS) is an analytical platform that is widely used in the study of biological mixtures in the rapidly growing fields of proteomics and metabolomics. The development of statistical methods for the analysis of the very large data-sets that are typically produced in LC-TOFMS experiments is a very active area of research. However, the theoretical basis on which these methods are built is currently rather thin and as a result, inferences regarding the samples analysed are generally drawn in a somewhat qualitative fashion. This thesis concerns the development of a statistical formalism that can be used to describe and analyse the data produced in an LC-TOFMS experiment. This is done through the derivation of a number of probability distributions, each corresponding to a different level of approximation of the distribution of the empirically obtained data. Using such probabilistic models, statistically rigorous methods are developed and ...
The antiprotozoal and antioxidant activities of Viola tricolor and Laurus nobilis have been reported recently. Thus, the existing study pursued to assess the growth inhibition effect of methanolic extract of V. tricolor (MEVT) and acetonic extract of L. nobilis (AELN) against five Babesia parasites and Theileria equi in vitro and in vivo. MEVT and AELN suppressed Babesia bovis, B. bigemina, B. divergens, B. caballi, and T. equi growth at half-maximal inhibitory concentration (IC50) values of 75.7 ± 2.6, 43.3 ± 1.8, 67.6 ± 2.8, 48 ± 3.8, 54 ± 2.1 μg/mL, and 86.6 ± 8.2, 33.3 ± 5.1, 62.2 ± 3.3, 34.5 ± 7.5 and 82.2 ± 9.3 μg/mL, respectively. Qualitative phytochemical estimation revealed that both extracts containing multiple bioactive constituents and significant amounts of flavonoids and phenols. The toxicity assay revealed that MEVT and AELN affected the mouse embryonic fibroblast (NIH/3 T3) and Madin-Darby bovine kidney (MDBK) cell viability with half-maximum effective concentrations (EC50)
TY - JOUR. T1 - Simultaneous determination of phencyclidine and monohydroxylated metabolites in urine of man by gas chromatography-mass fragmentography with methane chemical ionization. AU - Cone, Edward J.. AU - Buchwald, William. AU - Yousefnejad, David. PY - 1981/5/8. Y1 - 1981/5/8. N2 - Phencyclidine and monohydroxy metabolites were measured in human urine using gas chromatography-mass fragmentography with methane chemical ionization. Samples were extracted either untreated or following acid hydrolysis, derivatized with heptafluorobutyric anhydride, separated on a 3% SE-30 column and analyzed by mass fragmentography. The assay was sensitive to ca. 0.01 μg/ml for phencyclidine and ca. 0.05 μg/ml for the metabolites. Urine samples from five human subjects enrolled in a methadone maintenance program who had ingested phencyclidine were analyzed. The phencyclidine concentration ranged from 0.3 to 23.7 μg/ml. The concentrations of metabolites ranged from 0 to 1.8 μg/ml. A new monohydroxy ...
TY - JOUR. T1 - Gas chromatographic-mass spectrometric fragmentation study of flavonoids as their trimethylsilyl derivatives. T2 - Analysis of flavonoids, sugars, carboxylic and amino acids in model systems and in citrus fruits. AU - Füzfai, Zs. AU - Molnár-Perl, I.. PY - 2007/5/11. Y1 - 2007/5/11. N2 - The fragmentation patterns and quantitation possibilities of three anthocyanidins (pelargonidin, cyanidin, malvidin), one flavonol (quercetin), two flavones (apigenin, luteolin) and two flavanones (naringenin, hesperetin) have been investigated as trimethylsilyl and as trimethylsilyl (oxime) derivatives by gas chromatography-mass spectrometry. Results proved that anthocyanidins and flavanones form trimethylsilyl (oximes), while flavonol and flavones provide simple trimethylsilyl derivatives. In all cases, characteristic fragments of high masses are formed proper for quantitation purposes. Hydrolysis conditions for naringin, hesperidin and rutin have been optimized, resulting in the quantitative ...
TY - JOUR. T1 - Improved separation of the 209 polychlorinated biphenyl congeners using comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry. AU - Focant, Jean François. AU - Sjödin, Andreas. AU - Patterson, Donald G.. N1 - Funding Information: J.-F. Focant is financially supported by the Oak Ridge Institute for Science and Education (ORISE), a Department of Energy (DOE) facility managed by Oak Ridge Associated Universities (ORAU). PY - 2004/6/25. Y1 - 2004/6/25. N2 - The separation of the 209 polychlorinated biphenyl (PCB) congeners has been studied using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC-TOFMS). Four column combinations based on thermally stable phases, DB-1/HT-8, DB-XLB/HT-8, DB-XLB/BPX-50, and HT-8/BPX-50, have been investigated. The HT-8/BPX-50 set produced the best separation. The distribution of the 100 to 150 ms wide peaks was highly structured in the chromatographic space and based on the ...
Pellizzari, E., Bunch, J. E., Bursey, J. T., Berkley, R. E., Sawicki, E., & Krost, K. (1976). Estimation of N-Nitrosodimethylamine Levels in Ambient Air by Capillary Gas-Liquid Chromatography/Mass Spectrometry. Analytical Letters, 9, 579 ...
Comparison of extraction methods for quantitation of methionine and selenomethionine in yeast by species specific isotope dilution gas chromatography-mass spectrometry
Phytosterols are potential endocrine-disrupting compounds. Quantification of phytosterols was carried out in sediments from four coastal zones and two rivers in south-central Chile. Sterol concentrations were determined by capillary gas chromatography-mass spectrometry and the sources of sedimentary organic matter were determined using sterol ratios and lipid biomarkers. Total sterol concentrations (0.03 to 10.4 μg g-1) were within the range reported for other marine ecosystems and the β-sitosterol concentration (0.01 to 2.01 μg g-1) was lower than previously reported for the upwelling system off Peru. Some coastal stations adjacent to the rivers had β-sitosterol of terrestrial origin. High concentrations of β-sitosterol were also found in sediments from more oceanic stations, supporting the notion that this sterol can also be produced by phytoplankton. No differences in the sterol concentration between the coastal zones were found. However, significant differences were found between almost ...
article{191ea318-159e-43da-9392-05ee7bf33a0d, author = {Wady, Loay and Bunte, Annicka and Pehrson, Christina and Larsson, Lennart}, issn = {1872-8359}, language = {eng}, number = {3}, pages = {325--332}, publisher = {Elsevier}, series = {Journal of Microbiological Methods}, title = {Use of gas chromatography-mass spectrometry/solid phase microextraction for the identification of MVOCs from moldy building materials.}, url = {http://dx.doi.org/10.1016/S0167-7012(02)00190-2}, volume = {52}, year = {2003 ...
TY - JOUR. T1 - Screening for anabolic steroids and related compounds in illegal cocktails by liquid chromatography/time-of-flight mass spectrometry and liquid chromatography/quadrupole time-of-flight tandem mass spectrometry with accurate mass measurement. AU - Nielen, M.W.F.. AU - Vissers, J.P.C.. AU - Fuchs, R.E.M.. AU - van Velde, J.W.. AU - Lommen, A.. PY - 2001. Y1 - 2001. N2 - Findings of illegal hormone preparations such as syringes, bottles, cocktails, and so on, are an important information source for the nature of the current abuse of anabolic steroids and related compounds as growth-promoting agents in cattle. A new screening method for steroids in cocktails is presented based on liquid chromatography (LC) with diode-array UV-absorbance detection and electrospray ionization time-of-flight mass spectrometry (ESI-TOFMS). Accurate mass measurements were performed at a mass resolution of 4000 using continuous introduction of a lock mass through a second (electro)sprayer. Similar ...
Large and ever-increasing numbers of chemicals, including large quantities of a broad spectrum of organic compounds are used in modern society. More than 30 000 of the more than 100 000 chemical substances registered in the EU are estimated to be daily used, of which many will be discharged into the waste-streams handled by municipal sewage treatment plants (STPs). The main objective of the work underlying this thesis was to improve understanding of the relationships between the characteristics of sewage contaminants and their sewage treatment efficiency. Further objectives were to examine the relationships between socio-economic uses of chemicals and sludge quality, and the effects of regulatory actions on sludge quality.. The quality of the sewage sludge and the levels and distribution patterns of the sludge contaminants, both within and between the STPs, seem to remain quite constant over time. The overall findings indicate that the levels of contaminants in sewage sludge seem to be largely ...
Methods Patients with sterile brain injury requiring intubation and ventilation on the intensive care unit were eligible for inclusion. Serial clinical and breath data were obtained three times a week, from admission up to a maximum of 10 days. Bronchial lavage for semiquantitative culture was collected immediately prior to breath sampling. Breath samples were collected in triplicate for off-line analysis by thermal-desorption/gas chromatography/time-of-flight mass spectrometry. Breath data were recorded as retention time/mass ion pairs, and analysed (pathogen present vs absent) by ANOVA-mean centre principal component analysis.. ...
AIMS: This study compared serum metabolites of demented patients (Alzheimers disease and vascular dementia) and controls, and explored serum metabolite profiles of nondemented individuals 5 years preceding the diagnosis.. METHODS: Cognitively healthy participants were followed up for 5-20 years. Cognitive assessment, serum sampling, and diagnosis were completed every 5 years. Multivariate analyses were conducted on the metabolite profiles generated by gas chromatography/time-of-flight mass spectrometry.. RESULTS: A significant group separation was found between demented patients and controls, and between incident cases and controls. Metabolites that contributed in both analyses were 3,4-dihydroxybutanoic acid, docosapentaenoic acid, and uric acid.. CONCLUSIONS: Serum metabolite profiles are altered in demented patients, and detectable up to 5 years preceding the diagnosis. Blood sampling can make an important contribution to the early prediction of conversion to dementia.. ...
TY - CHAP. T1 - Polar Lipid Profiling by Supercritical Fluid Chromatography/Mass Spectrometry Method. AU - Yamada, Takayuki. AU - Nagasawa, Yumiko. AU - Taguchi, Kaori. AU - Fukusaki, Eiichiro. AU - Bamba, Takeshi. PY - 2015/4/15. Y1 - 2015/4/15. N2 - Polar lipids, such as phospholipids (PLs) and sphingolipids, are abundant in plant oils and are the major component of biological membranes. These lipids also play important physiological roles in cellular signaling. High-throughput simultaneous analyses for all types of lipids, including polar lipids, are favorable to elucidate the function of individual lipid molecular species or to distinguish among phenotypes. The research field aimed at comprehensive lipid profiling is called lipidomics. Because of the diversity of chemical structures and the wide range of polarities in lipids, a powerful separation technique is required for comprehensive lipid profiling. Supercritical Fluid Chromatography (SFC)/Mass Spectrometry (MS) is the ideal tool for ...
Enantioselective determination of chlordane components using chiral high-resolution gas chromatography-mass spectrometry with application to environmental samples
Persistence Market Research has studied the overall performance of the global liquid chromatography-mass spectroscopy market and have observed that the market is likely to show significant growth owing to a rising demand for liquid chromatography-mass spectroscopy systems across various applications.
Article Improved derivatization protocol for simultaneous determination of alkylphenol ethoxylates and brominated flame retardants followed by gas chromatography-mass spectrometry analyses. An improved derivatization protocol for the simultaneous det...
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Negative chemical ionization mass spectrometry with a mixture of isobutane, methylene chloride, and oxygen as the reagent gas has been used to explore contamination of environmental substrates with xenobiotic chemicals. The substrates in question, fish tissue, human seminal plasma, and human adipose tissue, were cleaned up by one of the following three cleanup procedures: (1) continuous liquid-liquid extraction steam distillation; (2) gel-permeation chromatography; and (3) adsorption on activated carbon followed by elution with toluene. The third procedure was used only for the examination of planar polychlorinated aromatic hydrocarbons in environmental samples. Using these techniques, the authors have found evidence for contamination of fish samples with polychloronaphthalenes, polychlorostyrenes, polychlorobiphenyls, polychlorodibenzofurans, and polychlorodibenzodioxins among other chemicals. The polychlorodibenzodioxins appeared only in the spectra of extracts of fish obtained from the ...
A simple, rapid and sensitive method based on microextraction in packed syringe (MEPS), in combination with gas chromatography-mass spectrometry (GC-MS) was developed. Polyaniline (PANI) nanowires network was synthesized and used as sorbent of MEPS for the multiresidue determination of selected analytes from triazine, organochlrorine and organophosphorous pesticides in aqueous samples. The PANI na ...
Humulene is one of the components of the essential oil from the flowering cone of the hops plant, Humulus lupulus, from which it derives its name. The concentration of humulene varies among different varieties of the plant but can be up to 40% of the essential oil.[3] Humulene and its reaction products in the brewing process of beer gives many beers their hoppy aroma. Noble hop varieties have been found to have higher levels of humulene, while other bitter hop varieties contain low levels.[4][unreliable source?] Multiple epoxides of humulene are produced in the brewing process. In a scientific study involving gas chromatography-mass spectrometry analysis of samples and a trained sensory panel, it was found that the hydrolysis products of humulene epoxide II specifically produces a hoppy aroma in beer.[5][6] α-Humulene has been found in many aromatic plants on all continents, often together with its isomer β-caryophyllene. Proven α-humulene emitters into the atmosphere are pine trees,[7] ...
This study was performed to investigate the effectiveness of garlic and onion compared to butylated hydroxy toluene (BHT) on retarding oxidation of cold infused sunflower oil stored for 6 months. Garlic and onion powders or their essential oils were added to sunflower oil in a wide range of concentrations. Sensory evaluation of the flavored oil samples was carried out. Panelists preferred significantly the sunflower oil flavored by cold infusion with garlic and onion powders at 5% and 10 % levels or their essential oils at 0.01% and 0.02% levels. The progress of oxidation was assessed in terms of acid value, peroxide value, and oxidative stability determined by Rancimat. The yield and Gas Chromatography-Mass Spectrometry analysis of the garlic and onion essential oils were determined. These results suggested that garlic or onion could be used as a natural flavoring material for improving oxidative stability of sunflower oil ...
Deoxynivalenol (DON) is the most frequently detected mycotoxin in cereal and cereal-based products, and a continuous monitoring of this toxin in foodstuffs is highly desirable. In this sense,a QuEChERS based extraction and gas chromatography-tandem mass spectrometry detection is proposed to determine DON in an appetizer largely consumed, the wheat-based snacks. In this study, a total of 40 samples were analyzed. The samples were divided into two groups based on the composition. Extraction was carried out with acetonitrile followed by a dispersive solid phase extraction and analyzed for DON content by gas chromatography-tandem mass spectrometry (GC-QqQ-MS/MS) method. The overall occurrence of samples with DON was 67.5%, with maximum content of 61μg/kg. In spite of its high incidence, DON concentrations found in samples were much lower than the maximum limit established in the current European legislation (500 μg/kg) for the foodstuff evaluated. Data obtained indicated a low exposure to DON ...
Solid phase microextraction (SPME) is a solventless extraction technique that combines sample preparation and sample introduction into a gas chromatograph into a single step. For the past 20 years, solid-phase micro-extraction (SPME) has been used in numerous fields such as: food analysis, including juices, alcohols fruits and vegetables for volatiles, aroma, caffeine, fatty esters, environmental applications including volatile organic contaminants, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, phenols, pesticides, steroids, herbicides, acid/neutral/base compounds, and organometallic compounds from water, air, soil, sludge, and sediment samples and in biomedical analysis. This work demonstrates the extension of the limitations of SPME with respect to extraction and analysis of a) extension of headspace SPME to larger polycyclic aromatic hydrocarbons from fish oil b) less volatility analytes, combination of SPME-Gas Chromatograph -Mass Spectrometer -Mass Spectrometer (SPME-GC-MS-MS) to
Examples of application of pyrolysis-gas chromatography-mass spectrometry technique for identification of different polymeric materials are demonstrated.
Examples of application of pyrolysis-gas chromatography-mass spectrometry technique for identification of different polymeric materials are demonstrated.
Mitochondrial dysfunction plays a role in a wide range of diseases resulting in an enormous public health burden. The goal of this thesis is to identify metabolic pathways that are disrupted in response to mitochondrial insults. A large proportion of this work is based on the generation of stable isotope labelled metabolites to allow for the rigorous quantification of intracellular metabolites by liquid chromatography-mass spectrometry. Once developed, this methodology was employed in cell culture models initially to characterize an unidentified acyl-CoA thioester induced by propionate metabolism. This novel pathway was identified as the direct formation of 2-methyl-2-pentenoyl-CoA, and using isotopic labeling by metabolic precursors served as a critical component to this pathway elucidation. These same techniques were then applied to studying rotenone, a mitochondrial complex I inhibitor associated with Parkinsonâ??s disease. Previous work by our group has shown that rotenone inhibits components of
TY - JOUR. T1 - Determination of active hydrogen in organic compounds by electron‐impact mass spectrometry. AU - Dinya, Z.. AU - Lipták, Miklós. AU - Szabó, Pál. AU - Sztaricskai, F.. AU - Vékey, K.. PY - 1992. Y1 - 1992. N2 - We report here detailed studies of Bose et al.s (J. Org. Chem. 47, 4008 (1982)) simple method for obtaining electron‐impact (EI) mass spectra from non‐volatile and/or thermolabile organic compounds by using ammonium salts. Good quality mass spectra can be obtained by mixing the analyte with different ammonium salts (mainly with NH4Cl) in a given ratio, the mixture being introduced through a conventonal direct probe. A wide variety of ammonium salts has been used to study the effect of the anion and to determine the optimum analyte:NH4X ratio and the other experimental parameters (i.e., electron energy, source temperature etc). A very simple and cheap means of determination of active hydrogen in hydroxyl, carboxyl, sulfhydryl, amino and amido etc groups by EI ...
An analytical method has been established for the quantitative determination of 48 gaseous volatile organic compounds (VOCs) that were detected in the outdoor environment in Western Singapore by Thermal Desorption Gas Chromatography Mass Spectrometry (TD-GCMS). Tenax/Carbopack X multi-sorbent tubes were evaluated for active sampling performance and the method was validated using VOC standard solutions. The procedure exhibited repeatability with relative standard deviation (%RSD) values ≤ 10%, linearity with R2 values ≥ 0.99 for concentrations from 0.02 to 500 ng, VOC standards breakthrough ≤ 5% , tube desorption efficiencies ~100% and the majority of recoveries were between 61% to 120%. 30 mL/min flow rate coupled with sampling volumes of 1 L and 5 L gave the best results for sampling breakthrough and reproducibility during air sampling. Most of the target analytes exhibited acceptable breakthrough ≤ 5%, reproducibility ≤ 20% and method detection limits below 0.5 ppbv. The analyte ...
Background and objectives: Ferula assa-foetida (asafoetida) is a native Iranian species which grows in different regions and climates in Iran. The plant is well known in Iranian Traditional Medicine as well as folk medicine for treatment of diseases. Several studies have been carried out on the essential oil of this species collected from different areas of Iran. This study is the first report about the essential oil of the plant collected from Neishabour mountains that is a potent area for growing this valuable plant species. Methods: Essential oil of the aerial part of Ferula assa-foetidawhich wascollected from Neishabour, Iran, was analyzed by gas chromatography-mass spectroscopy (GC/MS). The minimum inhibitory concentrations of the essential oil was investigated against both Gram-positive (Staphylococcus epidermidis, Staphylococcus aureus, Bacillus subtilis) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia) bacteria using microdilution method. Results: Twenty three
The quality-control lab is equipped with a wide array of instrumentation, including gas chromatograph / mass spectrometers (GC/MS) and a high-field NMRs. Chemistry laboratories are equipped with apparatus for both large-scale (50+ liters) and microscale chemistry, which includes equipment for high-pressure gas reactions, pH and temperature-controlled enzyme chemistry, high-resolution distillation processes, and catalytic reduction with both hydrogen and deuterium . The production laboratories are also equipped with analytical equipment for in-process testing. All of these resources allow us to consistently produce products with high chemical and isotopic purity. All our production is evaluated before and after packaging.. Our experience and skill allow us to obtain a chemical purity of NMR deuterated solvents higher or equal to 99,9 ...
Determination of 1,8 Cineole in Fresh Rosemary and Sage Leaves by Solid-phase Microextraction and Gas Chromatography/Mass Spectrometry
TY - JOUR. T1 - Branched chain amino acids as a major source of alanine nitrogen in man. AU - Haymond, M. W.. AU - Miles, J. M.. PY - 1982. Y1 - 1982. N2 - In vitro perfusion and incubation studies and recent investigations in dogs suggest that branched chain amino acids (BCAA)may be a major source of alanine nitrogen. To determine the contribution of BCAA nitrogen to the formation of alanine in man, seven postabsorptive adults received prime-dose constant infusions of 15N-leucine, L-[6,6,6-2H3] leucine, and L-[2,3,3,3-2H4] alanine; isotopic enrichment was determined in arterialized venous plasma samples by gas chromatography-mass spectroscopy. At substrate and isotope steady state, alanine flux and the rate of 15N alanine appearance were 5.4 ± 0.3 μmol/kg.min and 32 ± 2 nmol/kg.min, respectively. Leucine nitrogen flux was significantly greater than that of leucine carbon flux (2.54 ± 0.25 vs. 1.90 ± 0.10 μmol/kg.min, respectively; P , 0.001). Greater flux of leucine nitrogen when compared ...
The distinction between autochthonous, and oil-like origin of organic matter in geological sediments can be performed on the basis of n-alkane abundance and distribution patterns, determined by gas chromatography, or on the basis of the carbon-isotope ratio (delta (CPDB)-P-13) patterns of dominant n-alkanes, determined by gas chromatography-mass spectroscopy. Here we present solutions for automatic classification of organic matter origin in geological sediments, based on artificial neural networks ...
The non-invasive nature of volatile organic compound (VOC) sampling from skin makes this a priority in the development of new screening and diagnostic assays. Evaluation of recent literature highlights the tension between the analytical utility of ambient ionisation approaches for skin profiling and the practicality of undertaking larger campaigns (higher statistical power), or undertaking research in remote locations. This study describes how VOC may be sampled from skin and recovered from a polydimethylsilicone sampling coupon and analysed by thermal desorption (TD) interfaced to secondary electrospray ionisation (SESI) time-of-flight mass spectrometry (MS) for the high throughput screening of volatile fatty acids (VFAs) from human skin. Analysis times were reduced by 79% compared to gas chromatography-mass spectrometry methods (GC-MS) and limits of detection in the range 300 to 900 pg cm−2 for VFA skin concentrations were obtained. Using body odour as a surrogate model for clinical testing ...
Drug use histories were collected from 100 subjects recruited from the dance scene in and around Glasgow. In addition, each subject donated a hair sample that was analyzed by gas chromatography/mass spectrometry (GC/MS) for amphetamine (AP), methamphetamine (MA), 3,4-methylenedioxyamphetamine (MDA), and 3,4-methylenedioxyethylamphetamine (MDEA). The hair samples were analyzed in two 6 cm segments or in full, ranging from 1.5 to 12 cm, depending on the length of the hair. Approximately 10 mg of hair was ground to a fine powder before treatment with B-glucuronidase/aryl sulfatase. A solid-phase extraction procedure was conducted, followed by derivatization with pentafluoropropionic anhydride (PFPA). All extracts were analyzed by GC/MS. Of the 139 segments analyzed, 77 (52.5 percent) were positive for at least one of the five amphetamines. The drug concentrations found in the hair were compared with the self-reported drug histories. A concordance of greater than 50 percent was found between the ...
This review deals with overview of methods of multidimensional gas chromatography (MDGC), the classical meaning- conventional heart-cut MDGC, and the comprehensive two-dimensional gas chromatography (GC×GC). MDGC is widely used because it increases required separation efficiency, which cannot be achieved by one-dimensional gas chromatography. Selected applications in food quality and safety, monitoring of environment, food authentication are summarized. This review summarizes the advances and applications of MDGC that have been published over last 10 years. ...
The composition of detectable small organic compounds in the ethanol extract of Achillea micrantha was defined by means of gas chromatography-mass spectrometric analysis. There we..
PCB signatures can be used for source identification, exposure studies, age dating and bio-monitoring. This study uses comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GCxGC-ToFMS) to produce a PCB signature comprised of over 80 PCBs for individual Leachs storm petrels (Oceanodroma leucorhoa). The Leachs storm petrel is a relatively small, elusive, understudied pelagic bird, which only returns to remote islands under darkness during the breeding season. Samples were obtained from 25 Leachs storm petrels found dead in Canada and the UK following storm events in 2006 and 2009. Tissue samples were extracted and analysed by GCxGC-ToFMS and results showed that 83 PCB congeners were present in ,60% of samples. An assessment of the PCB signature in four different tissue types showed that it did not vary greatly in samples obtained from the gut, heart, liver and stomach. Multivariate statistical analysis identified a distinctive PCB signature in birds from ...
A method for the determination of cocaine (COC), benzoylecgonine (BE), ecgonine methyl ester (EME), and ecgonine (ECG) in plasma by liquid chromatography-mass spectrometry (LC-MS-MS) was developed. The analytes were isolated from human plasma by subsequent solid-phase extraction and were separated on a Zorbax Eclipse XDB-C8 narrow-bore column using an ammonium acetate buffer/acetonitrile/methanol gradient. A Turbolonspray® source was used for ionization. The analytes were characterized by their particular molecular ion and several fragments. Multiple reaction monitoring (MRM) was used for isolation and quantitation. The assay was rapid, highly sensitive, and reliable. The method was applied to monitor the in vitro degradation of cocaine in plasma. Fresh unpreserved and preserved (0.25 % KF) plasma samples were spiked with 1000 ng cocaine/mL. Aliquots of both series were stored at 4°C and 20°C and were analyzed at selected storage times of up to 15 days. In all samples, degradation of cocaine ...
To better understand the coalification process, we have conducted numerous studies of the chemical structural composition of xylem tissue from gymosperm wood and related woods that has been coalified to varying degrees. The studies presented here, examine the chemical nature of buried and coalified xylem tissue at the molecular level. To achieve this, we employed pyrolysis/gas chromatography (py/gc) and pyrolysis/gas chromotography/mass spectrometry (py/gc/ms). Pyrolysis techniques have been used to examine peat, coal, coalified wood, and related substances. However, the technique has not been previously applied to a systematic and histologically-related series of coalified woods. It is particularly useful to compare the results from pyrolytic studies with the data obtained from solid-state **1**3C NMR....
Gas chromatography-mass spectrometry (GC-MS) and liquid chromatographymass spectrometry (LC-MS) are powerful analytical techniques that combine the separation power in a stationary phase with the detection power of mass spectrometry. GCMS and LC-MS have gained dominant positions in identifying and quantifying different analyte species due to their high selectivity, high sensitivity, and high reproducibility. My research utilizes the analytical power of LC-MS and GC-MS to address two environmental issues: 1) Identification of biodegradation products of the ionic liquid 1- butyl-3-methylimidazolium chloride (BMIMCl) by an activated sludge microbial community using LC-MS and 2) identification and quantification of polycyclic aromatic hydrocarbons (PAHs) in the Kalamazoo River oil spill using GC-MS. Three major metabolites from BMIMCl biodegradation were identified, and their structures were confirmed using MS/MS and 1H-NMR techniques. Many PAHs were identified, and their concentrations were quantified in
As a commercial laboratory specializing in organic & inorganic analysis of hazardous waste, waste water, soil, and petroleum product samples, our continued existence depends upon quality of service and timely turnaround. We provide very competitive pricing along with technical services under price schedule and contract arrangements. Analytical methodology employed meets the requirements of the USEPA and the National Environmental Laboratory Accreditation Conference (NELAC). Quality Control   Instrumentation Laboratory instruments play a vital role in reporting timely and accurate results. With the needs of our clients in mind, NAS keeps up-to-date by investing in the latest analytical instrumentation which include, but are not limited to:   Gas Chromatograph-Mass Spectroscopy (GC-MS) Gas Chromatograph (GC) Systems Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) Ion-Chromatography (IC) High Pressure Liquid Chromatography (HPLC)
Applications of the developed procedure based on pyrolysis-gas chromatography (Py-GC) and principal component analysis (PCA) for the characterization of plastic bonded explosives (PBXs) are described. Due to difficulties with the commonly used normalization method a new normalization method was developed and applied in this investigation. The patterns in the score plots obtained after PCA of the Py-GC results appeared much clearer using this new method. PBX samples were examined on homogeneity, influence of the amount of antioxidant (Flexzone) and the crosslink density. It appears that PBXs were inhomogeneous despite a thorough mixing of the constituents during the preparation. Aging experiments were performed on samples which differed in the amount of Flexzone and in the crosslink density. As more Flexzone was added the change in the pattern of the GC-peaks became less. No relation could be found between the stability of PBXs and the crosslink density. Finally, a comparison was made between Dutch
The enzymatic degradation of cocaine in blood samples, even during transport to a forensic laboratory, is a common problem in toxicological analysis. This can be avoided by the use of blood-sampling devices such as gray-top Vacutainers containing the cholinesterase inhibitor sodium fluoride. In the present study, which included 147 authentic cases, blood samples were collected into two different tubes, one containing fluoride/oxalate and one without stabilizing agents. In all cases, both samples were analyzed for drugs of abuse using Abbott FPIA immunoassays after precipitation and gas chromatography-mass spectrometry (GC-MS) for quantitative analysis. The cannabinoid immunoassay showed markedly lower values in the fluoride-containing samples; this was investigated further and could be explained by hemolysis of these samples. In addition, the concentrations of 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid (THCCOOH) were lower in these samples. A stability study with the THCCOOH acyl ...
Separation Systems Inc, sells & supports gas chromatography (GC) & mass spectrometry (GC-MS) instruments for petroleum refineries & petroleum derivatives.
Hair Testing for a 90-Day Drug Use History. Hair Follicle Testing for drugs is the one of the only ways to get an in depth assessment of up to 90 days in the past to determine if someone has been using drugs. This is a great test for an employer or parent.. Simple specimen collection and highly accurate results that meet the same reference standards as urine testing. In addition, there are no known methods for sample adulteration (hair washing will not dilute the sample). Because specimen collection can be directly observed, the risk of adulteration is even further reduced. This is an excellent test for pre-employment drug testing!. We get the results back to you quicker: Negative results are reported within 24 hours of receipt at the laboratory, and positive results are confirmed using gas chromatography/mass spectrometry (GC/MS) or gas chromatography/mass spectrometry/mass spectrometry (GC/MS/MS) within 48 to 72 hours. Hair testing is also forensically defensible.. When compared with urine ...
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... (GC-MS) is an analytical method that combines the features of gas-chromatography and mass ... "Early gas chromatography/mass spectrometry". Journal of the American Society for Mass Spectrometry. 4 (5): 367-371. doi:10.1016 ... Amirav A, Gordin A, Poliak M, Fialkov AB (2008). "Gas chromatography-mass spectrometry with supersonic molecular beams". J Mass ... Gas chromatography-mass spectrometry. *Liquid chromatography-mass spectrometry. *Pyrolysis-gas chromatography-mass spectrometry ...
"Gas Chromatography-Mass Spectrometry". American Chemical Society. Retrieved 19 Nov 2019.. *^ "Marine Surplus Seller, Issues 13- ... Harrington of Bendix Aviation in the 1950s led to the combination of gas chromatography and mass spectrometry, and the ... development of Gas chromatography-mass spectrometry instrumentation. Beginning in the 1960s, Bendix produced scientific ... Criteria was met for hostile and non-hostile environments that provided seals against liquids and gasses. ...
"Early Gas Chromatography/Mass Spectrometry". Journal of the American Society for Mass Spectrometry. 4 (5): 367-371. doi:10.1016 ... These include high-performance liquid chromatography, gas chromatography-mass spectrometry, atomic absorption spectroscopy, ... "Gas Chromatography-Mass Spectrometry". American Chemical Society. Retrieved 19 Nov 2019. Gohlke, Roland S.; McLafferty, Fred W ... the most important advancements in forensic chemistry came in 1955 with the invention of gas chromatography-mass spectrometry ( ...
This led to the development of Gas chromatography-mass spectrometry instruments such as the Bendix MA-2 Time-of-Flight Mass ... "Gas Chromatography-Mass Spectrometry". American Chemical Society. Retrieved 19 Nov 2019. CS1 maint: discouraged parameter (link ... Harrington at Bendix Aviation to demonstrate the potential of combining gas chromatography and mass spectrometer. ... MSA and Cousteau-Gagnon Demand Breathing Appliances for Descents to 400 Feet and the Measurement of the Amounts of Gas Required ...
"Gas Chromatography-Mass Spectrometry". American Chemical Society. Retrieved 19 Nov 2019. National Historic Chemical Landmarks ( ... in Chemistry Steroid Medicines and Upjohn Innovation Gas Chromatography-Mass Spectrometry, Midland, Michigan Mann, Benjamin W ... now owned by the Massachusetts Institute of Technology) in Cambridge, Massachusetts. The discovery and isolation of phytochrome ... "Neil Bartlett and Reactive Noble Gases". National Historic Chemical Landmarks. American Chemical Society. Archived from the ...
"Gas Chromatography-Mass Spectrometry". American Chemical Society. Retrieved 19 Nov 2019. Grayson, Michael A. (2002). Measuring ... Robert Emmet Finnigan (born May 27, 1927) is an American pioneer in the development of gas chromatography-mass spectrometry ... An EPA manual for organic analysis using gas chromatography - mass spectrometry. Environmental Protection Agency. pp. 2, 4. ... The Encyclopedia of Mass Spectrometry Volume 9: Historical Perspectives, Part B: Notable People in Mass Spectrometry. Elsevier ...
"Gas Chromatography-Mass Spectrometry". American Chemical Society. Retrieved 19 November 2019. D.Sc, F. W. Aston M. A. (1 ... KM Downard (2007). "Francis William Aston - the man behind the mass spectrograph". European Journal of Mass Spectrometry. 13 (3 ... The British Mass Spectrometry Society awards the Aston Medal in his honour. "Francis W. Aston - Biographical". NobelPrize.org. ... The exact mass of many isotopes was measured leading to the result that hydrogen has a 1% higher mass than expected by the ...
ISBN 978-1-60774-172-5. Linskens, Hans-Ferdinand; Jackson, John F. (2012-12-06). Gas Chromatography/Mass Spectrometry. Springer ...
"Early gas chromatography/mass spectrometry". Journal of the American Society for Mass Spectrometry. 4 (5): 367-71. doi:10.1016/ ... "Time-of-Flight Mass Spectrometry and Gas-Liquid Partition Chromatography". Analytical Chemistry. 31 (4): 535-541. doi:10.1021/ ...
Using gas chromatography and mass spectrometry. (E,E) 9,12-octadecadienoic acid, methyl ester, 9-Octadecenoic acid(Z)-,methyl ...
... gas chromatography - mass spectrometry; ICP-MS, inductively coupled plasma - mass spectrometry; CO, carbon monoxide, VOC, ... ultra-performance liquid chromatography-mass spectrometry; HPLC-DAD-MMI-MS, high performance liquid chromatography-diode array ... Abbreviations: TSNA, tobacco specific nitrosoamines; LC-MS, liquid chromatography-mass spectrometry; MAO-A and B, ... In physics, a vapor is a substance in the gas phase whereas an aerosol is a suspension of tiny particles of liquid, solid or ...
Gas Chromatography, Infrared Spectrometry or Mass Spectrometry is used in combination with the color test to identify the type ... Check date values in: ,access-date= (help) Lehrer, M. (1998). "The role of gas chromatography/mass spectrometry. Instrumental ... and identifying human remains of victims from mass disasters or missing person cases. It is also used to link suspects or ...
"Gas Chromatography Mass Spectrometry (GC-MS) Information , Thermo Fisher Scientific - US". www.thermofisher.com. Retrieved 2018 ... in 1971 after they demonstrated that gas chromatography-mass spectrometry (GC-MS) could be used to measure compounds present in ... Dettmer, Katja; Aronov, Pavel A.; Hammock, Bruce D. (2007). "Mass spectrometry-based metabolomics". Mass Spectrometry Reviews. ... Dettmer K, Aronov PA, Hammock BD (2007). "Mass spectrometry-based metabolomics". Mass Spectrometry Reviews. 26 (1): 51-78. ...
Gas chromatography-mass spectrometry for atmospheric analysis (MGAK). Developed by Russia. Power source The science and ... The science payload mass is about 45 kg and consists of: The Lander Radioscience experiment (LaRa) will study the internal ...
... using gas chromatography-mass spectrometry and trimethylsilyl derivatives". Industrial Crops and Products. 108: 36-43. doi: ... Because CO2 is gas at normal atmospheric pressure, it leaves no trace of itself in the final product. The equipment for CO2 ... The remaining waxy mass is known as a concrete. The concrete is then mixed with alcohol which dissolves the aromatic ... Under normal pressure CO2 changes directly from a solid to a gas in a process known as sublimation.) The supercritical fluid ...
These included mass spectrometry and gas chromatography instruments. They have since divested these products to Scion ... laboratory gas chromatography (GC), and GC-triple quadrupole mass spectrometer (originally designed by Bear Instruments and ... Later, the company would expand their product range with MRI, FTIR and FT-Raman spectrometers and with mass spectrometers. In ... It is headquartered in Billerica, Massachusetts and is the publicly traded parent company of Bruker Scientific Instruments ( ...
"Analysis of Amphetamine-Derived Designer Drugs by Gas Chromatography with Mass Spectrometry". Journal of Analytical Toxicology ...
Gas or liquid chromatography and mass spectrometry (e.g. LC-MS/MS) achieves greater specificity than immunoassays. Measurement ...
Sterol levels are measured by gas chromatography-mass spectrometry. Genetic screening for Conradi-Hünermann syndrome via the ...
"Gas Chromatography-Mass Spectrometry". American Chemical Society. Retrieved 19 November 2019.. *^ D.Sc, F. W. Aston M. A. (1 ... KM Downard (2007). "Francis William Aston - the man behind the mass spectrograph". European Journal of Mass Spectrometry. 13 (3 ... "Mass Spectrometry Reviews. 26 (5): 713-723. Bibcode:2007MSRv...26..713D. doi:10.1002/mas.20145. PMID 17546675.. ... Kevin M. Downard (2015). "Francis William Aston". The Encyclopedia of Mass Spectrometry. 9B. pp. 6-8. doi:10.1016/B978-0-08- ...
"Early gas chromatography/mass spectrometry". Journal of the American Society for Mass Spectrometry. 4 (5): 367-371. doi:10.1016 ... He took a position at Dow Chemical in Midland, Michigan in 1950 and was in charge of mass spectrometry and gas chromatography ... "Gas Chromatography-Mass Spectrometry". American Chemical Society. Retrieved 19 Nov 2019. Gohlke, Roland S.; McLafferty, Fred W ... With Roland Gohlke, he pioneered the technique of gas chromatography-mass spectrometry. He is also known for electron capture ...
"Analysis of triacetone triperoxide by gas chromatography/mass spectrometry and gas chromatography/tandem mass spectrometry by ... including gas chromatography/mass spectrometry (GC/MS),[14][15][16][17][18] high performance liquid chromatography/mass ... "Surface-sampling and analysis of TATP by swabbing and gas chromatography/mass spectrometry". Forensic Science International. ... and TATP synthetic intermediates by electrospray ionization mass spectrometry". Rapid Communications in Mass Spectrometry. 22 ( ...
"Doping control for metandienone using hair analyzed by gas chromatography-tandem mass spectrometry". J. Chromatogr. B. 836 (1-2 ... Mass spectrometry is also used to detect small samples of nandrolone in urine samples, as it has a unique molar mass. ...
Analysis using gas chromatography and mass spectrometry has been used to identify bioactive compounds in essential oils. These ... Adams, Robert P. (2007). Identification of Essential Oil Components by Gas Chromatography/Mass Spectrometry. Barrett, S. " ... ISBN 0-12-227055-X.[page needed] Cather, JC; MacKnet, MR; Menter, MA (2000). "Hyperpigmented macules and streaks". Proceedings ...
They used gas chromatography and gas chromatography/mass spectrometry methods. It was found that the flowers of Iris kerneriana ...
"Cinnamaldehyde content in foods determined by gas chromatography-mass spectrometry". Journal of Agricultural and Food Chemistry ... Lay summary - Science Daily (July 16, 2004). Ma, W.-B.; Feng, J.-T.; Jiang, Z.-L.; Zhang, X. (2014). "Fumigant Activity of 6 ...
Sperm whale oil analysis by gas chromatography and mass spectrometry. Journal of the American Oil Chemists' Society J.W. ... Alkoxy-Acyl Combinations in the Wax Esters from Winterized Sperm Whale Oil by Gas Chromatography-Mass Spectrometry " ... causing it to congeal into a spongy and viscous mass. The congealed matter was then loaded into wool sacks and placed in a ...
Niessen, Wilfried M.A. (2001). Current Practice of gas chromatography-mass spectrometry (1 ed.). pp. 55-94. Chosson, P; Lanau, ... The techniques typically used includes gas chromatography and mass spectrometry. Petroleum biomarkers are highly important in ... "Petroleum biomarkers analyzed by atmospheric gas chromatography-tandem mass spectroscopy" (PDF). Waters. Osadetz, K.G; ... Most biomarkers also usually have high molecular mass. Some examples of biomarkers found in petroleum are pristane, triterpanes ...
"Determination of MDPBP in postmortem blood samples by gas chromatography coupled with mass spectrometry". Monatshefte für ...
"Alcohol Tax and Trade Bureau "Screening of Distilled Spirits for Thujone by Gas Chromatography-Mass Spectrometry". Alcohol and ... This is verified through the use of gas chromatography-mass spectrometry. The brands Kübler and Lucid and their lawyers did ... β-Thujone and Related Terpenes in Absinthe using Solid Phase Extraction and Gas Chromatography" (PDF). Deutsche Lebensmittel- ... By the 1880s, mass production had caused the price to drop sharply, and the French were drinking 36 million litres per year by ...
"Detection of DEHP in beverages sold in Canada using gas chromatography-mass spectrometry". Bcit Environmental Health Journal. ...
Gas chromatography/mass spectrometry analysis of the essential oil revealed the presence of trans-anethole (21.1%), α-trans- ... Louis, MO & Harvard University Herbaria, Cambridge, MA. Lin, Yourun; Humphries, Christopher J.; Gilbert, Michael G. "Artemisia ... Louis, MO & Harvard University Herbaria, Cambridge, MA. "Artemisia dracunculus L.". Flora of Pakistan. Missouri Botanical ...
A New Highly Sensitive Approach for Liquid Chromatography/Mass Spectrometry of Small and Large Molecules". Analytical Chemistry ... a New Atmospheric Pressure MALDI Method for Producing Highly Charged Gas-phase Ions of Peptides and Proteins Directly from ... Trimpin, Sarah (2015). ""Magic" Ionization Mass Spectrometry". Journal of the American Society for Mass Spectrometry. 27 (1): 4 ... In mass spectrometry, matrix-assisted ionization (also inlet ionization) is a low fragmentation (soft) ionization technique ...
One of the first to use gas chromatography, mass spectrometry and thin layer chromatography in flavor research, Patton proved, ...
... cannabinol and cannabidiol in samples of cannabis by combined gas chromatography and mass spectrometry". The Journal of ...
and ion microscopy (SIMS) but not gas chromatography. This definition also appears in some mass spectrometry texts. There are ... "resolving power in mass spectrometry". doi:10.1351/goldbook.R05321 Biemann, Klaus (1962). Mass Spectrometry: Organic Chemical ... In mass spectrometry, resolution is a measure of the ability to distinguish two peaks of slightly different mass-to-charge ... This definition is used in a number of mass spectrometry texts. This use is also implied by the term "high-resolution mass ...
... and Gas chromatography-mass spectrometry (GCMS) analyses. The API gravity of the oils ranges from 35° to 62° and sulfur ... The zone of wet gas generation is in the 1.1-1.4% Ro range, whereas the primary zone of dry gas generation (main gas window) ... Continuous-type accumulations include fractured shale and fractured limestone oil and gas, basin-centered gas, coal bed gas, ... of gas, and 500 million barrels (79×10^6 m3) of natural gas liquids. Cumulative gas production from the Barnett Shale for the ...
Yu, J.; Baeten, A.; Citrowske, S. "Quantification of Tentatively Identified Extractables and Leachables with Mass Spectrometry ... Oil, Gas, and Biofuels: The Polyarc system can dramatically simplify the calibration process by reducing (or eliminating) the ... Watanabe, T., Kato, K., Matsumoto, N., and Maeda, T., Chromatography, 27 (2006) 1-7. Watanabe, T., Kato, K., Matsumoto, N., and ... The reactor is paired with a flame ionization detector (FID) in a gas chromatograph (GC) to improve the sensitivity of the FID ...
... Residues in Vegetables Using Dispersive-SPE Sample Preparation Combined with Gas Chromatography-Mass Spectrometry ...
... library using liquid chromatography with photodiode array spectrophotometry detector and gas chromatography-mass spectrometry ...
... cutoffs were 50 ng/mL for an initial immunoassay test and 15 ng/mL for a confirmatory gas chromatography-mass spectrometry test ... and Massachusetts. A major US insurance company states that "there are no widely accepted methods for detecting impairment from ...
For metabolite profiling, gas chromatography-mass spectrometry is used to find flavonoids such as quercetin. Compounds can then ... They are generally isolated and measured through the use of chromatography and mass spectrometry techniques. Additionally, the ... Chemical compounds are then derived through various chromatography and mass spectrometry separations. However, extraction ... be further differentiated using reversed-phase high-performance liquid chromatography-mass spectrometry. When it comes to ...
"Ultrasonic nebulization extraction coupled with headspace single drop microextraction and gas chromatography-mass spectrometry ...
... of gas phase triacetone triperoxide with aspiration ion mobility spectrometry and gas chromatography-mass spectrometry". ... but are often coupled with mass spectrometry, gas chromatography or high-performance liquid chromatography in order to achieve ... When IMS is used with mass spectrometry, ion mobility spectrometry-mass spectrometry offers many advantages, including better ... 2005). "Ion mobility-mass spectrometry: a new paradigm for proteomics". International Journal of Mass Spectrometry. 240 (3): ...
... yohimbe bark with ultra-performance liquid chromatography coupled with ion mobility quadrupole time-of-flight mass spectrometry ... Betz JM, White KD, der Marderosian AH (1995). "Gas chromatographic determination of yohimbine in commercial yohimbe products". ... However, in 1972, Effler and Effler using modern analytical techniques, including mass spectrometry, UV absorption, IR ... Rapid Communications in Mass Spectrometry. 25 (18): 2591-602. doi:10.1002/rcm.5158. PMID 23657953. Cohen PA, Wang YH, Maller G ...
... breast milk and tissues by gas chromatography-mass spectrometry using selected ion monitoring". Journal of Chromatography B. ...
... identification of anabasine by gas-chromatography/mass spectrometry". Journal of Forensic Sciences. 45 (3): 736-41. doi:10.1520 ...
For example, using mass spectrometry on plant protein mixtures would result in multiple intense RuBisCO subunit peaks that ... Journal of Chromatography B. 861 (1): 29-39. doi:10.1016/j.jchromb.2007.11.024. PMID 18063427. Agrawal GK, Jwa NS, Rakwal R ( ... since these reactions require CO 2 to pass by gas exchange through these openings. Evaporation through the upper side of a leaf ... Parry MA, Andralojc PJ, Mitchell RA, Madgwick PJ, Keys AJ (May 2003). "Manipulation of Rubisco: the amount, activity, function ...
... emission spectroscopy Inductively coupled plasma atomic emission spectroscopy Inductively coupled plasma mass spectrometry LBOZ ... By running an affinity chromatography, B-Galactosidase can be isolated and tested by reacting collected samples with ONPG and ... or gases. Although many biochemicals are colored, as in, they absorb visible light and therefore can be measured by ...
... of indigoid compounds present in archaeological Maya blue by pyrolysis-silylation-gas chromatography-mass spectrometry. Journal ... MA: Interlink Publishing Group. ISBN 978-1-56656-795-4. "Chicanná Ruins." Locogringo. N.p., n.d. Web. 26 Feb. 2015. . Potter, ...
"Gas Chromatography-Mass Spectrometry". American Chemical Society. Retrieved 19 November 2019. "Nobel Winner Archer Martin Dies ... "Gas-Liquid Chromatography: A Technique for the Analysis and Identification of Volatile Materials" reported the discovery of gas ... He developed partition chromatography whilst working on the separation of amino acids, and later developed gas-liquid ... JAMES, AT; MARTIN, AJ (1954). "Gas-liquid chromatography; a technique for the analysis and identification of volatile materials ...
... chromatography and imaging methods". Rapid Communications in Mass Spectrometry. 28 (16): 1779-1791. doi:10.1002/rcm.6960. ISSN ... the gas-phase acidity of the protonated water clusters and the gas-phase basicity of the analyte molecule are of crucial ... "Paint Spray Mass Spectrometry for the Detection of Additives from Polymers on Conducting Surfaces". Mass Spectrometry Letters. ... "Mass spectrometry imaging under ambient conditions". Mass Spectrometry Reviews. 32 (3): 218-243. Bibcode:2013MSRv...32..218W. ...
Thermal desorption for gas chromatography, in: Gas Chromatography, ed. C.F. Poole, Elsevier, 2012, chapter 10, pp. 235-289; ... Journal of Mass Spectrometry. 2004 (39): 233-254. doi:10.1002/jms.606. PMID 15039931. A.-L. Sunesson, Passive sampling in ... MDHS 80, Laboratory method using diffusive solid sorbent tubes, thermal desorption and gas chromatography, UK Health & Safety ... Purge-and-trap - A flow of gas is bubbled through an aqueous sample (a beverage or aqueous extract), and the gas stream then ...
... by gas chromatography/mass spectrometry and liquid chromatography/quadrupole time-of-flight mass spectrometry". Rapid ... plasma or urine by gas chromatography-mass spectrometry or liquid chromatography-mass spectrometry to confirm a diagnosis of ... Journal of Mass Spectrometry. 45 (12): 1426-42. Bibcode:2010JMSp...45.1426M. doi:10.1002/jms.1859. PMID 21053377. Baselt RC ( ... Until it was banned in 2011, products containing MDPV and labeled as bath salts were sold as recreational drugs in gas stations ...
... pig fat by means of stable isotope dilution analysis-headspace solid-phase microextraction-gas chromatography/mass spectrometry ...
... which before the introduction of the Gas Chromatography-Mass Spectrometry assay, could not be identified in athletes' samples. ...
... is also commonly used as a polar stationary phase for gas chromatography, as well as a heat transfer fluid ... PEG is often used (as an internal calibration compound) in mass spectrometry experiments, with its characteristic fragmentation ... Mw and Mn can be measured by mass spectrometry. PEGylation is the act of covalently coupling a PEG structure to another larger ... PEO to polymers with a molecular mass above 20,000 g/mol, and POE to a polymer of any molecular mass. PEGs are prepared by ...
Resonance-Ionization Mass Spectrometry of Carbon', Journal of the Optical Society of America B, vol. 2, no. 9, pp. 1561-5, doi: ... Gas! Gas! Gas!', New Scientist, vol. 228, no. 3044, pp. 34-37 Madelung O 2004, Semiconductors: Data Handbook, 3rd ed., Springer ... Ion Chromatography, John Wiley & Sons, New York, ISBN 3-527-61325-0 Gary S 2013, 'Poisoned Alloy' the Metal of the Future', ... Ma Y, Ma Y, Glass CW, Liu Z, Yu T, Kurakevych OO & Solozhenko VL 2009, 'Ionic High-Pressure Form of Elemental Boron', Nature, ...
... such as ion-exchange chromatography and gas chromatography-mass spectrometry. They synthesized 33 amino acids, including 10 ... such as high-performance liquid chromatography and liquid chromatography-time of flight mass spectrometry. Their result showed ... From spectroscopic observations on stars, it is now well known that complex organic compounds are formed in the gases blown off ... With persistence Miller persuaded Urey to pursue electric discharges in gases. He found clear evidence for the production of ...
Gas chromatography-mass spectrometry (GC-MS) is an analytical method that combines the features of gas-chromatography and mass ... "Early gas chromatography/mass spectrometry". Journal of the American Society for Mass Spectrometry. 4 (5): 367-371. doi:10.1016 ... Amirav A, Gordin A, Poliak M, Fialkov AB (2008). "Gas chromatography-mass spectrometry with supersonic molecular beams". J Mass ... Gas chromatography-mass spectrometry. *Liquid chromatography-mass spectrometry. *Pyrolysis-gas chromatography-mass spectrometry ...
MS helps fragment the components and identify them on the basis of their mass. ... Gas chromatography-mass spectrometry (GC-MS) is a hybrid analytical technique that couples the separation capabilities of GC ... www.thermofisher.com/ca/en/home/industrial/mass-spectrometry/gas-chromatography-mass-spectrometry-gc-ms.html ... Gas chromatography-mass spectrometry (GC-MS) is a hybrid analytical technique that couples the separation capabilities of GC ...
The sample is injected into the GC inlet where it is vaporized and eluted on a chromatographic column by the carrier gas, ... Gas Chromatography coupled with Mass Spectrometry is a widely used technique for the analysis and quantification of organic ... Gas Chromatography coupled with Mass Spectrometry is a widely used technique for the analysis and quantification of organic ... The sample is injected into the GC inlet where it is vaporized and eluted on a chromatographic column by the carrier gas, ...
Gas chromatography mass spectrometry-based metabolite profiling in plants.. Lisec J1, Schauer N, Kopka J, Willmitzer L, Fernie ... Corrigendum: Gas chromatography mass spectrometry-based metabolite profiling in plants. [Nat Protoc. 2015] ... Here we provide a detailed protocol for gas chromatography mass spectrometry (GC-MS)-based metabolite profiling that offers a ... being considerably more sensitive than NMR and more robust than liquid chromatography-linked mass spectrometry. We summarize ...
the quantitative and qualitative analysis by gas chromatography and mass spectrometry (GC-MS) as well as sensorial assays are ... and gas chromatography/mass spectrometry (GC/MS HP-5890). Twenty volatile compounds were identified in the extracts among them ... composition of tomato during storage by a combination sampling method coupled with gas chromatography/mass spectrometry. Jäger ... A HewlettPackard 5890 Series II gas chromatograph with flame ionization detector (FID) coupled to 5972 MSD quadrupole mass ...
Fast Gas Chromatography with Tandem Mass Spectrometry Analysis of Selected Persistent Organic Pollutants and Organophosphorus ... "Fast Gas Chromatography with Tandem Mass Spectrometry Analysis of Selected Persistent Organic Pollutants and Organophosphorus ...
Capillary electrophoresis-mass spectrometry Ion-mobility spectrometry-mass spectrometry Liquid chromatography-mass spectrometry ... Gas chromatography-mass spectrometry (GC-MS) is an analytical method that combines the features of gas-chromatography and mass ... "Early gas chromatography/mass spectrometry". Journal of the American Society for Mass Spectrometry. 4 (5): 367-71. doi:10.1016/ ... "Gas chromatography-mass spectrometry with supersonic molecular beams". Journal of Mass Spectrometry. 43 (2): 141-63. Bibcode: ...
Fatty acid composition of human erythrocyte membranes by capillary gas chromatography-mass spectrometry.. Alexander LR, Justice ... Capillary gas chromatographic and gas chromatographic--mass spectrometric methods were employed for profiling total fatty acid ... Confirmation of identities by mass spectral structure elucidation revealed saturated, mono- and polyunsaturated, and branched- ...
Gas Chromatography Mass Spectrometry. Filed Under: Criminal Law; Forensic Science; Health Law; Medical Law & Legislation; ...
"Hyphenation of aqueous liquid chromatography to pyrolysis-gas chromatography and mass spectrometry for the comprehensive ... Pyrolysis-gas chromatography-mass spectrometry is a method of chemical analysis in which the sample is heated to decomposition ... "Derivatization in mass spectrometry --7. On-line derivatisation/degradation". European Journal of Mass Spectrometry. 12 (1): 1- ... to produce smaller molecules that are separated by gas chromatography and detected using mass spectrometry. Pyrolysis is the ...
Gas chromatography-mass spectrometry (GC-MS) analysis of extractives of naturally durable wood. In: Proceedings, one hundred ... Gas chromatography-mass spectrometry (GC-MS) analysis of extractives of naturally durable wood ... mass spectrometry, gas chromatography, deterioration, chemical composition, wood variation, resistance to decay, durability, ... study to evaluate naturally durable wood species in an above ground field trial using Gas Chromatography-Mass Spectrometry (GC- ...
Principles and instrumentation of gas chromatography-mass spectrometry. In: Current practice of gas chromatography-mass ... Gas Chromatography-Mass Spectrometry (GC-MS). *Patricia M. MedeirosAffiliated withDepartment of Marine Sciences, University of ... Gas Chromatography-Mass Spectrometry (GC-MS). Reference Work Title. Encyclopedia of Geochemistry Reference Work Subtitle. A ... Gas chromatography-mass spectrometry (GC-MS) is one of the so-called hyphenated analytical techniques. It is actually two ...
... in different stages of development by gas chromatography and gas chromatography-mass spectrometry. Journal of Chromatography. A ... isotope dilution and gas chromatography-mass spectrometry: Review. Journal of Chromatography B, 758(1), 3-25.CrossRefGoogle ... and hyphenated techniques such as gas chromatography (GC) and liquid chromatography (LC) coupled to mass spectrometry (MS). In ... Higher mass loadability in comprehensive two-dimensional gas chromatography-mass spectrometry for improved analytical ...
An EI/CI GC-MS/MS mass spectrometry system that is robust by design and engineered to maximize uptime. Developed to withstand ... Mass Spectrometry , Tandem Quadrupole ( Triple Quadrupole ) Mass Spectrometry , Xevo TQ-GC Mass Spectrometry System ... Xevo TQ-GC Mass Spectrometry System. The perfect addition to your laboratory. A robust EI and CI GC-MS/MS platform engineered ... Reduce business risks and make your laboratory more productive with the Xevo TQ-GC mass spectrometer. Watch the Video ...
... and mass spectrometry (MS) to the extent necessary to understand and deal... ... The book begins by covering the basic principles of both gas chromatography (GC) ... 4. Gas Chromatography-Mass Spectrometry. Vacuum and gas flow: basic principles, analysis of vacuum and gas flow, interfaces. ... The software package Gas Chromatography-Mass Spectrometry: A Knowledge Base, by F.A. Settle, Jr. and M.A. Pleva provides rapid ...
... Sawsan Daher ... in the New Zealand manuka honey was carried out by solid phase microextraction followed by gas chromatography-mass spectrometry ... Laboratory of Mass SpectrometryPhysical Chemistry, University of Geneva, Sciences I, Boulevard dIvoy 16, CH-1211 Geneva 4, ... Their structures were deduced from the mass spectral data. Seven other compounds; 2,3-dimethoxynaphthalene, 4-(x-methoxyphenyl ...
A gas chromatography/mass spectrometry system based on the combination of an automated vapor sample inlet, a transfer l ... A portable gas chromatography/mass spectrometry system was developed for use in situations where site location, contamination, ... A gas chromatography/mass spectrometry system based on the combination of an automated vapor sample inlet, a transfer line gas ... A portable gas chromatography/mass spectrometry system was developed for use in situations where site location, contamination, ...
Chromatography, Gas-Liquid-Mass Spectrometry*Chromatography, Gas-Liquid-Mass Spectrometry. *Chromatography, Gas Liquid Mass ... "Gas Chromatography-Mass Spectrometry" by people in Harvard Catalyst Profiles by year, and whether "Gas Chromatography-Mass ... Gas Chromatography-Mass Spectrometry*Gas Chromatography-Mass Spectrometry. *Chromatography-Mass Spectrometry, Gas ... Gas-Liquid Chromatography-Mass Spectrometry. *Chromatography-Mass Spectrometry, Gas-Liquid. *Gas Liquid Chromatography Mass ...
... using gas chromatography combined with low resolution mass spectrometry (GC-MS). It is based on direct n-hexane solid-liquid ... "Direct Determination of Polychlorinated-Biphenyls in Automotive Shredder Residues by Gas Chromatography-Mass Spectrometry" ...
Our gas chromatography mass spectrometry (GC-MS) instrumentation are suited for most any applications for food, environmental, ... Method 8260C by Purge and Trap Gas Chromatography Mass Spectrometry using the Clarus SQ 8 ... Method 8260C by Purge and Trap Gas Chromatography Mass Spectrometry using the Clarus SQ 8 ... Todaylj labs need and want more from their chromatography so many have turned to mass spectrometry for greater insights and ...
... anhydride and analyzed by gas chromatography/mass spectrometry using electron ionization in positive mode. Gas chromatographic ... Further prominent fragment ions at ,i ,m/z,/i, 118 for MA and AM, ,i ,m/z,/i, 162 for MDMA, MDEA, and MDA, and ,i ,m/z,/i, 176 ... Base peaks or prominent peaks of MA, AM, MDMA, MDEA, MBDB, MDA, and BDB appeared at ,i ,m/z,/i, 154, 140, 154, 168, 168, 135, ... MA), amphetamine (AM), and the methylenedioxyphenylalkylamine designer drugs, such as 3,4-methylenedioxymethamphetamine (MDMA ...
... gas chromatography mass spectrometry (GC-MS) systems enable identification of volatile and semi-volatile compounds at trace ... Thermo Scientific gas chromatography mass spectrometry systems provide complete solutions to the most challenging applications ... Experience enhanced high-resolution mass spectrometry with our easy-to-use magnetic sector GC-MS systems. ... Our Orbitrap mass analyzer mass spectrometers offer unparalleled performance, sensitivity and dynamic range for the most ...
Method 8260C by Purge and Trap Gas Chromatography Mass Spectrometry using the Clarus SQ 8 ... Method 8260C by Purge and Trap Gas Chromatography Mass Spectrometry using the Clarus SQ 8 ... 1/16", 10-Port Gas Sample Valve with T rotor N9302816 This external sample injector features 10 ports and has a fitting size of ... This switching valve allows employment of different desired mobile phases by periodically injecting into the carrier gas stream ...
... of Organic Acids in Used Engine Oil Residues by Pyrolysis-Comprehensive 2D Gas Chromatography-Time of Flight Mass Spectrometry ... of Organic Acids in Used Engine Oil Residues by Pyrolysis-Comprehensive 2D Gas Chromatography-Time of Flight Mass Spectrometry ... was then analyzed using pyrolysis-comprehensive two dimensional gas chromatography with time-of-flight mass spectrometry. ...
Validation of a gas chromatography/triple quadrupole mass spectrometry based method for the quantification of pesticides in ... Validation of a gas chromatography/triple quadrupole mass spectrometry based method for the quantification of pesticides in ... Rapid Communications in Mass Spectrometry. Volume 20, Issue 3, pages 365-375, 15 February 2006 ...
Purchase Advanced Techniques in Gas Chromatography-Mass Spectrometry (GC-MS-MS and GC-TOF-MS) for Environmental Chemistry, ... Advanced Techniques in Gas Chromatography-Mass Spectrometry (GC-MS-MS and GC-TOF-MS) for Environmental Chemistry, Volume 61 1st ... Gas chromatography mass spectrometry (GC-MS) has been the technique of choice of analytical scientists for many years. The ... Advanced Techniques in Gas Chromatography-Mass Spectrometry (GC-MS-MS and GC-TOF-MS) for Environmental Chemistry ...
Method using gas chromatography-mass spectrometry (GC-MS) after phenylation and solvent extraction ... Water quality - Determination of alkylmercury compounds in water - Method using gas chromatography-mass spectrometry (GC-MS) ...
... gas chromatography coupled to mass spectrometry (GC-MS) 2018-36-0063. A visible exudation of additives on Thermoplastic ... and Gas Chromatography Coupled to Mass Spectrometry (GC-MS). A comparison between retention times of solvent containing ... gas chromatography coupled to mass spectrometry(GC-MS)," SAE Technical Paper 2018-36-0063, 2018, https://doi.org/10.4271/2018- ...
Identification of N-Nitrosodimethylamine in Ambient Air by Capillary Gas-liquid Chromatography Mass Spectrometry-Computer. ... Identification of N-Nitrosodimethylamine in Ambient Air by Capillary Gas-liquid Chromatography Mass Spectrometry-Computer. ...
  • Like liquid chromatography-mass spectrometry , it allows analysis and detection even of tiny amounts of a substance. (wikipedia.org)
  • Global Gas Chromatography , Liquid Chromatography , Mass Spectrometry and Spectroscopy Instruments Market 2019 Report provides main statistics connected to the overall market and price forecast over a period, from 2019 to 2028. (wn.com)
  • The report gives the research-based overview of on Global Gas Chromatography, Liquid Chromatography, Mass Spectrometry and Spectroscopy Instruments Market 2019 size, industry status and forecast, competition landscape and growth opportunity. (pharmiweb.com)
  • This research report categorizes the global gas chromatography, liquid chromatography, mass spectrometry and spectroscopy instruments market by companies, region, type and end-use industry. (pharmiweb.com)
  • The worldwide gas chromatography, liquid chromatography, mass spectrometry and spectroscopy instruments market report intensely underlines essential market fragments including types, Key developments, driving commercial centres dependent on topographical regions, key organizations, and innovations. (pharmiweb.com)
  • This report focuses on the gas chromatography, liquid chromatography, mass spectrometry and spectroscopy instruments in the global market, especially in North America, Europe, Asia-Pacific, Latin America, Middle East and Africa . (pharmiweb.com)
  • It provides current and future trends are outlined to determine the overall attractiveness and to single out profitable trends to pick up a stronger foothold in the gas chromatography, liquid chromatography, mass spectrometry and spectroscopy instruments industry. (pharmiweb.com)
  • This report studies the gas chromatography, liquid chromatography, mass spectrometry and spectroscopy instruments status and outlook of Global and Major Regions, from angles of players, countries, product types and end industries and also analyzes the top players in the global market, and splits the Gas Chromatography, Liquid Chromatography, Mass Spectrometry and Spectroscopy Instruments by product type and applications/end industries. (pharmiweb.com)
  • 1. The primary objective of the study is to understand and gain insights about the global gas chromatography, liquid chromatography, mass spectrometry and spectroscopy instruments market and its segmental analysis by type, by application and by region. (pharmiweb.com)
  • 2. To identify major trends in the global gas chromatography, liquid chromatography, mass spectrometry and spectroscopy instruments market. (pharmiweb.com)
  • 3. To study and forecast the market size of gas chromatography, liquid chromatography, mass spectrometry and spectroscopy instruments in the worldwide market. (pharmiweb.com)
  • This system is available for the analysis of compounds not amenable to liquid-chromatography-mass spectrometry. (elsevier.com)
  • Combined gas-liquid chromatography-mass spectrometry is used to identify unequivocally the molecular structure of modified amino acids. (springer.com)
  • N(ε)-(2-Carboxyethyl)lysine was detected by the combined gas-liquid chromatography-mass spectrometry in the hydrolyzate of reduced wool treated with acrylonitrile. (springer.com)
  • In addition, polar substances will require liquid chromatography-mass spectrometry analysis, the method for which will be developed soon. (diva-portal.org)
  • The first on-line coupling of gas chromatography to a mass spectrometer was reported in 1959. (wikipedia.org)
  • In 1964, Electronic Associates, Inc. (EAI) , a leading U.S. supplier of analog computers, began development of a computer controlled quadrupole mass spectrometer under the direction of Robert E. Finnigan . (wikipedia.org)
  • The GC-MS is composed of two major building blocks: the gas chromatograph and the mass spectrometer . (wikipedia.org)
  • The molecules are retained by the column and then elute (come off) from the column at different times (called the retention time), and this allows the mass spectrometer downstream to capture, ionize, accelerate, deflect, and detect the ionized molecules separately. (wikipedia.org)
  • The mass spectrometer does this by breaking each molecule into ionized fragments and detecting these fragments using their mass-to-charge ratio. (wikipedia.org)
  • Sometimes two different molecules can also have a similar pattern of ionized fragments in a mass spectrometer (mass spectrum). (wikipedia.org)
  • Combining the two processes reduces the possibility of error, as it is extremely unlikely that two different molecules will behave in the same way in both a gas chromatograph and a mass spectrometer. (wikipedia.org)
  • A HewlettPackard 5890 Series II gas chromatograph with flame ionization detector (FID) coupled to 5972 MSD quadrupole mass spectrometer was used. (scribd.com)
  • Reduce business risks and make your laboratory more productive with the Xevo TQ-GC mass spectrometer. (waters.com)
  • The operator would wear a harness to support the mass spectrometer and computer in front of him. (cdc.gov)
  • The mass spectrometer breaks each molecule into ionized fragments and sorts the ions based on their mass-to-charge ratio. (niom.no)
  • Two different substances may also have a similar pattern of ionized fragments when using a mass spectrometer, as shown in the mass spectra of Diethyleneglycol dimethacrylate and Triethyleneglycoldimethacrylate, but often have different retention times. (niom.no)
  • Since its first bench-top gas chromatograph/mass spectrometer (GC-MS) was sold in 1979, Shimadzu has been a leader in design innovations, such as our front access ion source, high efficiency ion optics, 20,000 u/second scan speed, and post-quadrupole focusing lenses. (shimadzu.com)
  • The low-molecular weight organic compounds (LMWOC) of the extracts were defined by methods of GC/MS with the help of Shimadzu GC/MS (QP-5050А, Shimadzu, Japan) equipped with the software Class 5000 and chromato-mass spectrometer TRACE DSQ II (Thermo Electron Corporation) with quadrupole mass analyser. (ijpsonline.com)
  • A sensitive method has been developed for the trace analysis of alkyl alkylphosphonic acids, metabolites of nerve agents, in urine using a benchtop ion trap mass spectrometer. (biomedsearch.com)
  • An ion trap mass spectrometer in selected reaction monitoring mode provided limits of detection of 0.1 ng/ml for isopropyl, isobutyl, pinacolyl and cyclohexyl methylphosphonic acids and for ethyl ethylphosphonic acid. (biomedsearch.com)
  • As a sample constituent elutes from the GC column, it enters the ionization chamber of the mass spectrometer where the molecules are ionized, typically by electron impact. (mee-inc.com)
  • Next Generation quadrupole Mass Spectrometer with membrane inlet. (bruker.com)
  • This work evaluated the performance of 2D LC variant using a QToF setup instead of a triple quadrupole mass spectrometer for the analysis of drug of abuse in urine targeting low and sub ppb level. (technologynetworks.com)
  • GC/MS is a tandem technology, utilizing a gas chromatograph coupled to a mass spectrometer. (booksie.com)
  • Adopting a proprietary multi-function ion source, large-capacity turbomolecular pump with heightened exhaust efficiency for all carrier gases, including nitrogen, and Advanced Scanning Speed Protocol, the GCMS-QP2020 NX can assist any laboratory, regardless of its GC-MS application focus, achieve its full potential. (shimadzu.com)
  • Dynamic headspace, using gas chromatography-mass spectrometry (DHS/GCMS), was used to identify volatile compounds at three different temperatures. (ajol.info)
  • Derivatization in mass spectrometry --7. (wikipedia.org)
  • Because of their relatively low molecular weights, high polarity, and volatility, derivatization is necessary when using gas chromatography (GC) [ 9 ]. (hindawi.com)
  • Although quantitative analysis of MA, AM, and the methylenedioxyphenylalkylamine designer drugs has been frequently performed in clinical and forensic toxicology by GC/MS-EI with derivatization [ 8 , 12 - 17 ], systematic studies of mass spectrometric behavior for these compounds have been limited [ 9 , 18 , 19 ]. (hindawi.com)
  • Also included are basic information on instrumentation, ionization methods, quantitation, tips on the operation of mass spectrometers, the best derivatization procedures for a variety of compound types, troubleshooting techniques, and a variety of other information found to be useful to the practicing user of GC/MS instrumentation. (mexmat.ru)
  • A method was developed for quantitative determination of the non-protein amino acid, dencichine, in plant samples of P. notoginseng and the adventitious roots directly from the explants of P. notoginseng after derivatization with ethyl chloroformate (ECF) by gas chromatography-mass spectrometry (GC-MS). l-2-chlorophenylalanine was used as an internal standard. (uncg.edu)
  • Analysis of nonylphenol polyethoxycarboxylates and their related metabolites by on-line derivatization and ion-trap gas chromatography-mass spectrometry. (semanticscholar.org)
  • This residue was then analyzed using pyrolysis-comprehensive two dimensional gas chromatography with time-of-flight mass spectrometry. (sae.org)
  • Harvath, P., Reidy, S., and Byer, J., "Identification of Organic Acids in Used Engine Oil Residues by Pyrolysis-Comprehensive 2D Gas Chromatography-Time of Flight Mass Spectrometry," SAE Technical Paper 2016-01-2274, 2016, https://doi.org/10.4271/2016-01-2274 . (sae.org)
  • Quantify and screen samples with a single injection using LECO Two-Dimensional Gas Chromatography Time-of-Flight Mass Spectrometry (GC×GC TOFMS). (leco.com)
  • The aim of this work was to assess the suitability of matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) for routine heterotrophic monitoring in a drinking water treatment plant. (environmental-expert.com)
  • Here, methods were developed that utilize gas chromatography (GC) to separate individual analyte components from each other and time-of-flight mass spectrometry (TOFMS) for identification of the individual analytes. (technologynetworks.com)
  • Comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GCxGC/TOF-MS) has been used for metabolite profiling in metabolomics. (biomedcentral.com)
  • Heisterkamp, M. and Adams, F.C. (2001) Gas chromatography-inductively coupled plasma-Time-of-flight mass spectrometry for the speciation analysis of organolead compounds in environmental water samples. (hanspub.org)
  • Quantitative Amino Acid Analysis by Gas Chromatography. (springer.com)
  • The application of gas chromatography (GC) combined with atmospheric pressure chemical ionization mass spectrometry (GC-APCI-MS) and with supersonic molecular beam ionization mass spectrometry (GC-SMB-MS). (chromatographyonline.com)
  • For Solid Phase Micro Extraction (SPME) , it is an equilibrium sampling method and can be used for gases, solids (Headspace) and liquids (direct). (utm.my)
  • The potential of selected ion flow tube mass spectrometry (SIFT-MS) to differentiate malted barley cultivars on the basis of their headspace profiles has been investigated. (ebscohost.com)
  • collected from two different geographic regions by headspace solid-phase microextraction (HS-SPME), combined with gas chromatography/mass spectrometry (GC/MS). The volatile components included some. (ebscohost.com)
  • In this paper, a method based on headspace solid-phase microextraction (HSâ€"SPME) coupled with gas chromatographyâ€"mass spectrometry. (ebscohost.com)
  • This dynamic extraction method has superior sensitivity to solid phase micro extraction, SPME and is capable of extracting the entire gas phase by purging the headspace of a vial. (go.jp)
  • Volatiles produced from Sleeman Cream Ale during aging for up to 28 days at -1 C were sampled periodically and monitored by a trained sensory panel, by headspace analysis with an electronic nose (EN), and by solid phase microextraction coupled with gas chromatography-mass spectrometry. (mbaa.com)
  • la cerveza se degust peri dicamente por un panel de degustaci n entrenado, se le practic un analisis del espacio gaseoso ("headspace analysis") con una nariz electr nica (NE) y se analiz por microextracci n en fase s lida junto con cromatograf a de gases y espectrometr a de masa. (mbaa.com)
  • Most of these procedures are based on established sample preparation and analytical techniques employing high resolution gas chromatography/ high resolution mass spectrometry (HRGC/HRMS), which are used for the analyses of dioxin/furans at low parts-per-trillion (ppt) levels. (epa.gov)
  • Extract quantification is accomplished by computer-assisted high-resolution gas chromatography (HRGC) used in conjunction with a procedural recovery mixture containing perdeuterated compounds of differing polarity and molecular weight. (caltech.edu)
  • Routine quality control analysis is performed on a per-sample basis by high-resolution gas chromatography/mass spectrometry (HRGC/MS) for confirmation of the standard components and for identification of procedural contaminants. (caltech.edu)
  • Major chemical features of the solvent-soluble organic aerosol carbon fraction (i.e., carbon range C_8-C_(36)) are quantified and identified by high-resolution gas chromatography (HRGC) and high-resolution gas chromatography / mass spectrometry (HRGC / MS). Through these methods, bulk characteristics of the atmospheric aerosol are denned and reveal information relating to seasonal variations and specific source contributions to the atmospheric organics complex mixture. (caltech.edu)
  • Sediment and soil samples are extracted using a microwave-assisted extraction system, and the pyrethroids of interest are separated from co-extracted matrix interferences by passing the extracts through stacked graphitized carbon and alumina SPE cartridges, along with the use of high-performance liquid chromatography and gel-permeation chromatography (HPLC/GPC). (usgs.gov)
  • Analytical methods reported mainly include thin layer chromatography (TLC) (6), high-speed counter current chromatography (HSCCC) (7, 8), micellar electro kinetic chromatography (MEKC) (9), capillary zone electrophoresis (CZE) (10), high-performance liquid chromatography (HPLC) (11-13) and ultra-performance liquid chromatography (UPLC) (14). (deepdyve.com)
  • Gas Chromatography coupled with Mass Spectrometry is a widely used technique for the analysis and quantification of organic compounds. (uclouvain.be)
  • Vidal, J. L. M., Liébanas, F. J. A., Rodríguez, M. J. G., Frenich, A. G. and Moreno, J. L. F. (2006), Validation of a gas chromatography/triple quadrupole mass spectrometry based method for the quantification of pesticides in food commodities. (wiley.com)
  • The methods are based on pyrolysis (Py) performed in a programmed-temperature vaporization injector with subsequent identification and quantification of the components in the pyrolysate using capillary gas chromatography-mass spectrometry (GC-MS). By injecting large volumes and applying cryo-focussing at the top of the column, low detection limits could be achieved. (uva.nl)
  • In this work, the potential of atmospheric pressure chemical ionization (APCI), a softer form of ionization, combined with GC and a triple quadrupole mass analyzer was investigated, taking pyrethroids as a case study and their determination in fruit and vegetables as example application. (wur.nl)
  • The sample flows through the column and the compounds of the mixture of interest are separated thanks to their relative interaction with the stationary phase (coating of the column) and the mobile phase (carrier gas). (uclouvain.be)
  • The comparison of the mass spectra obtained with those of the database constitutes an aid to the identification of the compounds. (uclouvain.be)
  • The volatile compounds in Roselle extract and dried samples were performed using needles of solid phase microextraction (SPME) and gas chromatography/mass spectrometry (GC/MS HP-5890). (scribd.com)
  • Pyrolysis gas chromatography is useful for the identification of involatile compounds. (wikipedia.org)
  • Analysis of aromatic compounds in the New Zealand manuka honey was carried out by solid phase microextraction followed by gas chromatography-mass spectrometry. (hindawi.com)
  • A microanalytical technique combining mass spectrometry and gas chromatography for the qualitative as well as quantitative determinations of compounds. (harvard.edu)
  • In this paper, these compounds were derivatized with trifluoroacetic (TFA) anhydride and analyzed by gas chromatography/mass spectrometry using electron ionization in positive mode. (hindawi.com)
  • Gas chromatographic separation for TFA derivatives of all compounds was successfully resolved using an Equity-5 fused silica capillary column with a poly (5% diphenyl-95% dimethylsiloxane) stationary phase. (hindawi.com)
  • Gas chromatography (GC) is employed in analytical chemistry for analyzing and separating compounds that can be vaporized without decomposition. (confirmbiosciences.com)
  • Gas chromatography coupled to mass spectrometry (GC/MS) has been extensively applied for determination of volatile, nonpolar, compounds in many applied fields like food safety, environment, or toxicology. (wur.nl)
  • Gas chromatography/mass spectrometry (GC-MS) is a common analytical technique to profile the compounds that comprise lignin depolymerization products. (rsc.org)
  • The composition of detectable small organic compounds in the ethanol extract of Achillea micrantha was defined by means of gas chromatography-mass spectrometric analysis. (ijpsonline.com)
  • Compounds are identified from the mass spectrum by their unique ion fragmentation patterns. (mee-inc.com)
  • This compound identification analysis is performed by a computerized comparison of the mass spectra for the sample with spectra library for known compounds. (mee-inc.com)
  • I further explain how unknown compounds can be identified (non-target screening) using mass spectral analysis and several other approaches (e.g. retention indices). (diva-portal.org)
  • Electron ionization-mass spectrometry (EI-MS) has been used to analyze different kinds of compounds, but it is more suitable for single analyte. (deepdyve.com)
  • Nondestructive sample cleanup and comprehensive two-dimensional gas chromatography (GCXGC) high-resolution mass spectrometry (HRMS) analysis generated a massive amount of data that could be used for nontarget screening purposes. (diva-portal.org)
  • Extracted analytes were derivatized with pentafluoropropionic anhydride and pentafluoropropanol and quantified by gas chromatography-mass spectrometry (GC/MS) with electron impact ionization. (ovid.com)
  • Here, we present pyrolysis coupled to online gas chromatography and electron impact ionization mass spectrometry (py-GC/MS) as quick and reliable tool for pigment identification using both purified pigments and tattoo ink formulations. (pubmedcentralcanada.ca)
  • The identification of lipids using gas chromatography- electron impact mass spectrometry (GC-EI/MS) could provide an alternative solution. (open.ac.uk)
  • Gas chromatography-mass spectrometry (GC-MS) is a hybrid analytical technique that couples the separation capabilities of GC with the detection properties of MS to provide a higher efficiency of sample analyses. (news-medical.net)
  • The volatile components in cucumbers were studied by vacuum distill-freeze concentration, microwave-ultrasonic extraction and solid-phase microextraction (SPME) techniques combined with gas chromatography-mass spectrometry (GC-MS) analyses. (ebscohost.com)
  • The structural and chemical heterogeneity of the produced carbons are characterized by Fourier transform infrared spectrometry, X-ray photoelectron spectroscopy, Boehm titration method and N2/77 K adsorption isotherm. (environmental-expert.com)
  • Watch the next lesson: https://www.khanacademy.org/test-prep/mcat/chemical-processes/separations-purifications/v/thin-layer-chromatography?utm_source=YT&utm_medium=Desc&utm_campaign=mcat Missed the previous lesson? (wn.com)
  • Dai, Heshuang;Chen, Zhiqiong;Shang, Bing;Chen, Qinhua 2018-03-01 00:00:00 Abstract A gas chromatographic-mass spectrometric (GC-MS) method was developed for the determination of four anthraquinones found in rhubarb. (deepdyve.com)
  • Zhang WJ, Liu C, Yang RJ, Zheng TT, Zhao MM, Ma L, Yan L. Comparison of volatile profiles and bioactive components of sun-dried Pu-erh tea leaves from ancient tea plants on Bulang Mountain measured by GC-MS and HPLC. (harvard.edu)
  • Fast Gas Chromatography with Tandem Mass Spectrometry Analysis of. (ingentaconnect.com)
  • The latest developments in instrumentation, including tandem mass spectrometry (MS-MS) and time-of-flight (TOF) detectors, have opened up and broadened the scope of environmental analytical chemistry. (waterstones.com)
  • In the following study, we came up with and validated a prompt, sensitive and precise method for the simultaneous determination of 56 antimicrobial drugs (tetracyclines, sulfonamides, β-lactams, macrolides and quinolones) using the ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). This method was implemented with success to determine antibiotics in samples collected from four wastewater treatment plants and five coasts in Tunisia. (environmental-expert.com)
  • The trace analysis of alkyl alkylphosphonic acids in urine using gas chromatography-ion trap negative ion tandem mass spectrometry. (biomedsearch.com)
  • Ettre LS (2001) The predawn of paper chromatography. (springer.com)
  • GC-MS is ideal for the analysis of inorganic gases and aromatic solvents, detection of impurities and allergens in cosmetics. (news-medical.net)
  • Chemical detection systems based on chemo-resistive sensors usually include a gas chamber to control the sample air flow and to minimize turbulence. (mdpi.com)
  • Analytes are separated, and detected by one of several available detection systems, including mass spectrometry (MS). However, this mode of operation is not convenient when monitoring dynamic chemical systems - for example, reaction mixtures. (rsc.org)
  • Gas Chromatography Mass Spectrometry analysis has been used in the detection of illegal drugs and substances, as well as in forensic toxicology. (confirmbiosciences.com)
  • Due to its structurally significant mass spectral peaks, extended range of analyzable low volatility samples, enhanced molecular ions, and valuable isotope ratio information, GC-MS is a powerful tool for geochemical applications. (news-medical.net)
  • The measurement of skeletal muscle protein fractional synthetic rate using an infusion of (1-13C)leucine and measuring the isotopic abundance of the tracer in skeletal muscle protein by preparative gas chromatography (GC)/ninhydrin isotope ratio mass spectrometry (IRMS) is laborious and subject to errors owing to contamination by 12C. (nih.gov)
  • A large number (3074) of tree-ring α-cellulose samples are used to compare the stable carbon isotope ratios (δ13C) produced by high-temperature (1400°C) pyrolysis/gas chromatography (GC)/isotope ratio mass spectrometry (IRMS) with those produced by combustion GC/IRMS. (nerc.ac.uk)
  • Currently more than 100 genetic metabolic disorders can be determined in a urine test of a newborn based on Gas Chromatography Mass Spectrometry. (confirmbiosciences.com)
  • Assessment of antifungal drug therapy in autism by measurement of suspected microbial metabolites in urine with gas chromatography-mass spectrometry. (greatplainslaboratory.com)
  • The differences between Gas Chromatography and Immunoassay when performing urine drug screen testing. (booksie.com)
  • While GC can separate volatile components in a sample, MS helps fragment the components and identify them on the basis of their mass. (news-medical.net)
  • James AT, Martin AJ (1952) Gas-liquid partition chromatography: the separation and micro- estimation of volatile fatty acids from formic acid to dodecanoic acid. (springer.com)
  • Gas chromatography (GC) is frequently used in qualitative and quantitative analysis of volatile organic molecules. (rsc.org)
  • The results of the single-drop extraction in combination with gas chromatography show promising potential for the analysis of volatile aldehydes in vegetables. (ebscohost.com)
  • Real-Time Profiling of Volatile Malt Aldehydes Using Selected Ion Flow Tube Mass Spectrometry. (ebscohost.com)
  • Classical gas chromatography-mass spectrometry (GC-MS) with electron ionization (EI) is typically applied for the analysis of low-molecular-weight, apolar (and thus relatively volatile) solutes, resulting in high sensitivity and library searchable spectra. (chromatographyonline.com)
  • Gas chromatography / mass spectrometry (GC/MS) is the marriage of two analytical methods into a versatile technique for the identification of complex volatile materials. (mee-inc.com)
  • The instrument also includes a heated injection port to vaporize all volatile constituents of the sample and an oven to keep the constituents in gas form as they pass through the column. (mee-inc.com)
  • European Journal of Mass Spectrometry. (wikipedia.org)
  • Journal of Chromatography A. 1186 (1-2): 222-227. (wikipedia.org)
  • Journal of Chromatography A. 983 (1-2): 1-18. (wikipedia.org)
  • Erwin Kaal, Sjaak de Koning, Stella Brudin, Hans-Gerd Janssen Journal of Chromatography A, 1201 (2008) 169-175. (wikibooks.org)
  • European journal of mass spectrometry (Chichester, England) 12 (1): 1-13. (wikibooks.org)
  • Journal of chromatography. (wikibooks.org)
  • Manville, J.F. Journal of Chromatography 648: 433-443. (gc.ca)
  • author={Wen Hao Ding and Christopher T Chen}, journal={Journal of chromatography. (semanticscholar.org)
  • Gas chromatography-mass spectrometry ( GC-MS ) is an analytical method that combines the features of gas-chromatography and mass spectrometry to identify different substances within a test sample. (wikipedia.org)
  • Pyrolysis-gas chromatography-mass spectrometry is a method of chemical analysis in which the sample is heated to decomposition to produce smaller molecules that are separated by gas chromatography and detected using mass spectrometry. (wikipedia.org)
  • We show that in open sampling systems, training the classifiers only on high concentrations of gases produces less effective classification and that it is important to calibrate the classification method with data at low gas concentrations to achieve optimal performance. (mdpi.com)
  • A gas chromatography with mass spectrometry method was developed for the simultaneous determination of ten kinds of glycol ethers and their acetates in cosmetics. (sigmaaldrich.com)
  • The prepared samples were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) method, and scanning electron microscopy (SEM) equipped with energy dispersive spectrometry (EDS). (environmental-expert.com)
  • To study chemical classification of animals and plants for exploitation, fatty-acid compositions of 23 plant oils and 16 animal oils extracted by supercritical CO2 fluid extraction were determined by gas chromatography-mass spectrometry method(GC-MS) and these compositions were analyzed by. (ebscohost.com)
  • A programmed-temperature gas-liquid chromatographic method of analysis of amino acids as their n -butyl esters of N(O)-trifluoro-acetyl derivatives with a dual column system using OV-17 and Dexsil 300 GC as stationary phase is discussed. (springer.com)
  • Lanthionine, lysinoalanine, and S-(2-carboxyethyl)-cysteine in the hydrolyzates of chemically modified wool fibers can be quantitatively analyzed by the gas-liquid chromatographic method on Dexsil 300 GC. (springer.com)
  • Capillary gas chromatographic and gas chromatographic--mass spectrometric methods were employed for profiling total fatty acid content of human erythrocyte membranes. (nih.gov)
  • Besides, gas chromatographic-flame ionization detector and gas chromatographic-mass spectrometric (GC-MS) have also gained general acceptance for analysis of Chinese herbs, owing to high sensitivity combined with the possibility of achieving efficient separations of complex mixtures (17, 18). (deepdyve.com)
  • The insides of the GC-MS, with the column of the gas chromatograph in the oven on the right. (wikipedia.org)
  • The gas chromatograph utilizes a capillary column which depends on the column's dimensions (length, diameter, film thickness) as well as the phase properties (e.g. 5% phenyl polysiloxane). (wikipedia.org)
  • These fragments can then be separated on a gas chromatograph (GC). (wikibooks.org)
  • Simultaneous determination of glycol ethers and their acetates in cosmetics by gas chromatography with mass spectrometry. (sigmaaldrich.com)
  • Determination of Some Amino Acids by Gas Chromatography of Derivatives. (springer.com)
  • Gas-Liquid Chromatography of Trifluoroacetylated Amino Acid Methyl Esters: Determination of Their Molar Responses with the Flame Ionization Detector. (springer.com)
  • A section on how to interpret mass spectral data, an extensive correlation of ion masses and neutral losses with possible structures, and examples of mass spectra are provided to further aid structure determination. (mexmat.ru)
  • BS-EN-62321-7-2 › Determination of certain substances in electrotechnical products. (document-center.com)
  • Several gas chromatographic methods to analyze MA, AM, MDMA, MDEA, MBDB, MDA, and BDB in doping control and toxicological analysis have been reported [ 5 - 8 ]. (hindawi.com)
  • We developed non-discriminating sample preparation methods for gas chromatography-mass spectrometry (GC-MS) analysis. (diva-portal.org)
  • Fiehn 2002 ) Typical strategy: Simple sample pretreatment followed by NMR, FTIR, or direct infusion mass spectrometry (DIMS). (springer.com)
  • Gas chromatography separates the components of a mixture, and mass spectrometry characterizes each of the components individually. (springer.com)
  • It combines the features of gas-chromatography which separates substances in a mixture primarily based on the boiling point but also on the affinity of the column used for the separation. (niom.no)
  • Gas chromatography (GC) effectively separates the different constituents of the sample for subsequent analysis and identification by mass spectrometry (MS). (mee-inc.com)
  • Fatty acid composition of human erythrocyte membranes by capillary gas chromatography-mass spectrometry. (nih.gov)
  • Although it was built for portability and speed, the low thermal mass (LTM) capillary GC provides equivalent chromatographic resolution and performance to a benchtop system. (perkinelmer.com)
  • Confirmation of identities by mass spectral structure elucidation revealed saturated, mono- and polyunsaturated, and branched-chain FAMEs. (nih.gov)
  • Their structures were deduced from the mass spectral data. (hindawi.com)
  • Although a very useful tool, the analysis of lignin depolymerization products with GC-MS is limited by the quality and scope of the available mass spectral libraries and the ability to correlate changes in GC-MS chromatograms to changes in lignin structure, catalyst structure, and other reaction conditions. (rsc.org)
  • For fingerprinting studies all observed mass features, here called mass spectral tags (MSTs), are quantified in a nontargeted and (within the limits of the GC-MS technology) comprehensive approach. (nih.gov)
  • Identification of TPO blooming products after environmental exposure by Fourier-transform infrared (FTIR) & gas chromatography coupled to mass spectrometry(GC-MS)," SAE Technical Paper 2018-36-0063, 2018, https://doi.org/10.4271/2018-36-0063 . (sae.org)
  • The samples for GC/MS can be gases, liquids, or solids. (mee-inc.com)
  • Gases and liquids can be injected directly into the sample injector. (mee-inc.com)
  • When using MS as the detector, these substances may be identified by the mass spectra. (niom.no)
  • NIOM has extensive experience with the use of gas chromatography and have made our own library of substances over the years, which helps us to identify unknowns based on retention time. (niom.no)
  • Quantitative Gas-Liquid Chromatography of Amino Acids in Proteins and Biological Substances. (springer.com)
  • To achieve this, we employed pyrolysis/gas chromatography (py/gc) and pyrolysis/gas chromotography/mass spectrometry (py/gc/ms). Pyrolysis techniques have been used to examine peat, coal, coalified wood, and related substances. (usgs.gov)
  • Gas Chromatography-Mass Spectrometry" is a descriptor in the National Library of Medicine's controlled vocabulary thesaurus, MeSH (Medical Subject Headings) . (harvard.edu)
  • Analysis of phenylpiperazine-like stimulants in human hair as trimethylsilyl derivatives by gas chromatography-mass spectrometry. (sigmaaldrich.com)
  • Quantitative Gas-Liquid Chromatography and Mass Spectrometry of the N(O)-Perfluoro-butyryl-O-Isoamyl Derivatives of Amino Acids. (springer.com)
  • Combined Gas Chromatography-Mass Spectrometry of Amino Acid Derivatives. (springer.com)
  • GC/mass spectrometry (MS) using the electron ionization (EI) mode is a widely used technique in drug analysis, as it leads to a number of fragment ions providing structural information [ 11 ]. (hindawi.com)
  • The phenanthrols were silylated and analyzed by gas chromatography-positive ion chemical ionization-mass spectrometry with selected ion monitoring. (aacrjournals.org)
  • Derivatized sugars, organic acids, and amino acids show strong fragmentation in electron ionization-mass spectrometry (EI-MS) with non-characteristic fragment ions, whereas GC-APCI-MS and GC-SMB-MS offer easier feature extraction and compound identification. (chromatographyonline.com)
  • The sample is injected into the GC inlet where it is vaporized and eluted on a chromatographic column by the carrier gas, generally helium. (uclouvain.be)
  • A gas chromatography/mass spectrometry system based on the combination of an automated vapor sample inlet, a transfer line gas chromatography module, and a modified Hewlett Packard model 5971A quadrupole MS system were used. (cdc.gov)
  • For apolar high boiling solutes, such as lipids, high-temperature GC or liquid chromatography (LC) are used. (chromatographyonline.com)
  • A gas chromatography test is commonly used to separate the various components of a mixture, to test the purity of a specific substance or to help identify a particular compound. (confirmbiosciences.com)
  • Therefore, when an identifying mass spectrum appears at a characteristic retention time in a GC-MS analysis, it typically increases certainty that the analyte of interest is in the sample. (wikipedia.org)
  • For the first time, chemo-resistive gas sensors are exposed to dynamic gas mixtures generated with several concentration levels at the sources. (mdpi.com)
  • We used a support vector machine as a tool to show that chemo-resistive transduction can be utilized to reliably identify chemical components in dynamic turbulent mixtures, as long as sufficient gas concentration coverage is used. (mdpi.com)
  • Fonollosa J, Rodríguez-Luján I, Trincavelli M, Vergara A, Huerta R. Chemical Discrimination in Turbulent Gas Mixtures with MOX Sensors Validated by Gas Chromatography-Mass Spectrometry. (mdpi.com)
  • A mass spectrometry analysis may be used for both complex mixtures and pure samples. (confirmbiosciences.com)
  • Gas Liquid Chromatographic Studies on the Twenty Protein Amino Acids: A Single Column Separation. (springer.com)
  • The analytes were derivatized with N-methyl-N-(trimethylsilyl) trifluoroacetamide with 5% trimethylchlorosilane and analysed by gas chromatography-mass spectrometry in the selected ion monitoring mode. (sigmaaldrich.com)
  • Analysis of captan, folpet, and captafol in apples by dispersive liquid-liquid microextraction combined with gas chromatography. (ebscohost.com)
  • Mass spectrometry (MS) is a technique that analytically categorizes the ions based on their mass to charge ratio, and ionizes atoms, molecules, ions, molecular fragments and other chemical species. (confirmbiosciences.com)
  • The mass spectrometry analysis aids in determining the chemical's unique structure or its "fingerprint" which could be compared to an extensive library of identified chemical fingerprints. (confirmbiosciences.com)
  • Size-exclusion chromatography (SEC) and Py-GC-MS were used to measure molecular weights and average chemical compositions, respectively. (uva.nl)
  • These were analysed by GC-MS in the negative-ion chemical-ionisation mode with ammonia moderating gas. (lu.se)
  • The results suggest that the EN can complement traditional chemical and sensory approaches to the optimization of beer aging. (mbaa.com)