Gas Chromatography-Mass Spectrometry: A microanalytical technique combining mass spectrometry and gas chromatography for the qualitative as well as quantitative determinations of compounds.Mass Spectrometry: An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.Chromatography, Gas: 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.Chromatography, Liquid: Chromatographic techniques in which the mobile phase is a liquid.Chromatography, High Pressure Liquid: Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.Volatile Organic Compounds: Organic compounds that have a relatively high VAPOR PRESSURE at room temperature.Solid Phase Microextraction: 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.Metabolomics: 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.Tandem Mass Spectrometry: 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.Metabolome: The dynamic collection of metabolites which represent a cell's or organism's net metabolic response to current conditions.Perianal GlandsSpectrometry, Mass, Electrospray Ionization: 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, Volatile: 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.Volatilization: A phase transition from liquid state to gas state, which is affected by Raoult's law. It can be accomplished by fractional distillation.Ocimum basilicum: A plant species of the genus OCIMUM, family LAMIACEAE. It is a condiment with carminative properties.Chromatography, Thin Layer: 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)Androstenediols: Unsaturated androstane derivatives which are substituted with two hydroxy groups in any position in the ring system.Acetic Anhydrides: Compounds used extensively as acetylation, oxidation and dehydrating agents and in the modification of proteins and enzymes.Substance Abuse Detection: Detection of drugs that have been abused, overused, or misused, including legal and illegal drugs. Urine screening is the usual method of detection.Meconium: 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: Deuterium. The stable isotope of hydrogen. It has one neutron and one proton in the nucleus.Doping in Sports: Illegitimate use of substances for a desired effect in competitive sports. It includes humans and animals.F2-Isoprostanes: 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.Magnetic Resonance Spectroscopy: 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).Fatty Acids: 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)Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization: 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.Biotransformation: 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.Carboxylic Acids: 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.Hydroxyeicosatetraenoic Acids: 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.Gases: 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)Urinalysis: 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.Reproducibility of Results: 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.Oxidation-Reduction: 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).EstersQuality Control: 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)Steroids: 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)Methylation: 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)Molecular Structure: 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.Carbohydrate Conformation: The characteristic 3-dimensional shape of a carbohydrate.Water Pollutants, Chemical: Chemical compounds which pollute the water of rivers, streams, lakes, the sea, reservoirs, or other bodies of water.Carbohydrate Sequence: The sequence of carbohydrates within POLYSACCHARIDES; GLYCOPROTEINS; and GLYCOLIPIDS.Lipoxygenase: 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.Molecular Sequence Data: 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.Polycyclic Hydrocarbons, Aromatic: 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)Stereoisomerism: 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)Sensitivity and Specificity: 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)Chemistry: A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.Chemical Phenomena: The composition, conformation, and properties of atoms and molecules, and their reaction and interaction processes.Arachidonic AcidsArachidonic Acid: 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.Hydrolysis: The process of cleaving a chemical compound by the addition of a molecule of water.Proteomics: The systematic study of the complete complement of proteins (PROTEOME) of organisms.Dinoprost: 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.Cytochrome P-450 Enzyme System: 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, Unsaturated: FATTY ACIDS in which the carbon chain contains one or more double or triple carbon-carbon bonds.Biological Markers: 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.Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Hexanes: Six-carbon saturated hydrocarbon group of the methane series. Include isomers and derivatives. Various polyneuropathies are caused by hexane poisoning.Chromatography, Affinity: 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)Time Factors: Elements of limited time intervals, contributing to particular results or situations.Cattle: 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.Chromatography, Ion Exchange: 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.Kinetics: The rate dynamics in chemical or physical systems.Eucommiaceae: 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).Calibration: 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.Amino Acid Sequence: 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.Lipid Metabolism: Physiological processes in biosynthesis (anabolism) and degradation (catabolism) of LIPIDS.Isotope Labeling: 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.Pentanes: Five-carbon saturated hydrocarbon group of the methane series. Include isomers and derivatives.Chromatography: 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.8,11,14-Eicosatrienoic Acid: 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.Reference Standards: 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.Proteome: The protein complement of an organism coded for by its genome.Limit of Detection: Concentration or quantity that is derived from the smallest measure that can be detected with reasonable certainty for a given analytical procedure.Chromatography, Gel: Chromatography on non-ionic gels without regard to the mechanism of solute discrimination.Rhodiola: 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.Breath Tests: Any tests done on exhaled air.Reference Values: 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.Water Pollutants: 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.Flame Ionization: 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.Sugar AcidsCarbon Radioisotopes: Unstable isotopes of carbon that decay or disintegrate emitting radiation. C atoms with atomic weights 10, 11, and 14-16 are radioactive carbon isotopes.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.Chromatography, Reverse-Phase: 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.Methanol: 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.Glucose: 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.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Environmental Monitoring: 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.Cholesterol: The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.Oligosaccharides: 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.Sugar Alcohols: 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)Oxidative Stress: 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).Acetates: Derivatives of ACETIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the carboxymethane structure.Microsomes, Liver: Closed vesicles of fragmented endoplasmic reticulum created when liver cells or tissue are disrupted by homogenization. They may be smooth or rough.Sulfur Compounds: Inorganic or organic compounds that contain sulfur as an integral part of the molecule.Peptides: 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.Fungicides, Industrial: Chemicals that kill or inhibit the growth of fungi in agricultural applications, on wood, plastics, or other materials, in swimming pools, etc.Terphenyl Compounds: 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.Solid Phase Extraction: 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.Amino Acids: 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, Gel, Two-Dimensional: 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.Indicator Dilution Techniques: 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)HydrocarbonsSpectrometry, Mass, Secondary Ion: 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.Isotopes: Atomic species differing in mass number but having the same atomic number. (Grant & Hackh's Chemical Dictionary, 5th ed)Molecular Weight: The sum of the weight of all the atoms in a molecule.Pesticide Residues: Pesticides or their breakdown products remaining in the environment following their normal use or accidental contamination.Bile: 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.Spectrometry, Mass, Fast Atom Bombardment: 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.Spectrophotometry, Ultraviolet: 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, Polyacrylamide Gel: Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.Plant Extracts: 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.Glucuronides: 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.PolysaccharidesIons: 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.GlyoxalPhenols: Benzene derivatives that include one or more hydroxyl groups attached to the ring structure.Hydroxylation: Placing of a hydroxyl group on a compound in a position where one did not exist before. (Stedman, 26th ed)Peptide Fragments: Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.Mycolic AcidsDisaccharides: Oligosaccharides containing two monosaccharide units linked by a glycosidic bond.Pharmaceutical Preparations: 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.Rats, Sprague-Dawley: 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.Hydrogen-Ion Concentration: 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)Indicators and Reagents: 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)Brain Chemistry: 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.Escherichia coli: 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.Lipids: 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)Substrate Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.Environmental Pollutants: 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.Peptide Mapping: 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.Amines: A group of compounds derived from ammonia by substituting organic radicals for the hydrogens. (From Grant & Hackh's Chemical Dictionary, 5th ed)Temperature: 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.Recombinant Proteins: Proteins prepared by recombinant DNA technology.Microchemistry: 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.Case-Control Studies: 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.Brain: 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.Species Specificity: 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.Amides: 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)Models, Chemical: Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.Phospholipids: 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.Chemical Fractionation: 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)Mixed Function Oxygenases: 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.Endocannabinoids: 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.Bacterial Proteins: Proteins found in any species of bacterium.Administration, Oral: The giving of drugs, chemicals, or other substances by mouth.Area Under Curve: 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)Tissue Distribution: 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.Forensic Medicine: The application of medical knowledge to questions of law.Swine: 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).Cytochrome P-450 CYP3A: 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.Software: Sequential operating programs and data which instruct the functioning of a digital computer.Deuterium Exchange Measurement: A research technique to measure solvent exposed regions of molecules that is used to provide insight about PROTEIN CONFORMATION.Proteins: 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.Aryl Hydrocarbon Hydroxylases: 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.Polyunsaturated Alkamides: 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 ...
... ,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
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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, ...
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...
Close The Infona portal uses cookies, i.e. strings of text saved by a browser on the users device. The portal can access those files and use them to remember the users data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser. ...
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 ...
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 ...
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 ...
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) ...
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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 ...
Sigma-Aldrich offers abstracts and full-text articles by [Jing Nie, Shui Miao, Steven J Lehotay, Wen-Ting Li, Heng Zhou, Xiu-Hong Mao, Ji-Wei Lu, Lan Lan, Shen Ji].
Methods of Analysis Determination of Pyrethroid Insecticides in Water and Sediment Using Gas Chromatography/Mass Spectrometry Techniques and Methods 5 C2 U.S. Department of the Interior U.S. Geological
A method for quantifying in vivo ascorbate concentration in body fluids uses gas chromatography/mass spectrometry (GC/MS). Further provided is a method for measuring redox potentials of body fluid by determining the ratio of in vivo concentration of ascorbate to one or more of its metabolites.
A sensitive method has been developed for the trace analysis of PAHs and their oxidation products (i.e., nitro-, oxy-, and hydroxy-PAHs) in air particulate matter (PM). Following PM extraction, PAHs, nitro-, oxy-, and hydroxy-PAHs were fractionated using solid phase extraction (SPE) based on their polarities. Gas chromatography-mass spectrometry (GC-MS) conditions were optimized, addressing inject ...
Gas chromatography-mass spectrometry (GC-MS) is a powerful analytical tool for detection, identification, and quantification of many volatile organic compounds. However, many colleges and universities have not fully incorporated this technique into undergraduate teaching laboratories despite its wide application and ease of use in organic chemistry. In this article, a set of experiments are provided to educators for the purposeful integration of the GC-MS technique into undergraduate organic chemistry laboratories. The laboratories provide students experimental opportunities to use GC-MS as the main analytical tool for (a) identification and quantification of major and minor product(s) formed in three common organic synthesis reactions and (b) extraction, separation, and identification of multiple natural products found in fruits and vegetables.
One of the uses of Gas Chromatography-Mass Spectrometry (GC-MS) is in the detection of pesticide residues in fruit and vegetables. In a high throughput laboratory there is the potential for sample swaps or mislabelling, as once a sample has been pre-processed to be injected into the GC-MS analyser, it is no longer distinguishable by eye. Possible consequences of such mistakes can be the destruction of large amounts of actually safe produce or pesticide-contaminated produce reaching the consumer. For the purposes of food safety and traceability, it can also be extremely valuable to know the source (country of origin) of a food product. This can help uncover fraudulent attempts of trying to sell food originating from countries deemed unsafe. In this study, we use the workflow environment ADAMS to examine whether we can determine the fruit/vegetable, and the country of origin of a sample from a GC-MS chromatogram. A workflow is used to generate data sets using different data pre-processing methods, ...
Chokwe, TB et al. Improved derivatization protocol for simultaneous determination of alkylphenol ethoxylates and brominated flame retardants followed by gas chromatography-mass spectrometry analyses. Water SA, 2015, vol.41, no.2, p.189-193. ISSN 1816- ...
By Choi, Hyong Woo Lee, Byung Gil; Kim, Nak Hyun; Park, Yong; Lim, Chae Woo; Song, Hyun Kyu; Hwang, Byung Kook Plants elaborate a vast array of enzymes that synthesize defensive secondary metabolites in response to pathogen attack. Here, we isolated the pathogen-responsive CaMNR1 [menthone: (1)- (3S)-neomenthol reductase] gene, a member of the short-chain dehydrogenase/reductase (SDR) superfamily, from pepper (Capsicum annuum) plants. Gas chromatography-mass spectrometry analysis revealed that purified CaMNR1 and its ortholog AtSDR1 from Arabidopsis (Arabidopsis thaliana) catalyze a menthone reduction with reduced nicotinamide adenine dinucleotide phosphate as a cofactor to produce neomenthol with antimicrobial activity. CaMNR1 and AtSDR1 also possess a significant catalytic activity for neomenthol oxidation. We examined the cellular function of the CaMNR1 gene by virus-induced gene silencing and ectopic overexpression in pepper and Arabidopsis plants, respectively. CaMNR1-silenced pepper plants ...
A method for the analysis of testosterone, androstenedione, 5β-dihydrotestosterone, 11-ketotestosterone, estrone, 17β-estradiol, 17α-hydroxyprogesterone, 17α,20β-dihydroxy-4-pregnen-3-one, 5β-pregnane-3α,17α,20α-triol, 5β-androstane-3α,17β-diol, 5β-androstane-3β,17β-diol, 5β-pregnane-3α,17α,20β-triol, 5β-androstane-3α,11β-diol-17-one, 5β-pregnane-3α,17α-diol-20-one, 17α,20β,21-trihydroxy-pregn-4-en-3-one and 11-deoxycortisol in water was developed using gas chromatography-mass spectrometry with selected ion monitoring.. Fish sex steroids were extracted from holding water using C18 SPE cartridges, and eluted using methanol. Free and glucuronide conjugate levels of steroids were determined, glucuronide conjugates by hydrolysis using β-glucuronidase prior to. derivatisation and free steroids by direct derivatisation. The method thus developed was applied to twelve goldfish holding water samples.. Androstenedione was found to be excreted in considerably higher quantities ...
Laser-micropyrolysis gas chromatography-mass spectrometry (La-Py-GC-MS) allows the analysis of small targeted areas of organic material. In this proof of concept study a novel application of the technique is demonstrated. Three types of organic matter preserved in speleothems were analysed: dissolved organic matter within the calcite crystal matrix; detrital organic inclusions; and lithified guano derived from birds and bats. The results indicate that there is significant heterogeneity within each sample type, with guano samples having the highest variability. However, there are also distinctive La-Py-GC-MS products that allow separation of the sample types geochemically. These include the chain length distribution within the longer chain n-alkanes (,C20), with the guano sample having a dominance of chain lengths below C27, whilst the other two sample types are dominated by n-alkanes of C27 and above. The detrital inclusion sample has a higher relative abundance of pyrrole and methylpyrroles. A ...
Take the Torion T-9 portable GC/MS to your samples, wherever they are. PerkinElmers Torion® T-9 portable gas chromatograph/mass spectrometer (GC/MS) brings new meaning to portability. At a total weight of only 32 pounds, this one of-a-kind GC/MS is also fast, reliable and easy to use. Torion technology integrates a high speed low thermal mass (LTM) capillary gas chromatograph (GC) with a miniaturized toroidal iontrap mass spectrometer to provide a fast, reliable and easy-to-operate GC/MS. The portable Torion T-9 GC/MS is designed to carry in the field and ideal for rapid screening of chemicals such as environmental volatiles and semivolatiles (VOCs/SVOCs), explosives, chemical threat, and hazardous substances.
Robert J. H. Woestenborghs, Philip M. M. B. L. Timmerman, Marie-Louise J.E. Cornelissen, Frank A. M. B. S. Van Rompaey, Elisabeth Gepts, Frederic Camu, Joseph J. P. Heykants, Donald R. Stanski; Assay Methods for Sufentanil in Plasma: Radioimmunoassay Versus Gas Chromatography-Mass Spectrometry. Anesthesiology 1994;80(3):666-670. Download citation file:. ...
... (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 ...
"Analysis of Amphetamine-Derived Designer Drugs by Gas Chromatography with Mass Spectrometry". Journal of Analytical Toxicology ...
"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. ...
ISBN 978-1-60774-172-5. Linskens, Hans-Ferdinand; Jackson, John F. (2012-12-06). Gas Chromatography/Mass Spectrometry. Springer ...
"Determination of MDPBP in postmortem blood samples by gas chromatography coupled with mass spectrometry". Monatshefte für ...
"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/ ...
Gas Chromatography, Infrared Spectrometry or Mass Spectrometry is used in combination with the color test to identify the type ... Lehrer, M. (1998). "The role of gas chromatography/mass spectrometry. Instrumental techniques in forensic urine drug testing". ... and identifying human remains of victims from mass disasters or missing person cases. [13] It is also used to link suspects or ...
Using gas chromatography and mass spectrometry. (E,E) 9,12-octadecadienoic acid, methyl ester, 9-Octadecenoic acid(Z)-,methyl ...
"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.[123] The brands Kübler and Lucid and their lawyers ... Determination of a/β Thujone and Related Terpenes in Absinthe using Solid Phase Extraction and Gas Chromatography. Retrieved 5 ... β-Thujone and Related Terpenes in Absinthe using Solid Phase Extraction and Gas Chromatography" (PDF). Deutsche Lebensmittel- ...
... of indigoid compounds present in archaeological Maya blue by pyrolysis-silylation-gas chromatography-mass spectrometry. Journal ...
... and determination of benzodiazepines in whole blood using solid-phase extraction and gas chromatography/mass spectrometry". ... "Quantification of chlordesmethyldiazepam by liquid chromatography-tandem mass spectrometry: application to a cloxazolam ...
Gas chromatography-mass spectrometry for atmospheric analysis (MGAP). Developed by Russia. Power Russia is evaluating the ... The science payload mass is about 45 kg and consists of: The lander radio-science experiment (LaRa) will study the internal ...
"Plasma hydroxyurea determined by gas chromatography-mass spectrometry". Journal of Chromatography B. 877 (4): 446-450. doi: ...
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 ... Bruker develops and delivers a wide variety of professional and scientific analysis devices including: Mass spectrometers X-ray ...
However this technique is little used compared to GC-MS (gas chromatography-mass spectrometry) which is more sensitive. The GC- ... TG-IR (thermogravimetric analysis-infrared spectrometry)[edit]. Measuring the gas evolved as a material is heated allows ... FTIR as detector in chromatography[edit]. The speed of FTIR allows spectra to be obtained from compounds as they are separated ... Griffiths, P.; de Hasseth, J. A. (18 May 2007). Fourier Transform Infrared Spectrometry (2nd ed.). Wiley-Blackwell. ISBN 978-0- ...
Quantification of LSD and N-demethyl-LSD in urine by gas chromatography/resonance electron capture ionization mass spectrometry ... Looking to replicate the effects of nerve gas created by the Germans during World War II without the toxicity, LSD was sought ... By 1962, the Harvard faculty's disapproval with Leary's experiments reached critical mass. Leary was informed that the CIA was ... further raising interest in LSD in the mass media.[27] Following Wasson's report, Timothy Leary visited Mexico to experience ...
Confirmation was made via gas chromatography-mass spectrometry analysis. Industrially, BHT is prepared by the reaction of p- ...
They used gas chromatography and gas chromatography/mass spectrometry methods. It was found that the flowers of Iris kerneriana ...
G. F. Spencer, W. H. Tallent (1973). Sperm whale oil analysis by gas chromatography and mass spectrometry. Journal of the ... 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 ...
HRGC-MS, or High Resolution Gas Chromatography Mass Spectrometry was the first screening method for 29 dioxin and DLC congeners ... For the treatment of gases and pollutants, sugarcane industries often use wet gas scrubbers, such as the Venturi type. In ... European Union limits for concentration of dioxin-like compounds in the discharged flue gas is 0.1 ng/Nm³ TEQ.[55] ... an incineration process oxidizes all carbon to CO2 and converts all chlorine to HCl or inorganic chlorides prior to the gases ...
Goldberger BA, Cone EJ (July 1994). "Confirmatory tests for drugs in the workplace by gas chromatography-mass spectrometry". J ... Kim Y, Teylan MA, Baron M, Sands A, Nairn AC, Greengard P (February 2009). "Methylphenidate-induced dendritic spine formation ... Sudbury, Mass.: Jones and Bartlett Publishers. p. 41. ISBN 978-0-7637-4462-5. .. ... Nelson LS, Lewin NA, Howland MA, Hoffman RS, Goldfrank LR, Flomenbaum NE (2011). Goldfrank's toxicologic emergencies (9th ed ...
"A pyrolysis gas chromatography mass spectrometry study of the actinomyceteStreptomyces longisporoflavus". Biological Mass ... Boston, MA: Springer US. ISBN 1-4757-2085-8. Hopwood, edited by David A. (2009). Complex enzymes in microbial natural product ... Spectrometry. 2 (5): 261-265. doi:10.1002/bms.1200020504. Doddrell, David M.; Laue, Ernest D.; Leeper, Finian J.; Staunton, ...
Saleh, Mahmoud Abbas (1983). "Capillary gas chromatography-electron impact chemical ionization mass spectrometry of toxaphene ... using gas-chromatography-electron capture negative ion mass spectrometry (GC-ECNIMS)". Chemosphere. 39 (5): 849-871. doi: ... Toxaphene is a mixture of over 670 different chemicals and is produced by reacting chlorine gas with camphene. It can be most ...
2005). "Gas chromatography/mass spectrometry assay for arginine: glycine-amidinotransferase deficiency". Anal. Biochem. 343 (2 ... Gross MD, Eggen MA, Simon AM, Van Pilsum JF (1987). "The purification and characterization of human kidney L-arginine:glycine ...
... lateriflora by liquid chromatography with ultraviolet photodiode array and electrospray ionization tandem mass spectrometry". ... Liu X, Hong SI, Park SJ, Dela Peña JB, Che H, Yoon SY, Kim DH, Kim JM, Cai M, Risbrough V, Geyer MA, Shin CY, Cheong JH, Park H ...
Here, a gas chromatography/time-of-flight mass spectrometry (GC/TOFMS) method was developed and validated for the global ... Global gas chromatography/time-of-flight mass spectrometry (GC/TOFMS)-based metabonomic profiling of lyophilized human feces. ... Gas chromatography mass spectrometry (GC/MS)-based fecal metabonomics represents a powerful systems biology approach for ... Global gas chromatography/time-of-flight mass spectrometry (GC/TOFMS)-based metabonomic profiling of lyophilized human feces. ...
Keywords:dimethylpolysiloxanes chemical warfare agents gas chromatography mass spectrometry environmental monitoring ... a resistively heated Low Thermal Mass Gas Chromatograph column and an Entech 7100 Preconcentrator. Larger extraction ...
The level of gene expression was monitored by semi quantitative RT-PCR andphenylpropanoid compounds were identified by gas ... chromatography/mass spectrometry (GC/MS). PALactivity was assayed using spectrophotometer. The results indicated that the level ... phenylpropanoid compounds were identified by gas chromatography/mass spectrometry (GC/MS). PAL. activity was assayed using ...
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 ...
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 (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 ...
... 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 ...
tags: gas chromatography-mass spectrometry x cell & molecular biology x The Scientist. » gas chromatography-mass spectrometry ...
tags: gas chromatography-mass spectrometry x neuroscience x The Scientist. » gas chromatography-mass spectrometry and ...
"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 ...
... 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 ...
Their structures were deduced from the mass spectral data. Seven other compounds; 2,3-dimethoxynaphthalene, 4-(,i,x,/i,- ... Analysis of aromatic compounds in the New Zealand manuka honey was carried out by solid phase microextraction followed by gas ... chromatography-mass spectrometry. A total of 38 compounds were detected. Seven of them such as; 1,4-bis(,i,x,/i,-methoxyphenyl ... Identification of New Aromatic Compounds in the New Zealand Manuka Honey by Gas Chromatography-Mass Spectrometry. ...
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, ...
Volatile Organic Compounds by Vacuum Distillation in Combination with Gas Chromatography/Mass Spectrometry (VD/GC/MS). The ... Volatile Organic Compounds by Vacuum Distillation in Combination with Gas Chromatography/Mass Spectrometry (VD/GC/MS) (PDF)(99 ...
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 ...
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 ...
... 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 ...
... Anal Chim Acta. ... and were subjected to analysis by gas chromatography mass spectrometry (GC/MS). The procedure was validated in boar and horse ...
  • 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)
  • 1.2 The test method incorporates a performance-based approach, which validates each GCMS analysis by placing boundaries on the instrument response to gaseous internal standards and their specific mass spectral relative abundance. (astm.org)
  • 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)
  • 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)
  • In order to develop a better understanding of their metabolism and health we documented the urine organic acids of 41 apparently healthy captive cheetahs, in an untargeted metabolomic study, using gas chromatography-mass spectrometry. (up.ac.za)
  • 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)
  • 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)
  • 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)
  • 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)
  • 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)