Chromatography, High Pressure Liquid: Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.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)Chromatography, Liquid: Chromatographic techniques in which the mobile phase is a liquid.Chromatography, Gel: Chromatography on non-ionic gels without regard to the mechanism of solute discrimination.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.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.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, 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)Ionic Liquids: Salts that melt below 100 C. Their low VOLATILIZATION can be an advantage over volatile organic solvents.Liquid Crystals: Materials in intermediate state between solid and liquid.Molecular Weight: The sum of the weight of all the atoms in a molecule.Mass Spectrometry: An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.Chromatography, DEAE-Cellulose: A type of ion exchange chromatography using diethylaminoethyl cellulose (DEAE-CELLULOSE) as a positively charged resin. (From 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.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.Gas Chromatography-Mass Spectrometry: A microanalytical technique combining mass spectrometry and gas chromatography for the qualitative as well as quantitative determinations of compounds.Chromatography, Agarose: A method of gel filtration chromatography using agarose, the non-ionic component of agar, for the separation of compounds with molecular weights up to several million.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.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.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.Kinetics: The rate dynamics in chemical or physical systems.Spectrometry, 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.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.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)Chromatography, Paper: An analytical technique for resolution of a chemical mixture into its component compounds. Compounds are separated on an adsorbent paper (stationary phase) by their varied degree of solubility/mobility in the eluting solvent (mobile phase).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)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.Substrate Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.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.SepharoseDrug Stability: The chemical and physical integrity of a pharmaceutical product.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)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.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.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.Carbohydrates: The largest class of organic compounds, including STARCH; GLYCOGEN; CELLULOSE; POLYSACCHARIDES; and simple MONOSACCHARIDES. Carbohydrates are composed of carbon, hydrogen, and oxygen in a ratio of Cn(H2O)n.Isoelectric Focusing: Electrophoresis in which a pH gradient is established in a gel medium and proteins migrate until they reach the site (or focus) at which the pH is equal to their isoelectric point.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).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.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)Carbohydrate Sequence: The sequence of carbohydrates within POLYSACCHARIDES; GLYCOPROTEINS; and GLYCOLIPIDS.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.Peptide Fragments: Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.Methods: A series of steps taken in order to conduct research.Chromatography, Micellar Electrokinetic Capillary: A hybrid separation technique combining both chromatographic and electrophoretic separation principles. While the method was invented to separate neutral species, it can also be applied to charged molecules such as small peptides.Countercurrent Distribution: A method of separation of two or more substances by repeated distribution between two immiscible liquid phases that move past each other in opposite directions. It is a form of liquid-liquid chromatography. (Stedman, 25th ed)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.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.Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Hydrolysis: The process of cleaving a chemical compound by the addition of a molecule of water.Trypsin: A serine endopeptidase that is formed from TRYPSINOGEN in the pancreas. It is converted into its active form by ENTEROPEPTIDASE in the small intestine. It catalyzes hydrolysis of the carboxyl group of either arginine or lysine. EC 3.4.21.4.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.Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.Liquid Ventilation: Artificial respiration (RESPIRATION, ARTIFICIAL) using an oxygenated fluid.Solubility: The ability of a substance to be dissolved, i.e. to form a solution with another substance. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Isoelectric Point: The pH in solutions of proteins and related compounds at which the dipolar ions are at a maximum.Acetonitriles: Compounds in which a methyl group is attached to the cyano moiety.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.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.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.Recombinant Proteins: Proteins prepared by recombinant DNA technology.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)Protein Binding: The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.Solvents: Liquids that dissolve other substances (solutes), generally solids, without any change in chemical composition, as, water containing sugar. (Grant & Hackh's Chemical Dictionary, 5th ed)Macromolecular Substances: Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.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)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.Radioimmunoassay: Classic quantitative assay for detection of antigen-antibody reactions using a radioactively labeled substance (radioligand) either directly or indirectly to measure the binding of the unlabeled substance to a specific antibody or other receptor system. Non-immunogenic substances (e.g., haptens) can be measured if coupled to larger carrier proteins (e.g., bovine gamma-globulin or human serum albumin) capable of inducing antibody formation.Biological Assay: A method of measuring the effects of a biologically active substance using an intermediate in vivo or in vitro tissue or cell model under controlled conditions. It includes virulence studies in animal fetuses in utero, mouse convulsion bioassay of insulin, quantitation of tumor-initiator systems in mouse skin, calculation of potentiating effects of a hormonal factor in an isolated strip of contracting stomach muscle, etc.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.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Hydroxyapatites: A group of compounds with the general formula M10(PO4)6(OH)2, where M is barium, strontium, or calcium. The compounds are the principal mineral in phosphorite deposits, biological tissue, human bones, and teeth. They are also used as an anticaking agent and polymer catalysts. (Grant & Hackh's Chemical Dictionary, 5th ed)PolysaccharidesImmunodiffusion: Technique involving the diffusion of antigen or antibody through a semisolid medium, usually agar or agarose gel, with the result being a precipitin reaction.Glycoproteins: Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins.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.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)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.Culture Media: Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.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).Chemistry Techniques, Analytical: Methodologies used for the isolation, identification, detection, and quantitation of chemical substances.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Carbohydrate Conformation: The characteristic 3-dimensional shape of a carbohydrate.Cloning, Molecular: The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.Isomerism: The phenomenon whereby certain chemical compounds have structures that are different although the compounds possess the same elemental composition. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Chemical Precipitation: The formation of a solid in a solution as a result of a chemical reaction or the aggregation of soluble substances into complexes large enough to fall out of solution.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.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.Hot Temperature: Presence of warmth or heat or a temperature notably higher than an accustomed norm.Anion Exchange Resins: High-molecular-weight insoluble polymers that contain functional cationic groups capable of undergoing exchange reactions with anions.Proteomics: The systematic study of the complete complement of proteins (PROTEOME) of organisms.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.Bacterial Proteins: Proteins found in any species of bacterium.Physicochemical Phenomena: The physical phenomena describing the structure and properties of atoms and molecules, and their reaction and interaction processes.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).Chemistry, Physical: The study of CHEMICAL PHENOMENA and processes in terms of the underlying PHYSICAL PHENOMENA and processes.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Rats, Inbred Strains: Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.Isoenzymes: Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.Ammonium Sulfate: Sulfuric acid diammonium salt. It is used in CHEMICAL FRACTIONATION of proteins.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.Glycopeptides: Proteins which contain carbohydrate groups attached covalently to the polypeptide chain. The protein moiety is the predominant group with the carbohydrate making up only a small percentage of the total weight.Glycoside HydrolasesLectins: Proteins that share the common characteristic of binding to carbohydrates. Some ANTIBODIES and carbohydrate-metabolizing proteins (ENZYMES) also bind to carbohydrates, however they are not considered lectins. PLANT LECTINS are carbohydrate-binding proteins that have been primarily identified by their hemagglutinating activity (HEMAGGLUTININS). However, a variety of lectins occur in animal species where they serve diverse array of functions through specific carbohydrate recognition.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.Water: A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)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.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.Microsomes, Liver: Closed vesicles of fragmented endoplasmic reticulum created when liver cells or tissue are disrupted by homogenization. They may be smooth or rough.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.GlucosidesSequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.Centrifugation, Density Gradient: Separation of particles according to density by employing a gradient of varying densities. At equilibrium each particle settles in the gradient at a point equal to its density. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Chromatography, Supercritical Fluid: A CHROMATOGRAPHY method using supercritical fluid, usually carbon dioxide under very high pressure (around 73 atmospheres or 1070 psi at room temperature) as the mobile phase. Other solvents are sometimes added as modifiers. This is used both for analytical (SFC) and extraction (SFE) purposes.Electrochemistry: The study of chemical changes resulting from electrical action and electrical activity resulting from chemical changes.Spectrophotometry: The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.EstersGlycolipids: Any compound containing one or more monosaccharide residues bound by a glycosidic linkage to a hydrophobic moiety such as an acylglycerol (see GLYCERIDES), a sphingoid, a ceramide (CERAMIDES) (N-acylsphingoid) or a prenyl phosphate. (From IUPAC's webpage)Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Spectrometry, Fluorescence: Measurement of the intensity and quality of fluorescence.Blood Proteins: Proteins that are present in blood serum, including SERUM ALBUMIN; BLOOD COAGULATION FACTORS; and many other types of proteins.Glycosides: Any compound that contains a constituent sugar, in which the hydroxyl group attached to the first carbon is substituted by an alcoholic, phenolic, or other group. They are named specifically for the sugar contained, such as glucoside (glucose), pentoside (pentose), fructoside (fructose), etc. Upon hydrolysis, a sugar and nonsugar component (aglycone) are formed. (From Dorland, 28th ed; From Miall's Dictionary of Chemistry, 5th ed)Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.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.Cyanogen Bromide: Cyanogen bromide (CNBr). A compound used in molecular biology to digest some proteins and as a coupling reagent for phosphoroamidate or pyrophosphate internucleotide bonds in DNA duplexes.Glycosylation: The chemical or biochemical addition of carbohydrate or glycosyl groups to other chemicals, especially peptides or proteins. Glycosyl transferases are used in this biochemical reaction.TritiumDNA: A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).Fermentation: Anaerobic degradation of GLUCOSE or other organic nutrients to gain energy in the form of ATP. End products vary depending on organisms, substrates, and enzymatic pathways. Common fermentation products include ETHANOL and LACTIC ACID.Disaccharides: Oligosaccharides containing two monosaccharide units linked by a glycosidic bond.Ultracentrifugation: Centrifugation with a centrifuge that develops centrifugal fields of more than 100,000 times gravity. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Detergents: Purifying or cleansing agents, usually salts of long-chain aliphatic bases or acids, that exert cleansing (oil-dissolving) and antimicrobial effects through a surface action that depends on possessing both hydrophilic and hydrophobic properties.Trifluoroacetic Acid: A very strong halogenated derivative of acetic acid. It is used in acid catalyzed reactions, especially those where an ester is cleaved in peptide synthesis.Electrophoresis: An electrochemical process in which macromolecules or colloidal particles with a net electric charge migrate in a solution under the influence of an electric current.Carbon 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.Enzyme Stability: The extent to which an enzyme retains its structural conformation or its activity when subjected to storage, isolation, and purification or various other physical or chemical manipulations, including proteolytic enzymes and heat.Quality 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)Drug Contamination: The presence of organisms, or any foreign material that makes a drug preparation impure.Proteome: The protein complement of an organism coded for by its genome.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Monosaccharides: Simple sugars, carbohydrates which cannot be decomposed by hydrolysis. They are colorless crystalline substances with a sweet taste and have the same general formula CnH2nOn. (From Dorland, 28th ed)Solutions: The homogeneous mixtures formed by the mixing of a solid, liquid, or gaseous substance (solute) with a liquid (the solvent), from which the dissolved substances can be recovered by physical processes. (From Grant & Hackh's Chemical Dictionary, 5th ed)Sulfates: Inorganic salts of sulfuric acid.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.Ultrafiltration: The separation of particles from a suspension by passage through a filter with very fine pores. In ultrafiltration the separation is accomplished by convective transport; in DIALYSIS separation relies instead upon differential diffusion. Ultrafiltration occurs naturally and is a laboratory procedure. Artificial ultrafiltration of the blood is referred to as HEMOFILTRATION or HEMODIAFILTRATION (if combined with HEMODIALYSIS).Endopeptidases: A subclass of PEPTIDE HYDROLASES that catalyze the internal cleavage of PEPTIDES or PROTEINS.Antibodies, Monoclonal: Antibodies produced by a single clone of cells.Erythrocytes: Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.Cytosol: Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.Phenols: Benzene derivatives that include one or more hydroxyl groups attached to the ring structure.Adsorption: The adhesion of gases, liquids, or dissolved solids onto a surface. It includes adsorptive phenomena of bacteria and viruses onto surfaces as well. ABSORPTION into the substance may follow but not necessarily.Pesticide Residues: Pesticides or their breakdown products remaining in the environment following their normal use or accidental contamination.Half-Life: The time it takes for a substance (drug, radioactive nuclide, or other) to lose half of its pharmacologic, physiologic, or radiologic activity.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.Body Fluids: Liquid components of living organisms.Protein Conformation: The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).Food Analysis: Measurement and evaluation of the components of substances to be taken as FOOD.Blotting, Western: Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.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)Durapatite: The mineral component of bones and teeth; it has been used therapeutically as a prosthetic aid and in the prevention and treatment of osteoporosis.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.Immunoassay: A technique using antibodies for identifying or quantifying a substance. Usually the substance being studied serves as antigen both in antibody production and in measurement of antibody by the test substance.Silicon Dioxide: Transparent, tasteless crystals found in nature as agate, amethyst, chalcedony, cristobalite, flint, sand, QUARTZ, and tridymite. The compound is insoluble in water or acids except hydrofluoric acid.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)Liquid-Liquid Extraction: The removal of a soluble component from a liquid mixture by contact with a second liquid, immiscible with the carrier liquid, in which the component is preferentially soluble. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Chymotrypsin: A serine endopeptidase secreted by the pancreas as its zymogen, CHYMOTRYPSINOGEN and carried in the pancreatic juice to the duodenum where it is activated by TRYPSIN. It selectively cleaves aromatic amino acids on the carboxyl side.Volatilization: A phase transition from liquid state to gas state, which is affected by Raoult's law. It can be accomplished by fractional distillation.Immunoelectrophoresis: A technique that combines protein electrophoresis and double immunodiffusion. In this procedure proteins are first separated by gel electrophoresis (usually agarose), then made visible by immunodiffusion of specific antibodies. A distinct elliptical precipitin arc results for each protein detectable by the antisera.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.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.Streptomyces: A genus of bacteria that form a nonfragmented aerial mycelium. Many species have been identified with some being pathogenic. This genus is responsible for producing a majority of the ANTI-BACTERIAL AGENTS of practical value.Structure-Activity Relationship: The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.Plants: Multicellular, eukaryotic life forms of kingdom Plantae (sensu lato), comprising the VIRIDIPLANTAE; RHODOPHYTA; and GLAUCOPHYTA; all of which acquired chloroplasts by direct endosymbiosis of CYANOBACTERIA. They are characterized by a mainly photosynthetic mode of nutrition; essentially unlimited growth at localized regions of cell divisions (MERISTEMS); cellulose within cells providing rigidity; the absence of organs of locomotion; absence of nervous and sensory systems; and an alternation of haploid and diploid generations.Chickens: Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.Binding, Competitive: The interaction of two or more substrates or ligands with the same binding site. The displacement of one by the other is used in quantitative and selective affinity measurements.Administration, Oral: The giving of drugs, chemicals, or other substances by mouth.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.Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.Glucuronates: Derivatives of GLUCURONIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that include the 6-carboxy glucose structure.Circular Dichroism: A change from planar to elliptic polarization when an initially plane-polarized light wave traverses an optically active medium. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Peptide Hydrolases: Hydrolases that specifically cleave the peptide bonds found in PROTEINS and PEPTIDES. Examples of sub-subclasses for this group include EXOPEPTIDASES and ENDOPEPTIDASES.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Mannose: A hexose or fermentable monosaccharide and isomer of glucose from manna, the ash Fraxinus ornus and related plants. (From Grant & Hackh's Chemical Dictionary, 5th ed & Random House Unabridged Dictionary, 2d ed)Hexanes: Six-carbon saturated hydrocarbon group of the methane series. Include isomers and derivatives. Various polyneuropathies are caused by hexane poisoning.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.Polymers: Compounds formed by the joining of smaller, usually repeating, units linked by covalent bonds. These compounds often form large macromolecules (e.g., BIOPOLYMERS; PLASTICS).Galactose: An aldohexose that occurs naturally in the D-form in lactose, cerebrosides, gangliosides, and mucoproteins. Deficiency of galactosyl-1-phosphate uridyltransferase (GALACTOSE-1-PHOSPHATE URIDYL-TRANSFERASE DEFICIENCY DISEASE) causes an error in galactose metabolism called GALACTOSEMIA, resulting in elevations of galactose in the blood.Drugs, Chinese Herbal: Chinese herbal or plant extracts which are used as drugs to treat diseases or promote general well-being. The concept does not include synthesized compounds manufactured in China.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.GlucosamineCrystallization: The formation of crystalline substances from solutions or melts. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Affinity Labels: Analogs of those substrates or compounds which bind naturally at the active sites of proteins, enzymes, antibodies, steroids, or physiological receptors. These analogs form a stable covalent bond at the binding site, thereby acting as inhibitors of the proteins or steroids.Cross Reactions: Serological reactions in which an antiserum against one antigen reacts with a non-identical but closely related antigen.Plants, Medicinal: Plants whose roots, leaves, seeds, bark, or other constituent parts possess therapeutic, tonic, purgative, curative or other pharmacologic attributes, when administered to man or animals.Electrophoresis, Disc: Electrophoresis in which discontinuities in both the voltage and pH gradients are introduced by using buffers of different composition and pH in the different parts of the gel column. The term 'disc' was originally used as an abbreviation for 'discontinuous' referring to the buffers employed, and does not have anything to do with the shape of the separated zones.Fluorometry: An analytical method for detecting and measuring FLUORESCENCE in compounds or targets such as cells, proteins, or nucleotides, or targets previously labeled with FLUORESCENCE AGENTS.Edetic Acid: A chelating agent that sequesters a variety of polyvalent cations such as CALCIUM. It is used in pharmaceutical manufacturing and as a food additive.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.Immune Sera: Serum that contains antibodies. It is obtained from an animal that has been immunized either by ANTIGEN injection or infection with microorganisms containing the antigen.

The gas-liquid chromatograph and the electron capture detection in equine drug testing. (1/6149)

Three gas-liquid chromatographic (G.L.C.) procedures discussed have been designed around the four "esses" of detection tests--speed, sensitivity, simplicity, and specificity. These techniques are admirably applicable to the very low plasma drug levels encountered in blood testing under pre-race conditions. The methods are equally applicable to post-race testing procedures, where both blood and urine samples are tested. Drugs can only rarely be detected by the electron capture detector (E.C.D.) without a prior derivatization step, which conveys to the drug(s) high electron affinity. Because of broad applicability, two derivatizing agents, heptafluorobutyric (HFBA) and pentafluorpropionic (PFPA) anhydrides are employed. The three techniques, allowing broad coverage of various drug classes are: 1) direct derivatization of drugs to form strongly electron capturing amides and esters. 2) reductive fragmentation of drugs with lithium aluminum hydride to form alcohols, with conversion to ester derivatives. 3) oxidative fragmentation of drugs with potassium dichromate to form derivatizable groups, followed by direct derivatization.  (+info)

Research and identification of tranquillizers - use of retention index. (2/6149)

At the request of the Service des Haras, our laboratory works on the toxicological problems of the sport-horse. These studies have resulted in the setting up of an anti-doping control for equestrian competitions of various types, not only flat racing. During events, horses, must be calm and docile to the riders' order. Frequently, the latter use tranquillizers to try and win events. The analytical method for the research and identification of these compounds is described. The technique involves successively: 1. alkalinisation of the sample - saliva, blood or urine after enzymatic hydrolysis. 2. extraction with diethyl ether - the recovery is 70% to 90% depending upon the drug. 3. determination by gas-liquid chromatography with use of a retention index for qualitative analysis. We can detect up to fifteen tranquillizers in any one sample, even when present at such low concentrations as found in saliva. The use of the retention index is a reliable method for qualitative analysis. For example, the method has been used for three years, during which period the rentention index of acetylpromazine remained at 3240 +/- 7. The chromatographic analysis was performed on 3% OV-17 at 290 degrees. The chromatographic analysis has been performed by three columns of different polarity (OV-1; OV-17; SP-2250). If on the three columns, the retention index of one peak is the same as that of the tranquilizer, a further confirmation is made with the use of a thermionic detector specific for nitrogenous drugs. In conclusion, this method which is sufficiently precise and specific has been used for anti-doping control.  (+info)

An improved method for the structural profiling of keratan sulfates: analysis of keratan sulfates from brain and ovarian tumors. (3/6149)

A previously developed method for the structural fingerprinting of keratan sulfates (Brown et al., Glycobiology, 5, 311-317, 1995) has been adapted for use with oligosaccharides fluorescently labeled with 2-aminobenzoic acid following keratanase II digestion. The oligosaccharides are separated by high-pH anion-exchange chromatography on a Dionex AS4A-SC column. This methodology permits quantitative analysis of labeled oligosaccharides which can be detected at the sub-nanogram ( approximately 100 fmol) level. Satisfactory calibration of this method can be achieved using commercial keratan sulfate standards. Keratan sulfates from porcine brain phosphocan and human ovarian tumors have been examined using this methodology, and their structural features are discussed.  (+info)

Metabolism of the new liposomal anticancer drug N4-octadecyl-1-beta-D-arabinofuranosylcytosine in mice. (4/6149)

Metabolism and excretion of the new antitumor drug N4-octadecyl-1-beta-D-arabinofuranosylcytosine (NOAC) was investigated in mice. Mice were injected i.v. with tritium-labeled liposomal NOAC (4 micromol/mouse). Analysis of HPLC-purified extracts of liver homogenates by liquid chromatography coupled with mass spectrometry revealed only the presence of unmetabolized drug. To study the excretion of the administered drug, mice were injected with tritium-labeled liposomal NOAC or as comparison with 1-beta-D-arabinofuranosylcytosine (ara-C; 4 micromol/mouse) and housed up to 48 h in metabolic cages. Urine and feces were collected at different time points and the kinetics of excreted radioactivity were determined. After 48 h, 39% of the injected [5-3H]NOAC radioactivity was excreted in urine and 16% in feces, whereas ara-C radioactivity was only found in urine with 48% of the injected dose. Feces extracts and urine were purified by HPLC and radioactive fractions were further analyzed by liquid chromatography coupled with mass spectrometry. The radioactivity of feces extracts of NOAC-treated mice was composed of unmetabolized NOAC, hydroxylated NOAC (NOAC + OH), its sulfated derivative (NOAC + OSO3H), and unidentified metabolites, whereas in urine, the hydrophilic molecules ara-C and ara-U were found. During the period of 48 h only 2% of the injected NOAC was eliminated in its unmetabolized form, whereas 25% was identified as main metabolite ara-C. Urine collected during 48 h in ara-C-treated mice contained 33% of the injected dose as unmetabolized drug and 13% as the main metabolite ara-U. Thus, NOAC is metabolized by two major pathways, one leading to the hydrophilic metabolites ara-C and ara-U and the other to hydroxylated and sulfated NOAC.  (+info)

Studies on cytochrome P-450-mediated bioactivation of diclofenac in rats and in human hepatocytes: identification of glutathione conjugated metabolites. (5/6149)

The nonsteroidal anti-inflammatory drug diclofenac causes a rare but potentially fatal hepatotoxicity that may be associated with the formation of reactive metabolites. In this study, three glutathione (GSH) adducts, namely 5-hydroxy-4-(glutathion-S-yl)diclofenac (M1), 4'-hydroxy-3'-(glutathion-S-yl)diclofenac (M2), and 5-hydroxy-6-(glutathion-S-yl)diclofenac (M3), were identified by liquid chromatography-tandem mass spectrometry analysis of bile from Sprague-Dawley rats injected i.p. with a single dose of diclofenac (200 mg/kg). These adducts presumably were formed via hepatic cytochrome P-450 (CYP)-catalyzed oxidation of diclofenac to reactive benzoquinone imines that were trapped by GSH conjugation. In support of this hypothesis, M1, M2, and M3 were generated from diclofenac in incubations with rat liver microsomes in the presence of NADPH and GSH. Increases in adduct formation were observed when incubations were performed with liver microsomes from phenobarbital- or dexamethasone-treated rats. Adduct formation was inhibited by polyclonal antibodies against CYP2B, CYP2C, and CYP3A (40-50% inhibition at 5 mg of IgG/nmol of CYP) but not by an antibody against CYP1A. Maximal inhibition was obtained when the three inhibitory antibodies were used in a cocktail fashion (70-80% inhibition at 2.5 mg of each IgG/nmol of CYP). These data suggest that diclofenac undergoes biotransformation to reactive metabolites in rats and that CYP isoforms of the 2B, 2C, and 3A subfamilies are involved in this bioactivation process. With respect to CYP2C isoforms, rat hepatic CYP2C7 and CYP2C11 were implicated as mediators of the bioactivation based on immunoinhibition studies using antibodies specific to CYP2C7 and CYP2C11. Screening for GSH adducts also was carried out in human hepatocyte cultures containing diclofenac, and M1, M2, and M3 again were detected. It is possible, therefore, that reactive benzoquinone imines may be formed in vivo in humans and contribute to diclofenac-mediated hepatic injury.  (+info)

Ethyl glucuronide--a marker of alcohol consumption and a relapse marker with clinical and forensic implications. (6/6149)

Ethyl glucuronide (EtG) is a non-volatile, water-soluble, direct metabolite of ethanol that can be detected in body fluids and hair. We investigated urine and serum samples from three patient groups: (1) 33 in-patients in acute alcohol withdrawal; (2) 30 detoxified in-patients (treated for at least 4 weeks) from a 'motivation station'; and (3) 43 neuro-rehabilitation patients (non-alcoholics; most of them suffering from stroke, traumatic brain injury, Parkinson's disease etc.) using gas chromatography/mass spectrometry (GC/MS) with deuterium-labelled EtG as the internal standard and additionally in the second group of patients using liquid chromatography (LC/MS-MS). We found no correlation between the concentration of EtG in urine at hospitalization and the blood-ethanol concentration (r = 0.17), the time frame of detection (r = 0.5) or the total amount of clomethiazole required for the treatment of withdrawal symptoms (r = 0.28). In four out of 30 in-patients from the 'motivation station'--where neither clinical impression nor routine laboratory findings gave indications of relapse--concentrations of EtG in urine ranged between 4.2 and 196.6 mg/l. EtG concentrations in urine of between 2.89 and 23.49 mg/l were found in seven out of 43 neuro-rehabilitation patients using GC/MS. The GC/MS and the LC/MS-MS results showed a correlation of 0.98 with Pearson's correlation test and 1.0 with Spearman's correlation test. We suggest that EtG is a marker of alcohol consumption that can be detected for an extended time period after the complete elimination of alcohol from the body. When used as a relapse marker with a specific time frame of detection intermediate between short- and long-term markers, EtG fills a clinically as well as forensically important gap. Its specificity and sensitivity exceed those of all other known ethanol markers.  (+info)

Lignocellulose degradation by Phanerochaete chrysosporium: purification and characterization of the main alpha-galactosidase. (7/6149)

The main alpha-galactosidase was purified to homogeneity, in 30% yield, from a solid culture of Phanerochaete chrysosporium on 1 part wheat bran/2 parts thermomechanical softwood pulp. It is a glycosylated tetramer of 50 kDa peptide chains, which gives the N-terminal sequence ADNGLAITPQMG(?W)NT(?W)NHFG(?W)DIS(?W)DTI. It is remarkably stable, with crude extracts losing no activity over 3 h at 80 degrees C, and the purified enzyme retaining its activity over several months at 4 degrees C. The kinetics of hydrolysis at 25 degrees C of various substrates by this retaining enzyme were measured, absolute parameters being obtained by active-site titration with 2',4',6'-trinitrophenyl 2-deoxy-2, 2-difluoro-alpha-D-galactopyranoside. The variation of kcat/Km for 1-naphthyl-alpha-D-galactopyranoside with pH is bell-shaped, with pK1=1.91 and pK2=5.54. The alphaD(V/K) value for p-nitrophenyl-alpha-D-glucopyranoside is 1.031+/-0.007 at the optimal pH of 3.75 and 1.114+/-0.006 at pH7.00, indicating masking of the intrinsic effect at optimal pH. There is no alpha-2H effect on binding galactose [alphaD(Ki)=0.994+/-0.013]. The enzyme hydrolyses p-nitrophenyl beta-L-arabinopyranoside approximately 510 times slower than the galactoside, but has no detectable activity on the alpha-D-glucopyranoside or alpha-D-mannopyranoside. Hydrolysis of alpha-galactosides with poor leaving groups is Michaelian, but that of substrates with good leaving groups exhibits pronounced apparent substrate inhibition, with Kis values similar to Km values. We attribute this to the binding of the second substrate molecule to a beta-galactopyranosyl-enzyme intermediate, forming an E.betaGal. alphaGalX complex which turns over slowly, if at all. 1-Fluoro-alpha-D-galactopyranosyl fluoride, unlike alpha-D-galactopyranosyl fluoride, is a Michaelian substrate, indicating that the effect of 1-fluorine substitution is greater on the first than on the second step of the enzyme reaction.  (+info)

Oxidized low-density lipoprotein as a delivery system for photosensitizers: implications for photodynamic therapy of atherosclerosis. (8/6149)

Photodynamic therapy is a promising new strategy in the treatment of cardiovascular diseases. Photodynamic therapy for vascular diseases may be improved by the specific delivery of photosensitizers to the atherosclerotic lesion. In this study, we studied whether oxidatively modified low-density lipoprotein (OxLDL) could be used as a specific carrier for photosensitizers, thereby using the scavenger receptor expressed on macrophages as a target. The photosensitizer aluminum phthalocyanine chloride (AlPc) was incorporated into OxLDL, and its photodynamic effects were studied. Macrophages (RAW 264.7) were incubated with various concentrations of OxLDL-AlPc for different periods. After illumination of the cells with red light, cytotoxicity was observed that was dependent on the time of illumination and incubation. Macrophages incubated with OxLDL-AlPc that were not illuminated revealed no cytotoxicity. The uptake of the OxLDL-AlPc complexes was mediated by scavenger receptors expressed on macrophages. In the presence of the polyanion polyinosinic acid, a specific ligand for scavenger receptors, no cytotoxicity could be observed. Serum incubations of the OxLDL-AlPc complexes revealed that these complexes stay intact after incubation. No redistribution of AlPc to other plasma (lipo-) proteins could be detected, and 80-90% of the AlPc remained associated with the OxLDL particle. These results indicate that OxLDL may function as a specific delivery system for photosensitizers to the scavenger receptors expressed on the macrophages in the atherosclerotic lesion, increasing the beneficial effects of photodynamic therapy for cardiovascular diseases.  (+info)

Tea is the second most consumed beverage in the world and its consumption has been associated with numerous potential health benefits. Factors such as fermentation methods, geographical origin and season can affect the primary and secondary metabolite composition of tea. In this study, a hydrophilic interaction liquid chromatography (HILIC) method coupled to high resolution mass spectrometry in both positive and negative ionisation modes was developed and optimised. The method when combined with principal component analysis to analyse three different types of tea, successfully distinguished samples into different categories, and provided evidence of the metabolites which differed between them. The accurate mass and high resolution attributes of the mass spectrometric data were utilised and relative quantification data were extracted post-data acquisition on 18 amino acids, showing significant differences in amino acid concentrations between tea types and countries. This study highlights the ...
A method for the analysis of dextran-1 has been developed using hydrophilic interaction liquid chromatography (HILIC) with charged corona aerosol detection (CCAD) as a potential alternative to the size exclusion chromatography method described in the European Pharmacopoeia (EP). Click to read more...
Differential mobility spectrometry for improved selectivity in hydrophilic interaction liquid chromatography-tandem mass spectrometry analysis of paralytic shellfish toxins
article{167611, author = {Van de Wiele, Mieke and De Wasch, Katia and VERCAMMEN, J and COURTHEYN, D and De Brabander, Hubert and Impens, Sandra}, issn = {0021-9673}, journal = {JOURNAL OF CHROMATOGRAPHY A}, language = {eng}, number = {2}, pages = {203--209}, title = {Determination of 16 beta-hydroxystanozolol in urine and faeces by liquid chromatography-multiple mass spectrometry.}, volume = {904}, year = {2000 ...
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Simultaneous determination of β-hydroxybutyrate and β-hydroxy-β-methylbutyrate in human whole blood using hydrophilic interaction liquid chromatography electrospray tandem mass ...
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A recently developed stable isotope dilution liquid chromatography-multiple reaction/mass spectrometry method to quantify focal adhesion kinase (FAK) activation loop phosphorylation was used to study endogenous Src kinase activity. This revealed that bis-phosphorylated pTyr576/Tyr577-FAK was a biomarker of Src activity and inactivation in vitro and in cell culture. Mouse embryonic fibroblasts (MEFs) expressing endogenous Src family kinases contained 65% unmodified Tyr576/Tyr577, 33% mono-phosphorylated-pTyr576-FAK, and 6% bis-phosphorylated-pTyr576/pTyr577-FAK. In contrast, MEFs expressing oncogenic Y529FSrc contained 38% unmodified Tyr576/Tyr577-FAK, 29% mono-phosphorylated-pTyr576-FAK, and 19% bis-phosphorylated-pTyr576/pTyr577-FAK. This new method has made it possible to accurately determine the absolute amounts of FAK phosphorylation that occur after Src inhibition in cell culture and in vitro with increasing concentrations of the Src inhibitor ...
Mitochondrial dysfunction plays a role in a wide range of diseases resulting in an enormous public health burden. The goal of this thesis is to identify metabolic pathways that are disrupted in response to mitochondrial insults. A large proportion of this work is based on the generation of stable isotope labelled metabolites to allow for the rigorous quantification of intracellular metabolites by liquid chromatography-mass spectrometry. Once developed, this methodology was employed in cell culture models initially to characterize an unidentified acyl-CoA thioester induced by propionate metabolism. This novel pathway was identified as the direct formation of 2-methyl-2-pentenoyl-CoA, and using isotopic labeling by metabolic precursors served as a critical component to this pathway elucidation. These same techniques were then applied to studying rotenone, a mitochondrial complex I inhibitor associated with Parkinsonâ??s disease. Previous work by our group has shown that rotenone inhibits components of
PubMed Central Canada (PMC Canada) provides free access to a stable and permanent online digital archive of full-text, peer-reviewed health and life sciences research publications. It builds on PubMed Central (PMC), the U.S. National Institutes of Health (NIH) free digital archive of biomedical and life sciences journal literature and is a member of the broader PMC International (PMCI) network of e-repositories.
In a preliminary study in healthy subjects, the investigators determined the pharmacokinetic and pharmacodynamic of enteric-coated acetylsalicylic acid (ASA) (Adiro 100 mg, Bayer), and the variability (coefficient of variation), accuracy and precision of a novel biomarker of ASA action, i.e., quantification of the extent of COX-1 acetylation at serine-529, using a stable isotope dilution liquid chromatography multiple reaction monitoring/mass spectrometry (LC-MS) technique.. Now, the investigators will perform a clinical study in individuals undergoing Colorectal cancer (CRC) to validate the hypothesis that that low-dose ASA given once daily is acting primarily by selectively acetylating platelet COX-1 and suppressing its activity throughout the 24-hour dosing interval. In contrast, it is expected that the inhibitory effect on extra-platelet sources of COX-1 will be short-lasting, if any, affecting only partially COX-1, and this effect will be completely reversed at 24 hours after dosing. This ...
A novel bioanalytical method was developed and validated for the quantitative determination of erlotinib in human plasma by using the supported liquid extraction (SLE) sample cleanup coupled with hydrophilic interaction liquid chromatography and tandem mass spectrometric detection (HILIC-MS/MS). The SLE extract could be directly injected into the HILIC-MS/MS system for analysis without the solvent evaporation and reconstitution steps. Therefore, the method is simple and rapid. In the present method, erlotinib-d6 was used as the internal standard. The SLE extraction recovery was 101.3%. The validated linear curve range was 2 to 2,000 ng/mL based on a sample volume of 0.100-mL, with a linear correlation coefficient of | 0.999. The validation results demonstrated that the present method gave a satisfactory precision and accuracy: intra-day CV | 5.9% (
Protein recovery is crucial for shotgun metaproteomics to study the in situ functionality of microbial populations from complex biofilms but still poorly addressed by far. To fill this knowledge gap, we systematically evaluated the sample preparation with extraction buffers comprising four detergents for the metaproteomics analysis of a terephthalate-degrading methanogenic biofilm using an on-line two-dimensional liquid chromatography tandem mass spectrometry (2D-LC-MS/MS) system. Totally, 1018 non-repeated proteins were identified with the four treatments. On the whole, each treatment could recover the biofilm proteins with specific distributions of molecular weight, hydrophobicity, and isoelectric point. The extraction buffers containing zwitterionic and anionic detergents were found to harvest the proteins with better efficiency and quality, allowing identification up to 76.2% of total identified proteins with the LC-MS/MS analysis. According to the annotation with a relevant metagenomic
Lin XH,WangQuancai,Yin PY,et al. A method for handling metabonomics data from liquid chromatography mass spectrometry: combinational use of support vector machine recursive feature elimination, genetic algorithm and random forest for feature selection[J]. Metabolomics,2011,4(待补充):549 ...
Agilent Technologies Inc. announced analyses of carbamates and phenyl ureas using liquid chromatography/mass spectrometry (LC/MS). The sources for these tes
Currently, statins are the only drugs acting on the mammalian isoprenoid pathway. The mammalian genes in this pathway are not easily amenable to genetic manipulation. Thus, it is difficult to study the effects of the inhibition of various enzymes on the intermediate and final products in the isoprenoid pathway. In fission yeast, antifungal compounds such as azoles and terbinafine are available as inhibitors of the pathway in addition to statins, and various isoprenoid pathway mutants are also available. Here in these mutants, treated with statins or antifungals, we quantified the final and intermediate products of the fission yeast isoprenoid pathway using liquid chromatography-mass spectrometry/mass spectrometry. In hmg1-1, a mutant of the gene encoding 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR), ergosterol (a final sterol product), and squalene (an intermediate pathway product), were decreased to approximately 80% and 10%, respectively, compared with that of wild-type cells. Consistently
Methylation aberrations play an important role in many metabolic disorders including cancer. Methylated metabolites are direct indicators of metabolic aberrations, and currently, there is no liquid chromatography-mass spectrometry (LC-MS) based method available to cover all classes of methylated metabolites at low detection limits. In this study, we have developed a method for the detection of methylated metabolites, and its biological application. In this approach, we used a HILIC based HPLC method combined with MS to measure methylated organic acids, amino acids, and nucleotides. These metabolites were separated from each other by their hydrophobic interactions and analyzed using a targeted metabolomics approach by single reaction monitoring in positive and negative modes of electrospray ionization. These metabolites were quantified, and the interday reproducibility was ,10% relative standard deviation. Furthermore, by applying this method, we identified high levels of methylated metabolites ...
Polysaccharides from Baizhu were separated by preparative hydrophilic interaction liquid chromatography on an XAmide column and its components were characterised as inulin-type polysaccharides with structures of alpha-D-glucopyranosyl-[-(1 -> 2) -beta-D-fructofuranosyl-](n-1)-(1 -> 2) -beta-D-fructofuranoside (n=3-20) by a combinatory application of electrospray-ionisation mass spectrometry, nuclear magnetic resonance and IR, as well as the chemical analysis of monosaccharide composition. In addition, the contents of nystose and 1F-fructofranosylnystose in the crude and purified Baizhu polysaccharides were determined to be 5.81%, 4.92% and 0.70%, 0.84% (w/w), respectively. In addition, MTT assay indicated that the Baizhu polysaccharides could effectively promote spleen lymphocyte transformation for the enhancement of organism immunity. It is for the first time that inulin-type polysaccharides were discovered in Baizhu and its immuno-enhancing activity was reported, which is a vigorous evidence ...
Immunoassay has been used to measure the blood concentration of drugs, steroids, and vitamin D. However, the immunoassay methods have limitations related to the differences of the methods, variation in the reagents, sensitivity, and specificity. Recently liquid chromatograph mass spectrometers (LC/MS/MS) are being used to improve analytical accuracy and precision based on its superior specificity. On the other hand, in the analysis of biological samples like serum by LC/MS/MS, sample preparation is required to carry out protein precipitation and sample dilution. These procedures cause a risk of variations and mistakes, depending on the operators procedure. In this article, the validation of 25-OH vitamin D2/D3 and steroids in serum using a fully automated sample preparation LC/MS/MS system is described.. Keywords: Sample preparation, Vitamin D, Steroids, LC/MS/MS. ...
LIQUID CHROMATOGRAPHY-MASS SPECTROMETRY FOR THE STUDY OF ARACHIDONIC ACID METABOLITES Xiaojing Liu Ian A. Blair, PhD Arachidonic acid (AA) oxidation metabolism has been an important research topic for decades, and numerous oxidation products as well as enzymes involved in AA metabolism together with their downstream metabolites have been identified, although unknown pathways still remain to be characterized. In the present a study a new AA metabolite, 11-oxo-eicosatetraenoic acid (ETE), generated from a major product of cyclooxygenase (COX-2), 11(R)-hydroxyeicosatetraenoic acid (HETE), through 15-hydroxyprostaglandine dehydrogenase (15-PGDH)-mediated oxidation. 11-Oxo-ETE was found to have an anti-proliferative effect on human umbilical vein endothelial cells (HUVECs), with a similar IC50 to a well- known anti-inflammatory mediator, 15-deoxy-12,14-prostaglandin J2 (15d-PGJ2). It was also found that 11-oxo-ETE could be inactivated through the glutathione-S-transferase (GST)/glutathione (GSH) pathway
Fibroblast growth factor 23 (FGF23) is a bone-derived hormone that controls blood phosphate levels by increasing renal phosphate excretion and reducing 1,25-dihydroxyvitamin D3 [1,25(OH)2D] production. Disorders of FGF23 homeostasis are associated with significant morbidity and mortality, but a fundamental understanding of what regulates FGF23 production is lacking. Because the kidney is the major end organ of FGF23 action, we hypothesized that it releases a factor that regulates FGF23 synthesis. Using aptamer-based proteomics and liquid chromatography-mass spectrometry-based (LC-MS-based) metabolomics, we profiled more than 1600 molecules in renal venous plasma obtained from human subjects. Renal vein glycerol-3-phosphate (G-3-P) had the strongest correlation with circulating FGF23. In mice, exogenous G-3-P stimulated bone and bone marrow FGF23 production through local G-3-P acyltransferase-mediated (GPAT-mediated) lysophosphatidic acid (LPA) synthesis. Further, the stimulatory effect of G-3-P ...
The Sustainable Environment Research Centre (SERC) undertakes national and world-leading research into waste treatment and the sustainable production of energy from waste and grown biomass. To achieve this, considerable investment has been made into the facilities available to researchers and students.. Waste Water Treatment and Fermentative Hydrogen Production Laboratory. This is a dedicated laboratory for the development and testing of lab scale bio-reactors. Research undertaken includes the optimisation of hydrogen and methane production from various waste substrates, and has been key to the successful development of several field-scale systems.. Ultra Performance Liquid Chromatography Laboratory. SERC is one of only a handful of sites in the UK to be undertaking environmental research using state-of-the-art Ultra Performance Liquid Chromatography / Mass Spectrometry (UPLC-MS). This analytical method provides highly accurate results to nano-gram concentrations. The equipment is currently ...
Dittmar, T. , Whitehead, K. , Minor, E. C. and Koch, B. (2007): Tracing terrigenous dissolved organic matter and its photochemical decay in the ocean by using liquid chromatography/mass spectrometry , Marine chemistry ...
LC/MS analysis of the chimeric OMT reaction products using laudanosoline as a substrate. Upper panel; OMT reactions and their predicted ions in LC/MS analysis.
...With the advent of liquid chromatography/ mass spectrometry and inform... Abstract ... The Q TRAP instrument is based on a triple quadrupole ion path and is... ...,Simultaneously,characterizing,and,quantifying,chloramphenicol,and,its,metabolite,using,LC/MS/MS,biological,advanced biology technology,biology laboratory technology,biology device technology,latest biology technology
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This application brief demonstrate the unique ability of charged surface hybrid (CSH Technology) C18 to produce high peak capacity peptide separations at high mass loads in nanoLC chromatography
Liquid chromatography with tandem mass spectrometry (LC-MS/MS) based quantitative proteomics provides the relative different protein abundance in healthy and disease-afflicted patients, which offers the information for molecular interactions, signaling pathways, and biomarker identification to serve the drug discovery and clinical research. Typical analysis workflow begins with the peptide feature detection and intensity calculation from LC-MS map. We are the first to propose a deep learning based model, DeepIso, that combines recent advances in Convolutional Neural Network (CNN) and Recurrent Neural Network (RNN) to detect peptide features of different charge states, as well as, estimate their intensity. Existing tools are designed with limited engineered features and domain-specific parameters, which are hardly updated despite a huge amount of new coming proteomic data. On the other hand, DeepIso consisting of two separate deep learning based modules, learns multiple levels of representation ...
Due to the high prescription of antidepressants and their frequent involvement in clinical and forensic intoxications, reliable analytical techniques for identification and quantification of these...
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We are skilled in the development of analytical methods for determination of trace amounts of tracked impurities. For our customers we usually develop methods for assessment of toxic impurities at levels much below those demanded by corresponding regulatory authorities. Often we deal with systems where the target components are susceptible to decomposition or can react easily with the active ingredient or sample matrix. Despite these challenges, we continue to succeed with the development of such methods. For this purpose we use LC/MS (HPLC 2695 Alliance(Waters)/LTQ (Thermo-Finnigan)) or GC/MS (7890A/5975C(Agilent Technologies)) technique. Routinely, we are able to achieve a sensitivity at ppm levels on both these systems which is usually sufficient for most pharmaceutical applications.. When necessary, we benefit from cooperation with our bioanalytical department. There we may use several (mostly triple-quadrupole) LC/MS instruments in tandem offering a sensitivity in the order of units ...
Me Time Tag, o leapsa creata de Essie Button si Amelia ce contine 10 intrebari legate preferintele pentru "me-time", timpul pe care ni-l acordam pentru noi.
Citation: Pawlosky, R.J., Flanagan, V.P., Novotny Dura, J. 2000. A sensitive procedure for the study of beta-carotene-d8 metabolism in humans using liquid chromatography-mass spectrometry. Journal of Lipid Research. 41:1027-1031. Interpretive Summary: This report describes the development of a robust method for studying the metabolism of (stable hydrogen) deuterium- labeled-Beta-carotene in humans using liquid chromatography and mass spectrometry. Deuterium-labeled-Beta-carotene was extracted from human blood and injected onto a liquid chromatograph. The limit of detection was about 0.3 ng for deuterium-labeled-Beta-carotene. The compound was quantified over a concentration range of two orders of magnitude using an internal standard. The overall coefficient of variance (CV) for determining the concentration of deuterium-labeled-Beta-carotene from blood was 2.4%. Using this method, the concentration of deuterium-labeled-Beta-carotene was determined in the plasma of a subject who had consumed a ...
Anthias Consulting Trainer and Consultant Dr Giles Edwards is presenting a week-long course on liquid chromatography-mass spectrometry (LC-MS) in Nairobi, Kenya.
BioAssay record AID 755005 submitted by ChEMBL: Permeability from basolateral to apical side of human Caco2 cells at 10 uM after 30 to 90 mins by LC-MS/MS analysis.
Agilent Technologies has introduced the latest addition to its portfolio of solutions for biopharmaceutical labs the Agilent 6545XT AdvanceBio LCQ-TOF MS system. Optimized to address analytical workflows commonly used in biopharma, the new LCQ-TOF MS system combines high-performance liquid chromatography HPLC with robust quadrupole time-of-flight...
UCL Discovery is UCLs open access repository, showcasing and providing access to UCL research outputs from all UCL disciplines.
Question - Suffering from IBS. Recurring digestion problem. Continued drinking with medication. Disease worsen. Surviving on liquid diet and probiotics. Medication? . Ask a Doctor about uses, dosages and side-effects of Ofloxacin, Ask a Gastroenterologist
BANTAN POLAK, Tjaša, MITROVIĆ, Bojan, MILAČIČ, Radmila. The use of fast protein liquid chromatography with ICP-OES and ES-MS-MS detection for the determination of various forms of aluminium in the roots of Chinese cabbage. Anal. chim. acta. [Print ed.], 2005, vol. 540, no. 1, str. 83-89 ...
Sigma-Aldrich offers abstracts and full-text articles by [Atsuhiko Toyama, Hidewaki Nakagawa, Koichi Matsuda, Nobuhisa Ishikawa, Nobuoki Kohno, Yataro Daigo, Taka-Aki Sato, Yusuke Nakamura, Koji Ueda].
The AC Extraction Plate from Tecan is an automation-friendly solution designed to streamline sample preparation for LC-MS analysis of small molecules.
Li Y (2007) CST Curation Set: 2888; Year: 2007; Biosample/Treatment: cell line, A549/untreated &,, TSA; Disease: lung cancer; SILAC: -; Specificities of Antibodies Used to Purify Peptides prior to LCMS: acK ...
TY - JOUR. T1 - Optimized extraction of phospholipids and lysophospholipids for nanoflow liquid chromatography-electrospray ionization-tandem mass spectrometry. AU - Byeon, Seul Kee. AU - Lee, Ju Yong. AU - Moon, Myeong Hee. PY - 2012/1/21. Y1 - 2012/1/21. N2 - The efficiencies of four different methods for the extraction of phospholipids (PLs) and lysophospholipids (LPLs) from human plasma samples were examined by comparing extraction recovery values using nanoflow liquid chromatography-electrospray ionization-mass spectrometry (nLC-ESI-MS). For recovery measurements, six PL and six LPL standards of different head groups were spiked into a human plasma sample, and the peak areas of each individual species after extraction were measured from the chromatograms of the nLC-ESI-MS runs. Recovery was calculated by comparing the peak area of an extracted standard species with that of the same species spike after extraction of the same plasma sample. For lipid extraction, four different extraction ...
Florentina Laura Chiriac, Iuliana Paun, Florinela Pirvu, Luoana Florentina Pascu, Marcela Niculescu, Toma Galaon - Liquid Chromatography Tandem Mass Spectrometry Method for Ultra-Trace Analysis of Organic UV Filters in Environmental Water Samples
TY - JOUR. T1 - Comparison of gas chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry methods to quantify α-tocopherol and αtocopherolquinone levels in human plasma. AU - Mottier, Pascal. AU - Gremaud, Eric. AU - Guy, Philippe A.. AU - Turesky, Robert J.. PY - 2002/2/1. Y1 - 2002/2/1. N2 - Two mass spectrometric methods were established for the quantitative analyses of α-tocopherol (TH) and its oxidation product α-tocopherolquinone (TQ) in human plasma. Both methods make use of isotopically labeled internal standards of different levels of deuteration (d3-TH and d6-TQ). Plasma (100 μl) was saponified in the presence of a mixture of antioxidants, and then TH and TQ were extracted with hexane. With the GC-MS method, the analytes were first converted into O-trimethylsilyl derivatives before analysis in the selective ion monitoring mode. The derivatization procedure led to the quantitative conversion of TQ into the O-trimethylsilyl derivative of ...
We have demonstrated an on-line laser ablation sampling system and coupling of the system to liquid chromatography (LC) using an infrared (IR) laser to ablate and transfer materials into a flowing solvent stream. With this approach, samples are depos
RATIONALE Neonicotinoids (NNIs) are the fastest expanding group of pesticides in the world over the last two decades; however, they may be a significant contributing factor to bee mortality. The widespread use of NNIs makes it critical to monitor their residuals in the environment. Published methods for NNI analysis are mainly focused on agricultural and food products, and many of them only measured a portion of the commercially available NNIs. METHODS Utilizing a biphenyl stationary-phase column, a sensitive liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed to determine eight NNIs, including acetamiprid, clothianidin, dinotefuran, flonicamid, imidacloprid, nitempyram, thiacloprid and thiamethoxam in environmental water. Two multiple reaction monitoring (MRM) transitions were monitored for each compound to ascertain true positive identification. Isotope-labelled NNIs, d3-acetamiprid, d3-clothianidin, d4-imidacloprid and d3-thiamethoxam, were used to compensate for
Abstract: A liquid chromatography tandem mass spectrometry method was developed for quantifying ten cannabinoids in oral fluid (OF). This method utilizes OF collected by the Quantisal device and concurrently quantifies cannabinol (CBN), cannabidiol (CBD), Δ9-tetrahydrocannabinol (THC), 11-hydroxy-Δ9-THC (11-OH-THC), 11-nor-9-carboxy-Δ9-THC (THC-COOH), 11-nor-9-carboxy-Δ9-THC glucuronide (THC-COOH-gluc), Δ9-THC glucuronide (THC-gluc), cannabigerol (CBG), tetrahydrocannabiverin (THCV), and Δ9-tetrahydrocannabinolic acid A (THCA-A). Solid phase extraction was optimized using Oasis Prime HLB 30 mg 96-well plates. Cannabinoids were separated by liquid chromatography over a BEH C18 column and detected by a Waters TQ-S micro tandem mass spectrometer. The lower limits of quantification (LLOQ) were 0.4 ng/mL for CBN, CBD, THC, 11-OH-THC, THC-gluc, and THCV; and 1.0 ng/mL for THC-COOH, THC-COOH-gluc, CBG and THCA-A. Linear ranges extended to 2000 ng/mL for THC and 200 ng/mL for all other analytes. ...
TY - JOUR. T1 - Analysis of metribuzin and its metabolites in livestock products and seafoods by liquid chromatography-tandem mass spectrometry. AU - Kai, Shigemi. AU - Akaboshi, Takeshi. AU - Waki, Masumi. AU - Fuzimaki, Teruhisa. AU - Kanazawa, Hideko. PY - 2011/2. Y1 - 2011/2. N2 - A method for simultaneous determination of metribuzin (MET) and three metribuzin metabolites in livestock products and seafoods by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed. MET and its metabolites were extracted from a sample with acetonitrile, followed by InertSepC18 and BondElut SAX cartridge cleanup. The LC separation was performed on a C18 column using 0.01 mol/L ammonium formate-acetonitrile-methanol (70 : 21 : 9) as the mobile phase and MS detection with both positive and negative ion electrospray ionization. The mean recoveries from 10 livestock products and seafoods were generally ,60%, and the relative standard deviations were ,20%.. AB - A method for simultaneous ...
PubMed comprises more than 30 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.
TY - JOUR. T1 - Validation of a high throughput method for serum/plasma testosterone using liquid chromatography tandem mass spectrometry (LC-MS/MS). AU - Singh, Ravinder Jit. PY - 2008/12/12. Y1 - 2008/12/12. N2 - Testosterone, the major androgenic hormone in humans, is commonly measured to aid in the diagnosis of clinical conditions related to its excess or deficiency. In addition, testosterone measurements are used to monitor testosterone replacement-, or antiandrogen therapy. Most commonly, automated direct immunoassays have been used to measure testosterone in human serum. Their advantage compared with other methodologies, lies in high- and rapid sample throughput with minimal human intervention. However, many automated testosterone immunoassays suffer from poor accuracy at the low concentration levels (,50 ng/dL) seen in women and children, or in men undergoing anti-androgen therapy. Our objective was to develop a LC-MS/MS method which measures testosterone in human serum while fulfilling ...
The obligate intracellular lifestyle of Plasmodium falciparum and the difficulties in obtaining sufficient amounts of biological material have hampered the study of specific metabolic pathways in the malaria parasite. Thus, for example, the pools of sugar nucleotides required to fuel glycosylation reactions have never been studied in-depth in well-synchronized asexual parasites or in other stages of its life cycle. These metabolites are of critical importance, especially considering the renewed interest in the presence of N-, O-, and other glycans in key parasite proteins. In this work, we adapted a liquid chromatography tandem mass spectrometry (LC-MS/MS) method based on the use of porous graphitic carbon (PGC) columns and MS-friendly solvents to quantify sugar nucleotides in the malaria parasite. We report the thorough quantification of the pools of these metabolites throughout the intraerythrocytic cycle of P. falciparum The sensitivity of the method enabled, for the first time, the targeted ...
Liquid chromatography tandem mass spectrometry is one of the most specific techniques available in clinical laboratories. In the past, immunoassays were the primary methodology for analysis of steroids in biological samples because they are rapid and easy to perform. However, these methods were shown to suffer from the lack of specificity for measuring many of the diagnostically important steroids. LC-MS/MS overcomes many of the limitations of immunoassays, enhances diagnostic utility of the testing, and expands diagnostic capabilities in endocrinology. In addition to the superior quality of the measurements, LC-MS/MS allows high throughput testing using small sample volume with minimal sample preparation, and frees the laboratory from dependence on suppliers of assay specific reagents. LC-MS/MS is being widely employed for routine measurement of steroids, and the methodology plays an important role in the standardization and harmonization of measurements among clinical laboratories.. ...
A stereoselective, sensitive and rapid liquid chromatography-tandem mass spectrometry (LC-MSMS) method for the determination of R-acenocoumarol and S-acenocoumarol in human plasma was developed and validated at IPRC bioanalytical labs. The procedure involved solid phase extraction of both enantiomers and their corresponding internal standard. The chromatographic separation was accomplished employing a chiral column and proper mobile phase. Detection was carried out using Waters Micromass® Quattro Premier mass spectrometer in multiple reaction monitoring (MRM) mode using turbo ion spray with negative ionization. The method was validated over a linear range of 0.40 - 40.00 ng/ml for R-acenocoumarol and 0.20 - 20.00 ng/ml for the S-acenocoumarol. Method validation covered different parameters such as linearity, accuracy, precision and stability. The method was successfully applied for the determination of R and S-acenocoumarol in plasma samples of 28 healthy subjects who participated in a pharmacokinetics
An improved method for determining levels of levosulpiride in human plasma using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed and validated. The protein precipitation method was used for plasma sample preparation. Levosulpiride and an internal standard (IS) were isocratically separated on a UPLC BEN C(18) column with a mobile phase of ammonium formate buffer (1 mM, adjusted to pH 3 with formic acid) and acetonitrile (60:40, v/v). MS/MS detection was performed by monitoring the parent -, daughter pair of levosulpiride and the IS at m/z 342 -, 112 and 329 -, 256, respectively. The method was linear from 2.5 to 200 ng/mL and exhibited acceptable precision and percent recovery. The method was successfully demonstrated in pharmacokinetic and bioequivalence studies of two levosulpiride oral formulations administered to healthy volunteers. When compared to the previous LC-MS methods, the proposed method is faster, well-validated, and uses lesser plasma ...
TY - JOUR. T1 - Effect of ionization modifiers on the simultaneous analysis of all classes of phospholipids by nanoflow liquid chromatography/tandem mass spectrometry in negative ion mode. AU - Bang, Dae Young. AU - Lim, Sangsoo. AU - Moon, Myeong Hee. PY - 2012/6/1. Y1 - 2012/6/1. N2 - The effect of ionization modifiers added to the mobile phase of nanoflow liquid chromatography-tandem mass spectrometry (nLC-ESI-MS 3) on the simultaneous analysis of all phospholipid (PL) classes in negative ion mode has been investigated. While MS analysis of most PL classes is carried out in negative ion mode, analysis of neutral polar (polar but electrically neutral) lipids like phosphatidylcholine (PC) and sphingomyelin (SM) is highly efficient in positive ion mode. Therefore, analysis of PL mixture samples often requires two separate runs in both positive and negative ion mode. In order to establish run conditions to carry out a single nLC-ESI-MS-MS for all PLs, the ionization efficiency of 13 different ...
SICHILONGO, Kwenga F.; MUCKOYA, Vallerie A. y NINDI, Mathew M.. A rapid and sensitive LC-MS/MS method for the determination of multi-class residues of antibiotics in chicken liver. S.Afr.j.chem. (Online) [online]. 2015, vol.68, pp.01-06. ISSN 1996-840X. http://dx.doi.org/10.17159/0379-4350/2015/v68a1.. A very sensitive, simple and cost-effective liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) method for the determination of multi-class antibiotics in chicken liver was developed. The drugs under consideration were sulfaguanidine and sulfamethazole, trimethoprim, tetracycline, chlortetracycline and tylosin. Linear calibrations were established for all the analytes and the R2 values ranged between 0.9990 and 0.9997. The limits of quantitation (LOQs) varied between 0.025 and 78.8 μg kg-1. The limit of detections (LODs) were better than those that have been reported for the same antibiotics in many instances in other studies and ranged between 0.010-31.5 μg kg-1 with the ...
SICHILONGO, Kwenga F.; MUCKOYA, Vallerie A. e NINDI, Mathew M.. A rapid and sensitive LC-MS/MS method for the determination of multi-class residues of antibiotics in chicken liver. S.Afr.j.chem. (Online) [online]. 2015, vol.68, pp.01-06. ISSN 1996-840X. http://dx.doi.org/10.17159/0379-4350/2015/v68a1.. A very sensitive, simple and cost-effective liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) method for the determination of multi-class antibiotics in chicken liver was developed. The drugs under consideration were sulfaguanidine and sulfamethazole, trimethoprim, tetracycline, chlortetracycline and tylosin. Linear calibrations were established for all the analytes and the R2 values ranged between 0.9990 and 0.9997. The limits of quantitation (LOQs) varied between 0.025 and 78.8 μg kg-1. The limit of detections (LODs) were better than those that have been reported for the same antibiotics in many instances in other studies and ranged between 0.010-31.5 μg kg-1 with the ...
Busulfan is an alkylating agent widely used in the ablation of bone marrow cells before hematopoietic stem cell transplant. Due to large intraindividual and interindividual variations, and narrow therapeutic window, therapeutic drug monitoring of busulfan is warranted. A quick and reliable HPLC-MS/MS method was developed for the assay of plasma busulfan. HPLC involved C18 column, and MS/MS was used in electrospray ionization (ESI) positive mode. Quantitation and identification of busulfan was made using various multiple reactions monitoring (MRMs). Isotopic labeled busulfan-d8 was used as the internal standard. The method is linear from 50 to 2500 ng/mL and has with-in run and between-run imprecision of |10|%.
Sigma-Aldrich offers abstracts and full-text articles by [Gabriela Peste, Nela Bibire, Mihai Apostu, Aurel Vlase, Corneliu Oniscu].
An original liquid chromatography-tandem mass spectrometry (LC-MS-MS) method coupled to online extraction has been developed for cyanide determination in blood. A method involving fluorimetric detection after naphthalene-2,3-dicarboxyaldehyde (NDA) complexation by taurine in the presence of cyanide was previously described. Its performance was limited because of the absence of an internal standard (IS). Using cyanide isotope 13C15N as IS allowed quantification in MS-MS. After the addition of 13C15N, 25 µL of blood were diluted in water and deproteinized with methanol. Following derivatization with NDA and taurine for 10 min at 4°C, 100 µL was injected into the online LC-MS-MS system. An Oasis HLB was used as an extraction column, and a C18 Atlantis was the analytical column. The chromatographic cycle was performed with an ammonium formate (20 mM, pH 2.8) (solvent A) and acetonitrile/solvent A (90:10, v/v) gradient in 6 min. Detection was performed in negative electrospray ionization mode ...
TY - JOUR. T1 - Bioanalysis of 6-diazo-5-oxo-l-norleucine in plasma and brain by ultra-performance liquid chromatography mass spectrometry. AU - Alt, Jesse. AU - Potter, Michelle C.. AU - Rojas, Camilo. AU - Slusher, Barbara. PY - 2015/4/1. Y1 - 2015/4/1. N2 - Glutamine is an abundant amino acid that plays pivotal roles in cell growth, cell metabolism, and neurotransmission. Dysregulation of glutamine-using pathways has been associated with pathological conditions such as cancer and neurodegenerative diseases. 6-Diazo-5-oxo-l-norleucine (DON) is a reactive glutamine analog that inhibits enzymes affecting glutamine metabolism such as glutaminase, 2-N-amidotransferase, l-asparaginase, and several enzymes involved in pyrimidine and purine de novo synthesis. As a result, DON is actively used in preclinical models of cancer and neurodegenerative disease. Moreover, there have been several clinical trials using DON to treat a variety of cancers. Considerations of dose and exposure are especially ...
GE AKTA fast protein liquid chromatography system is an eagle-i resource of type Fast protein liquid chromatography instrument at Universidad Central del Caribe.
Liquid Chromatography / Tandem Mass Spectrometry (LS/MS/MS). Liquid chromatography/tandem mass spectrometry provides identification of analytes of interest within a mixture based on retention time and characteristic parent/daughter ion fragmentation patterns, which provides the compounds unique molecular fingerprint. When liquid chromatography is suitable for separation of compounds, LC/MS/MS can provide significantly greater sensitivity than the corresponding gas chromatography/mass spectrometry (i.e., GC/MS). KorvaLabs employs LC/MS/MS for the identification of substances in "white powders" - such as in the case of certification of dietary supplements - and for certain compounds in urine where GC/MS is not sufficient.. Gas Chromatography / Mass Spectrometry (GC/MS). Like LC/MS, the related gas chromatography/mass spectrometry (i.e., GC/MS)provides identification based on retention time and ion fragmentation patterns; however, GC/MS… KorvaLabs uses GC/MS for the detection of most banned ...
Steuer, Andrea E; Poetzsch, Michael; Stock, Lorena; Eisenbeiss, Lisa; Schmid, Yasmin; Liechti, Matthias E; Kraemer, Thomas (2017). Development and validation of an ultra-fast and sensitive microflow liquid chromatography-tandem mass spectrometry (MFLC-MS/MS) method for quantification of LSD and its metabolites in plasma and application to a controlled LSD administration study in huma. Drug Testing and Analysis, 9(5):788-797. ...
University of Leicester researchers writing in the journal Chemical Research in Toxicology say they have found convincing evidence that cannabis smoke damages DNA and it could potentially increase the risk of cancer development in humans.Using a newly developed highly sensitive liquid chromatography-tandem mass spectrometry method, the University
Disease-specific compounds (biomarkers) are analyzed in clinical laboratories to assist with diagnosing diseases. This thesis describes development and validation of liquid chromatography tandem mass spectrometry (LC-MS/MS) based tests for diagnosing a diverse group of endocrine and metabolic diseases. The analytical methods used on-line and off-line sample extraction and analytical derivatization as means of enhancing the analytical sensitivity, specificity and clinical utility. All developed methods were extensively validated and reference intervals for the biomarker concentrations were established in blood samples of healthy adults and children. Advantages of the LC-MS/MS as an analytical technique include possibility of simultaneous measurement of multiple analytes and ability of confirming their identity. In this thesis we proposed and evaluated approaches for the assessment of the specificity of analysis in the methods that use tandem mass spectrometry detection. To enhance throughput of ...
Abstract To support therapeutic drug monitoring of patients with cancer, a fast and accurate method for simultaneous quantification of the registered anticancer drugs afatinib, axitinib, ceritinib, crizotinib, dabrafenib, enzalutamide, regorafenib and trametinib in human plasma using liquid chromatography tandem mass spectrometry was developed and...
In this study, we developed the stable isotope dilution hydrophilic interaction liquid chromatography with tandem mass spectrometry (HILIC-MS/MS) technique for the accurate, reasonable and simultaneous quantification of glutamic acid (Glu), glutamine (Gln), pyroglutamic acid (pGlu), γ-aminobutyric acid (GABA) and theanine in mouse brain tissues. The quantification of these analytes was accomplished using stable isotope internal standards and the HILIC separating mode to fully correct the intramolecular cyclization during the electrospray ionization. It was shown that linear calibrations were available with high coefficients of correlation (r(2) | 0.999, range from 10 pmol/mL to 50 mol/mL). For application of the theanine intake, the determination of Glu, Gln, pGlu, GABA and theanine in the hippocampus and central cortex tissues was performed based on our developed method. In the region of the hippocampus, the concentration levels of Glu and pGlu were significantly reduced during reality-based theanine
A polyacrylamide (PAAm)-modified monolithic silica capillary column of increased phase ratio, 200T-PAAm, for hydrophilic interaction liquid chromatography (HILIC) was prepared. The column showed high separation efficiency, with a theoretical plate height H = 7â€"20 μm at a linear velocity, u = 1â€"7 mm/s. From a kinetic plot analysis, it was expected that the monolithic column could provide three times faster separation than particle-packed HILIC columns under a pressure limit at 20 MPa. HILIC coupled with electrospray ionization (ESI)â€"mass spectrometry (HILIC-ESI-MS) using the 200T-PAAm column was employed for the analysis of underivatized carbohydrates to achieve fast and efficient separations of mixtures containing mono-, di-, and trisaccharides within 5 min. Under single MS full scan mode, 200 pg of oligosaccharides was detected by the system. The limit of detection (LOD) of the LC-ESI-MS/MS system was determined using selected reaction monitoring (SRM) to be as low as 3.2 ...
1,2-Dehydro-N-acetyldopamine (dehydro NADA) and its derivatives have been identified as important cuticular sclerotizing precursors responsible for the hardening of the exoskeleton of soft-bodied insects. In addition, these compounds may serve as precursors in the biosynthesis of the large number of bioactive compounds present in the exoskeleton of marine invertebrates. In this work the products of non-enzymatic oxidation of 1,2-dehydro N-acyldopamine were examined using reversed-phase high performance liquid chromatography/electrospray/tandem mass spectrometry (RP-HPLC/ESI/MS-MS). In addition, the role of tyrosinase-catalyzed oxidation of dehydro-N-acetyldopamine in the cross-linking of cuticle proteins was studied by examining two thiol-containing nucleophiles and a model peptide using RP- HPLC/ESI/MS-MS. Finally, the tyrosinase-catalyzed oxidative cyclization and polymerization of N-acetyl-1,2-dehydro Dopa was examined as a possible biosynthetic pathway for forming bioactive compounds called
Learn about Agilent׷ liquid chromatography/mass spectrometry (LC/MS). Agilent LC/MS enables a wide array of applications by combining sample preparation, liquid chromatography (LC), mass spectrometry (MS), and dedicated software tools like compound databases and libraries.
Journal of Chemistry is a peer-reviewed, Open Access journal that publishes original research articles as well as review articles on all aspects of fundamental and applied chemistry.
Manufacturer of Liquid Chromatography Mass Spectrometry - LCMS QQQ 6460 Mass Spectrometer, CAH Mass Solution offered by Trivitron Healthcare Pvt. Ltd., Chennai, Tamil Nadu.
Many direct immunoassays in use today for testosterone analysis are little better than a guess at the low levels that are sometimes required.  This has led many clinical societies to adv
Lai, Yongquan, "Development and application of liquid chromatography mass spectrometry methods for the analysis and toxicity study of polybrominated diphenyl ether metabolites" (2013). Restricted Access Theses and Dissertations. 1437 ...
This contribution relates to the assessment of gradient-elution parameters in capillary liquid chromatography affecting the peak widths in the reversed-phase separation of peptides and intact proteins. Gradient separations were performed using both a poly(sytrene-co-divinylbenzene) monolithic column and a microparticulate fused-core column (silica C18, 2.7 mu m). The applicability of the conventional linear (LSS) and non-linear solvent-strength model (Neue-Kuss) were investigated to describe the retention behaviour of the compounds as a function of the mobile-phase composition. This was performed by using a wide range of gradient conditions, including different gradient slopes (beta, ranging from 0.05 to 0.65 min(-1)) and mobile-phase compositions (Delta phi, i.e. gradient span). Although the LSS-model provided accurate retention time predictions (,1.3% deviation) of scouting runs with more conventional gradient slopes, the prediction of high-speed separations with a high degree of accuracy ...
Results .Quantifying multi-omics data under circadian cycles . To investigate global phosphorylation in flies, we conducted quantitative proteomics and phosphoproteomics using the Tandem Mass Tag (TMT) labeling and liquid chromatography-tandem mass spectrometry (LC-MS/MS) on WT and per 0fly heads collected at 3?h intervals on 2 days under constant darkness (DD) condition (Fig.? 1a ). Altogether we identified 61,460 non-phosphorylated peptides and 12,465 phosphopeptides from 32 samples. The majority of the peptides (35,280; 57.40%) and phosphopeptides (8193; 65.73%) could be matched with ≥2 spectral counts, whereas the average spectral counts were 2.5 and 4.4 for all peptides and phosphopeptides, respectively (Fig.? 1b ). We next mapped non-phosphorylated peptides to their corresponding protein sequences, and obtained 5998 and 6034 proteins in WT and per 0flies, respectively (Supplementary Data? 1 ). Only 14.87% (912) of 6134 quantified proteins were assigned with one matched peptide, with an ...
J Chromatogr B Analyt Technol Biomed Life Sci. 2007 Sep 15;857(1):1-8. Epub 2007 Jun 29. Comparative Study; Evaluation Studies; Research Support, N.I.H., Extramural
Plant polysaccharides constitute arguably the most complex family of biomacromolecules in terms of the stereochemistry and regiochemistry of their intramolecular linkages. The chemical modification of such polysaccharides introduces an additional level of complexity for structural determinations. We have developed an integrated analytical procedure combining selective enzymatic hydrolysis, hydrophilic interaction liquid chromatography (HILIC), and mass spectrometry (MS) to describe the substitution pattern of xyloglucan (XyG) and its chemo-enzymatic derivatives (cationic, anionic, and benzyl aminated). Enzymatic hydrolysis of XyG derivatives by a xyloglucan-specific endoglucanase (XEG) generates oligosaccharides amenable for mass spectrometric identification with distinct structures, based on enzymatic substrate recognition and hydrolytic pattern. Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-ToF-MS) and electrospray ionisation mass spectrometry (ESI-MS) ...
The recent explosion in available genomic and protein sequence information is providing a sequence infrastructure for the emerging field of proteomics. A major aspect of many proteomics strategies is the identification of proteins using an analytical "fingerprint" that can be used to search a sequence database. One common "fingerprint" is the tandem mass (MS/MS) spectrum of a peptide. Thus, an MS/MS spectrum can be algorithmically compared with predicted peptide spectra from a sequence database to identify the respective protein (1, 2). The digestion of intact protein mixtures followed by the direct analysis of the resulting peptides by capillary liquid chromatography-MS/MS has facilitated "shotgun" identification of protein mixtures without the need for prior sample fractionation (3). Combined with the recent development of capillary multidimensional liquid chromatography [multidimensional protein identification technology (MudPIT)], this approach is now capable of characterizing proteins ...
Trypanosomatids express complex glycoproteins and glycolipids that are often essential to their viability and virulence. In these parasites, sugar nucleotides are the sugar donors for protein and lipid glycosylation. But there had been no information on which sugar nucleotides are present in these parasites, and what their cellular concentrations might be. Daniel C. Turnock and Michael A.J. Ferguson of the University of Dundee, Scotland, United Kingdom, developed a new liquid chromatography/tandem mass spectrometry method to sensitively and selectively identify and measure sugar nucleotides in cell extracts.
Data Advisory. The purpose of this analytical note is to inform researchers that serum 25-hydroxyvitamin D (25(OH)D) data from NHANES III (1988-1994) and NHANES 2001-2006 have been converted by using regression to equivalent 25(OH)D measurements from a standardized liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. The LC-MS/MS method was used in the analysis of the newly released NHANES 2007-2010 25(OH)D data. This standardization was done so that researchers could use 25(OH)D data that are equivalent to 25(OH)D measurements assayed with a LC-MS/MS method that is traceable to the NIST reference materials. The LC-MS/MS-equivalent data for NHANES III (1988-1994) and NHANES 2001-2006 are needed to compare with 25(OH)D data from NHANES 2007-2010, which were obtained using the LC-MS/MS method. This analytical note replaces the previous analytical note entitled "Revised Analytical Note for NHANES 2000-2006 and NHANES III (1988-1994) 25-Hydroxyvitamin D Analysis (Revised November ...
Hydrophilic interaction liquid chromatography (HILIC), although not a new technique, has enjoyed a recent renaissance with the introduction of robust and reproducible stationary phases. It is consequently finding application in metabolomics studies, which have traditionally relied on the stability of reversed phases (RPs), since the biofluids analyzed are predominantly aqueous and thus contain many polar analytes. HILICs retention of those polar compounds and use of solvents readily compatible with mass spectrometry have seen its increasing adoption in studies of complex aqueous metabolomes. This review describes the stationary phases and their features. surveys HILIC-LC-MSs role in metabolomics experiments, discusses approaches to data extraction and analysis including multivariate analysis, and reviews the literature on HILIC MS applications in metabolomics. (C) 2009 Wiley Periodicals, Inc., Mass Spec Rev 29:671-684, 2010 ...
In the article below, Jie Ding, associate director of development and validation at the PPD® Laboratories GMP lab, discusses liquid chromatography-mass spectrometry in drug discovery and development.. In a drug stability program, high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection remains the most common and cost-effective methodology. Even so, UV detection has its own limitations, including poor sensitivity for non-UV absorbing compounds and lack of specificity. These shortcomings in turn have motivated scientists to pursue other alternatives. Mass spectrometry detection is such a candidate. Mass spectrometry (MS) is a detection method that measures the mass-to-charge ratio (m/z) of a compound. Compared to UV detection, MS offers higher sensitivity, better detection limits, and the ability to provide additional molecular weight information-making it an "information rich" detection method.. Over the last two decades, MS has become an important analytical tool to ...
Definition : High-pressure packed-column liquid chromatography systems in which the packing of the column is made of microparticulate silica gel. The functional groups of the stationary phase may be polar relative to those of the mobile phase (i.e., normal bonded-phase chromatography) or, more usually, nonpolar (i.e., reverse bonded-phase chromatography).. Entry Terms : "Reverse-Phase Liquid Chromatography Systems" , "Normal-Phase Liquid Chromatography Systems" , "Bonded-Phase Liquid Chromatography Systems". UMDC code : 18278 ...
Paul A. Rudnick, Karl R. Clauser, Lisa E. Kilpatrick, Dmitrii V. Tchekhovskoi, Pedatsur Neta, Nikša Blonder, Dean D. Billheimer, Ronald K. Blackman, David M. Bunk, Helene L. Cardasis, Amy-Joan L. Ham, Jacob D. Jaffe, Christopher R. Kinsinger, Mehdi Mesri, Thomas A. Neubert, Birgit Schilling, David L. Tabb, Tony J. Tegeler, Lorenzo Vega-Montoto, Asokan Mulayath Variyath, Mu Wang, Pei Wang, Jeffrey R. Whiteaker, Lisa J. Zimmerman, Steven A. Carr, Susan J. Fisher, Bradford W. Gibson, Amanda G. Paulovich, Fred E. Regnier, Henry Rodriguez, Cliff Spiegelman, Paul Tempst, Daniel C. Liebler and Stephen E. Stein ...
Sathananthan M, Sathananthan A, Scheithauer BW, Giannini C, Meyer FB, Atkinson JL, Erickson D. Sellar meningiomas: an endocrinologic perspective. Pituitary. 2012 May 27.. Smushkin G, Sathananthan M, Sathananthan A, Dalla Man C, Micheletto F, Zinsmeister AR, Cobelli C, Vella A. Diabetes-associated common genetic variation and its association with GLP-1 concentrations and response to exogenous GLP-1. Diabetes. 2012 May;61(5):1082-9. Smushkin G, Sathananthan A, Man CD, Zinsmeister AR, Camilleri M, Cobelli C, Rizza RA, Vella A. Defects in GLP-1 response to an oral challenge do not play a significant role in the pathogenesis of prediabetes. J Clin Endocrinol Metab. 2012 Feb;97(2):589-98.. Erickson D, Singh RJ, Sathananthan A, Vella A, Bryant SC. Late-night salivary cortisol for diagnosis of Cushings syndrome by liquid chromatography/tandem mass spectrometry assay. Clin Endocrinol (Oxf). 2012 Apr;76(4):467-72.. Sathananthan A, Dalla Man C, Zinsmeister AR, Camilleri M, Rodeheffer RJ, Toffolo G, ...
Analysis of compounds present in complex matrices is always a challenge, which can be partly overcome by applying various sample preparation techniques prior to detection. Ideally, the extraction techniques should be as selective as possible, to minimize the concentration of interfering substances. In addition, results can be improved by efficient chromatographic separation of the sample components. The elimination of interfering substances is especially important when utilizing mass spectrometry (MS) as a detection technique since they influence the ionization yields. It is also important to optimize ionization methods in order to minimize detection limits.. In the work this thesis is based upon, selective solid phase extraction (SPE) materials, a restricted access material (RAM) and graphitized carbon black (GCB) were employed for clean up and/or pre-concentration of analytes in plasma, urine and agricultural drainage water prior to liquid chromatography/mass spectrometry (LC/MS). Two SPE ...
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TY - CHAP. T1 - Probing carbonyl metabolome by liquid chromatography-mass spectrometry (LC-MS). AU - Soboleva, Alena. AU - Kysil, Elana. AU - Frolova, Nadezhda AU - Shumilina, Julia. AU - Bureiko, Kseniia. AU - Paudel, Gagan. AU - Grishina, Tatiana. AU - Karonova, Tatiana. AU - Birkemeyer, Claudia AU - Wessjohann, Ludger A. AU - Frolov, Andrej. PY - 2020/4. Y1 - 2020/4. KW - 7- (diethylamino) -coumarin-3-carbohydrazide. KW - blood plasma. KW - mass-spectrometry. KW - oxidative stress. KW - plant extract. KW - reactive carbonyl compounds. M3 - Other chapter contribution. SP - 88. BT - DGMS 2020. ER - ...
For routine analysis or cutting-edge research, rent, lease or finance your next Agilent InfinityLab LC Liquid Chromatography System from Quantum Analytics.
Background: Red blood cells (RBCs) represent a storage pool for folate. In contrast to plasma, RBC folate can appear in different biochemical isoforms. So far, only the methylenetetrahydrofolate reductase (MTHFR) 677 TT genotype has been identified as a determinant of RBC folate vitamer distribution. Objective: The purpose of this study is to identify clinical and biochemical determinants of RBC folate vitamer distribution in healthy subjects. Design: In an observational study, 109 subjects, aged 18 to 65 years, were studied. Red blood cell folate vitamers were analyzed using a liquid chromatography-tandem mass spectrometry method. Other variables recorded included vitamin B2, B6 and B12 status, homocysteine, plasma and RBC S-adenosylhomocysteine and S-adenosylmethionine, renal function and the MTHFR C677T polymorphism. Results: The MTHFR C677T genotype was the dominant determinant of nonmethylfolate accumulation. The median (range) nonmethylfolate/total folate ratio was 0.58% (0-12.2%) in the ...
Methods This analysis was conducted among controls from a population-based case-control study of breast cancer among women of Chinese, Japanese and Filipino ancestry, aged 20-55 years, and living in San Francisco-Oakland (CA), Los Angeles (CA) and Oahu (HI). Of 966 controls, we included the 571 (59%) women who donated a 12-hour urine and had not been pregnant or lactating or used exogenous hormones in the last 6 months. At urine collection, 168 women were postmenopausal, 233 were pre-menopausal in mid-luteal phase, and 170 were in other categories. Fifteen EM were measured simultaneously with a highly sensitive and reproducible liquid chromatography-tandem mass spectrometry method. Participants had been queried about their usual adult frequency of intake of tofu and other selected soy foods. Robust regression was used to model the associations of soy intake (in tertiles) with EM measures. Models were adjusted for age, ethnicity, body mass index (BMI), and birthplace (Asia/West). ...
Proteomic analysis was performed using a whole-cell lysate made from BT474 ductal breast carcinoma cells in the laboratory of Prof. Kian Kani, University of Southern California, Los Angeles. Briefly, BT474 cells were lysed in PBS, 1% OG, with a full complement of protease and phosphatase inhibitors. The cells were then subjected to reduction (5 mM DTT) and alkylation (50 mM IAA) in a final concentration of 6 M guanidine-HCl in PBS/OG. Protein identification was carried out using liquid chromatography/tandem mass spectrometry (LC/MS-MS) in a data-dependent mode. To reduce sample complexity, an initial RP-HPLC protein fractionation was performed by injecting 2 mg of protein lysate (in 3M guanidine hydrochloride in PBS) and collecting 1-ml fractions every 30 sec, for a total of 19 separate fractions, which were then frozen, and dried with a SpeedVac. Each fraction was resuspended in 100 mM ammonium bicarbonate buffer, pH 8.0 containing 1 M urea + 1% acetonitrile (ACN), for a total volume of 200 ...
Nucleoside analogs are an important class of drugs in anticancer and antiviral therapy. The compounds are, however, only active after intracellular conversion to their mono-, di- and triphosphate nucleotide form. In this thesis the development of sensitive liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) assays to quantitate nucleoside and ... read more nucleotide analogs in cells is described. These assays were then applied to preclinical and clinical studies. Synthesis of nucleotide analogs In chapter 1 the synthesis of small amounts of nucleotide analogs from nucleoside analogs is described. These nucleotide analogs were required as reference and internal standards in quantitative analytical assays. Bioanalysis of intracellular nucleoside and nucleotide analogs First, a literature overview of liquid chromatography - mass spectrometry (LC-MS) methods for the quantitative determination of nucleotide analogs in cells is given (chapter 2.1). The development and validation of ...
The highly versatile Liquid Chromatography-Mass Spectrometry instrument illustrated here can separate and quantify analytes as diverse as vitamins and minerals, mycotoxins and illegal dyes. Read more...
A procedure based on liquid chromatography/tandem mass spectrometry (LC/MS/MS) is described for the determination of nicotine and its principal metabolites cotinine, trans-3-hydroxycotinine and cotinine-N-oxide, caffeine and arecoline in breast milk, using N-ethylnorcotinine as internal standard. Li …
TY - JOUR. T1 - Quantification of sunitinib in human plasma by high-performance liquid chromatography-tandem mass spectrometry. AU - Minkin, Patton. AU - Zhao, Ming. AU - Chen, Zhaoyuan. AU - Ouwerkerk, Jan. AU - Gelderblom, Hans. AU - Baker, Sharyn D.. PY - 2008/10/15. Y1 - 2008/10/15. N2 - A rapid, sensitive and specific method was developed and validated using LC/MS/MS for determination of sunitinib in human plasma. Sample preparation involved a liquid-liquid extraction by the addition of 0.2 mL of plasma with 4.0 mL tert-butyl-methyl-ether extraction solution containing 25 ng/mL of the internal standard clozapine. Separation of compounds was achieved on a C18 (50 mm × 2.1 mm i.d., 3.5 μm) analytical column using a mobile phase consisting of acetonitrile/H20 (65:35, v/v) containing 0.1% formic acid and isocratic flow at 0.150 mL/min for 3 min. The analytes were monitored by tandem-mass spectrometry with electrospray positive ionization. Linear calibration curves in human plasma were ...
Feijoa fruit is becoming increasingly popular, yet limited studies have focused on the antioxidant capacity and phenolic profiling of its extracts. In this research, optimization of phenolic extraction from feijoa flesh, peel, and whole fruit from four New Zealand grown cultivars was conducted using orthogonal design. Antioxidant activities of the extracts were assessed, followed by phenolic profiling by a validated liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method. For feijoa flesh and whole fruit, the extraction was optimized using 70% ethanol, material to solvent ratio of 1:30, at extraction temperature of 50 °C for 30 min. For feijoa peel, extraction at 50 °C for 60 min using 50% ethanol with a material to solvent ratio of 1:30 were the optimized conditions. Results showed feijoa peel had higher total phenolic content (TPC) and antioxidant activities than the flesh and whole fruit. Overall, the Unique cultivar had a relatively higher TPC and ...
The Catalonian Antidoping Laboratory is one of the laboratories accredited by the World Anti-doping Agency (WADA-AMA) to perform doping controls in athletes. The laboratory received its first accreditation in 1985 by the International Olympic Committee. In 1994 the laboratory was also accredited by the Association of Official Racing Chemists (AORC) to undertake doping controls in animals. In order to develop its activities and comply with the WADA and AORC directives, since 2000 the laboratory has the ISO 17025 accreditation from the national accreditation body (ENAC No. 239 / LE485).. The laboratory is equipped with a wide range of chromatography-mass spectrometry instruments: liquid chromatography-tandem mass spectrometry (triple quadrupole, QTOF), gas chromatography-mass spectrometry, gas chromatography-tandem mass spectrometry (triple quadrupole), and gas chromatography-isotope ratio mass spectrometry. The laboratory has also equipment for applying immunological and electrophoresis ...
Amphetamine, methamphetamine, illicit designer phenethylamines (MDA, MDEA, MDMA, MBDB, and BDMPEA), and other phenethylamines (benzyl-1-phenylethylamine, cathinone, ephedrine, fenfluramine, norfenfluramine, phentermine, 1-phenylethylamine, phenylpropanolamine, and propylhexedrine) were extracted from serum using a solid-phase extraction procedure. The extracts were examined with high-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry (LC-APCI-MS). The drugs were separated on ODS column in acetonitrile/50mM ammonium formate buffer (pH 3.0) (25:75) as a mobile phase. Full-scan mass spectra of drugs examined by means of APCI with collision-induced dissociation showed protonated molecular ions and fragments typical for particular drugs. LC-APCI-MS allowed an unequivocal differentiation of all drugs involved. The quantitation was performed using selected ion monitoring of protonated molecular ions and fragments of drugs involved and their deuterated ...
Bile acids (BAs) are important modulators of metabolic functions such as lipid, triglyceride and glucose homeostasis. Intrahepatic accumulation of BAs is known to cause liver injury in cholestatic conditions, where normal trans-hepatic BA flow is impaired due to pathological conditions or induced by toxic drugs. Therefore, it is important to understand the mechanisms of BA homeostasis regulation and to identify novel players and characterize their functions. The main goal of the present work was to investigate the impact of altered hepatic glucocorticoid activation by the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) on BA homeostasis and to unravel the mechanisms of adaptations in a scenario of impaired 11β-HSD1 function. In order to achieve this goal, we developed and validated an ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for the quantification of a total of 24 BAs, including 11 unconjugated, 6 glycine-conjugated and 7 ...
Phytoestrogen exposure correlation with plasma estradiol in postmenopausal women in European Prospective Investigation of Cancer and Nutrition-Norfolk may involve diet-gene interactions Cross-sectional studies investigating the relationship between phytoestrogens in diet, urine, or blood with plasma estradiol and sex hormone binding globulin (SHBG) have been inconclusive. We investigated the relationship among phytoestrogen exposure, polymorphisms in the ESR1, COMT, CYP19, and SHBG genes, and plasma estradiol and SHBG levels in 125 free-living postmenopausal women taking part in a cohort study (European Prospective Investigation of Cancer and Nutrition-Norfolk) using three different markers: dietary, urinary, and serum phytoestrogens. Phytoestrogen levels (daidzein, genistein, glycitein, O-desmethylangolensin, equol, enterodiol, and enterolactone) in spot urine and serum were analyzed by gas chromatography/mass spectrometry and liquid chromatography/tandem mass spectrometry, respectively. Plasma ...
An liquid chromatography-mass spectrometry method using electrospray ionization in negative ion mode coupled with a hybrid quadrupole linear ion trap and Fourier transform ion cyclotron resonance (FTICR) mass spectrometer was applied to characterize of intact glucosinolates (GLSs) in crude sample extracts of wild bud flowers of Capparis spinosa (Capparis species, family Capparaceae). Structural information of GLSs was obtained upon precursor ions isolation within the FTICR trapping cell and subsequent fragmentation induced by infrared multiphoton dissociation (IRMPD). Such a fragmentation was found very useful in terms of chemical identification of all precursor ions [M-H]- including sulfur-rich GLSs reported here for the first time. Along with most common GLSs already found in capers such as glucocapparin, isopropyl/n-propyl- GLS, mercapto-glucocapparin, and two indolic GLS, i.e., 4-hydroxyglucobrassicin and glucobrassicin, the occurrence of the uncommon glycinyl-glucocapparin as well as two ...
Journal of Liquid Chromatography & Related Technologies. 20 (16-17): 2857-2872. doi:10.1080/10826079708005597.. ... Particles that move further away from the wall reach higher positions in the parabolic velocity profile of the liquid flowing ...
In liquid chromatography, the eluent is the liquid solvent; in gas chromatography, it is the carrier gas.[1] ... In a liquid chromatography experiment, for example, an analyte is generally adsorbed, or "bound to", an adsorbent in a liquid ... For instance, a mixture of amino acids may be separated by ion-exchange chromatography. Under a particular set of conditions, ... Brown, Phillis (2001). Advances in chromatography. CRC Press. p. 36. ISBN 0-8247-0509-2. .. ...
Labdon JE, Nieves E, Schubart UK (February 1992). "Analysis of phosphoprotein p19 by liquid chromatography/mass spectrometry. ...
Analytical techniques, in general, involve gas or liquid chromatography.[33][34][35] ...
By choosing porous graphitic carbon as a stationary phase for liquid chromatography, even non derivatized glycans can be ... Fractionated glycans from high-performance liquid chromatography (HPLC) instruments can be further analyzed by MALDI-TOF-MS(MS ... N-glycans from glycoproteins are analyzed routinely by high-performance-liquid-chromatography (reversed phase, normal phase and ... Ruhaak LR, Deelder AM, Wuhrer M (May 2009). "Oligosaccharide analysis by graphitized carbon liquid chromatography-mass ...
Similar to gas chromatography MS (GC-MS), liquid chromatography-mass spectrometry (LC/MS or LC-MS) separates compounds ... The duty cycle of IMS is short relative to liquid chromatography or gas chromatography separations and can thus be coupled to ... Covey TR, Lee ED, Henion JD (October 1986). "High-speed liquid chromatography/tandem mass spectrometry for the determination of ... Covey TR, Crowther JB, Dewey EA, Henion JD (February 1985). "Thermospray liquid chromatography/mass spectrometry determination ...
"Liquid chromatography-mass spectrometry: potential in forensic and clinical toxicology". Journal of Chromatography B. 733 (1-2 ... chromatography, etc.), the size boundaries that distinguish peptides from polypeptides and proteins are not absolute: long ...
"Screening for N-glycosylated proteins by liquid chromatography mass spectrometry". Proteomics. 4 (2): 454-65. doi:10.1002/pmic. ...
... gas chromatography-infrared spectroscopy, liquid chromatography-mass spectrometry, liquid chromatography-NMR spectroscopy. ... Holt, R. M.; Newman, M. J.; Pullen, F. S.; Richards, D. S.; Swanson, A. G. (1997). "High-performance Liquid Chromatography/NMR ... Chromatography, electrophoresis and Field Flow Fractionation are representative of this field. Hybrid techniques[edit]. ... Bartle, Keith D.; Myers, Peter (2002). "History of gas chromatography". TrAC Trends in Analytical Chemistry. 21 (9-10): 547. ...
"Analysis of benzodiazepine derivative mixture by gas-liquid chromatography" (PDF). Medicina (Kaunas, Lithuania) (in Lithuanian ... "Determination of benzodiazepine derivatives mixture by high performance liquid chromatography". Medicina (Kaunas, Lithuania). ... Journal of Chromatography A. 1216 (15): 3192-8. doi:10.1016/j.chroma.2009.02.001. ISSN 0021-9673. PMID 19233363. Schubert, B; ...
Niessen, Wilfried (2006). Liquid Chromatography Mass spectrometry. 6000 Broken Sound Parkway NW, Suite 300, Boca Raton, FL ... The analyte in solution is introduced from a direct inlet probe or a liquid chromatography (LC) eluate into a pneumatic ... The sensitivity of APCI combined with the sensitivity and specificity of LC/MS and liquid chromatography-tandem mass ... Thomson, Bruce A. (1998-03-01). "Atmospheric pressure ionization and liquid chromatography/mass spectrometry-together at last ...
During a sabbatical with Prof JC Giddings in Utah in 1964, Knox was introduced to column liquid chromatography. Back home in ... In the 1970s Knox and his Edinburgh research group invented new micro-particulate packing materials for liquid chromatography, ... Berthod, Alain (1989). "On the Use of the Knox Equation". Journal of Liquid Chromatography. 12 (7): 1187-1201. Retrieved 15 ... now used commonly to describe the spreading of a solute into bands in liquid chromatography. John Knox was elected a Fellow of ...
Niessen, Wilfried M. A. (1999). Liquid chromatography-mass spectrometry. 79. CRC Press. p. 84. ISBN 978-0-8247-1936-4. "Exhaust ...
Lauback, Ronald; Lauback, RG (1982). "High-Pressure Liquid Chromatography". Journal of Liquid Chromatography & Related ... Lauback, Ronald (1984). "High-Performance Liquid Chromatographic". Journal of Liquid Chromatography & Related Technologies. 7: ... Journal of Liquid Chromatography & Related Technologies, Volume 5, Issue 7 1982). "Specific High-Performance Liquid ... examples: "High-Pressure Liquid Chromatography Assay for Dane Salt Potassium(-)-N-(1-Methoxycarbonylpropene-2yl)-p- ...
Journal of Liquid Chromatography. 18 (14): 2801-2812. doi:10.1080/10826079508009325. Bastian G, Urien S, Brée F, Jolliet P, ... "Determination of 4-Hydroxytertatolol Stereoisomers in Rat and Human Urine by High-Performance Liquid Chromatography". ...
Wouten, J.; Verhecken, A. (1991). "High-performance liquid chromatography of blue and purple indigoid natural dyes". Journal of ...
... and coupling with liquid chromatography". Journal of Chromatography A. 856 (1-2): 3-54. doi:10.1016/S0021-9673(99)00832-8. ISSN ... SPE and chromatography[edit]. SPE is not a method of chromatography, except in the broadest, simplest sense. It is an ... Solid-phase extraction (SPE) is an extractive technique by which compounds that are dissolved or suspended in a liquid mixture ... SPE uses the affinity of solutes dissolved or suspended in a liquid (known as the mobile phase) for a solid through which the ...
Liquid chromatography fractions are more difficult because of the solvent present. One notable exception is to measure chain ... FTIR as detector in chromatography[edit]. The speed of FTIR allows spectra to be obtained from compounds as they are separated ... Liquid nitrogen cooled mercury cadmium telluride (MCT) detectors are the most widely used in the mid-IR. With these detectors ... Very sensitive liquid-helium-cooled silicon or germanium bolometers are used in the far-IR where both sources and beamsplitters ...
It transfers ions from the liquid phase to the gas phase for analysis. It is particularly useful in liquid chromatography-mass ... Gelpí E (1995). "Biomedical and biochemical applications of liquid chromatography-mass spectrometry". Journal of Chromatography ... Thermospray was originally developed for coupling liquid chromatography to mass spectrometry (LC-MS). Thermospray is the ... Vestal, Marvin L. (1990). "[5] Liquid chromatography-mass spectrometry". 193: 107-130. doi:10.1016/0076-6879(90)93413-F. ISSN ...
Gladney, HM; Dowden, BF; Swalen, JD (1969). "Computer-Assisted Gas-Liquid Chromatography". Anal. Chem. 41 (7): 883-888. doi: ... An alternative but equivalent form of the EMG distribution is used for description of peak shape in chromatography. This is as ... Laplace-normal distribution Grushka, Eli (1972). "Characterization of Exponentially Modified Gaussian Peaks in Chromatography ...
These plasma samples were then analyzed using liquid chromatography-tandem mass spectrometry. The results showed that ...
Journal of Liquid Chromatography & Related Technologies. 30: 2717-27. doi:10.1080/10826070701560629. Dulger B (2005). " ...
Journal of Liquid Chromatography & Related Technologies. 37 (3): 311-320. doi:10.1080/10826076.2012.745137. Kim EJ, Shin WH, ...
Testing of Optical Purity Applying 1-Acid-Glycoprotein Stationary Phase". Journal of Liquid Chromatography & Related ... 1996). "Validation of liquid chromatographic and gas chromatographic methods Applications to pharmacokinetics". Journal of ... on United States Pharmacopoeia XXVI assay ginsenosides in Asian and American ginseng by high-performance liquid chromatography ... Chromatography B. 686 (1): 3-10. doi:10.1016/S0378-4347(96)00088-6. Peptisyntha S.A. (2009). "Commercial scale production". ...
Journal of Liquid Chromatography & Related Technologies. 30 (18): 2717-27. doi:10.1080/10826070701560629. Marley G. (2010). ...
Analyses of raw seeds from eight different location in Japan by high-performance liquid chromatography showed concentrations of ... Journal of Liquid Chromatography & Related Technologies. 29: 605-616. doi:10.1080/10826070500531466. Fiehe K.; Arenz A.; Drewke ... Yoshimura T.; Udaka N.; Morita J.; Jinyu Z.; Sazaki K.; Kobayashi D.; Wada K. (2006). "High performance liquid chromatographic ... Journal of Chromatography A. 1216: 2002-2032. doi:10.1016/j.chroma.2009.01.013. PMID 19195661. Scott P.M.; Lau B.Y-P.; Lawrence ...
... simultaneous quantitation of four aminopyrine metabolites by high-performance liquid chromatography". Arch. Biochem. Biophys. ...
High performance liquid chromatography or high pressure liquid chromatography is a form of chromatography applying high ... Thirdly, proteins may be separated by polarity/hydrophobicity via high performance liquid chromatography or reversed-phase ... Regnier FE (October 1983). "High-performance liquid chromatography of biopolymers". Science. 222 (4621): 245-52. doi:10.1126/ ... The tendency of a given particle to move through the liquid because of this force is offset by the resistance the liquid exerts ...
A procedure based on liquid chromatography/tandem mass spectrometry (LC/MS/MS) is described for the determination of nicotine ... Liquid Chromatography/Electrospray Ionization Tandem Mass Spectrometry Assay for Determination of Nicotine and Metabolites, ... Liquid Chromatography/Electrospray Ionization Tandem Mass Spectrometry Assay for Determination of Nicotine and Metabolites, ... A procedure based on liquid chromatography/tandem mass spectrometry (LC/MS/MS) is described for the determination of nicotine ...
Mass Spectrometry, Liquid Chromatography, Supercritical Fluid Chromatography, Ion Mobility, POPs, Electrospray Ionization ... Analysis of hexafluoropropylene oxide-dimer acid (HFPO-DA) by liquid chromatography-mass spectrometry (LC-MS): Review of ... The following review describes existing liquid chromatography-mass spectrometry (LC-MS) methods used to analyse HFPO-DA, ... HFPO-DA, GenX, Negative polarity electrospray ionisation, Liquid chromatography, Mass spectrometry National Category Chemical ...
Chromatography: …at the microgram-to-milligram level and preparative-scale liquid chromatography at the tens-of-grams level ... In biotechnology, preparative-scale liquid chromatography is especially important for purification of proteins and peptide ... Other articles where Preparative-scale liquid chromatography is discussed: separation and purification: ... Preparative-scale liquid chromatography. chemistry. Learn about this topic in these articles:. chemical separation and ...
... liquid chromatography with samples at the microgram-to-milligram level and preparative-scale liquid chromatography at the tens- ... In biotechnology, preparative-scale liquid chromatography is especially important for purification of proteins and peptide ... Both analytical-scale liquid chromatography with samples at the microgram-to-milligram level and preparative-scale liquid ... Analytical-scale liquid chromatography. chemistry. THIS IS A DIRECTORY PAGE. Britannica does not currently have an article on ...
High-performance liquid chromatography (HPLC) has become a standard technique in the laboratory. The intent of this chapter is ... High-performance liquid chromatography (HPLC) has become a standard technique in the laboratory. The intent of this chapter is ... Stein S. (1982) High-Performance Liquid Chromatography. In: Lajtha A. (eds) Experimental Neurochemistry. Springer, Boston, MA. ... Jones, B. N., Pääbo, S., and Stein, S., 1981, J. Liquid Chromatogr. 4:565-586.CrossRefGoogle Scholar ...
... Liquid chromatography (LC) testing and analysis.. Intertek provides Liquid Chromatography (LC) ... Liquid chromatography allows for selective and highly sensitive detection of trace and molecular-species specific compounds. ... Liquid chromatography analytical techniques: *High Performance Liquid Chromatography [LC, HPLC] *Liquid Chromatography Mass ...
But the labor intensity of the procedure is now a thing of the past for researchers in the Oregon Health & Science University School of Medicine. The Proteomics Shared Resource, an unassuming but state-of-the-art lab on the fifth floor of OHSUs Medical Research Building, can process more than three times as many protein samples in half a day, and much of it can be done by one person.. ...
Introduction to Liquid Chromatography webinar. 2. An interactive Q&A session for Dr Polites Resolution in Liquid ... Liquid-liquid and liquid-solid extractions (LLE and LSE) * Static headspace extraction (SHE) * Solid phase extraction (SPE) * ... Introduction to Liquid Chromatography webinar.. 2. An interactive Q&A session for Dr Polites Resolution in Liquid ... Introduction to Liquid Chromatography webinar.. 2. An interactive Q&A session for Dr Polites Resolution in Liquid ...
For both gas chromatography and liquid chromatography, the most informative detection technique is to couple the chromatography ... The investigators present examples of liquid (LC) and gas (GC) chromatography profiles for different herbal products. Liquid ... In liquid chromatography, many compounds that are characteristic for plant materials, such as polyphenols, can be detected via ... Govindarajan R et al., High-Performance Liquid Chromatography (HPLC) as a Tool for Standardization of Complex Herbal Drugs. ...
Gas-liquid chromatography in diagnosis of pyogenic arthritis. Br Med J 1978; 2 :1402 ... Gas-liquid chromatography in diagnosis of pyogenic arthritis.. Br Med J 1978; 2 doi: https://doi.org/10.1136/bmj.2.6149.1402 ( ...
... is a useful tool for those learning about the technology of liquid chromatography (LC), with a focus on high-performance liquid ... The Beginners Guide to Liquid Chromatography, a 56-page paperback book, ... chromatography (HPLC). The Beginners Guide offers an uncomplicated look at LC/HPLC and includes clear and colorful diagrams to ...
U.S. Geological Survey (USGS) scientist using a high-performance liquid chromatography (HPLC) system to fractionate water ...
Buy Liquid Chromatography Analysis products including 176002534 - Beverage Analysis Kit, 186006006 - Beverage Analysis Mobile ... The 2017/18 Waters Quality Parts, Chromatography Columns and Supplies Catalog is available! Download or order your copy today. ... The 2017/18 Waters Quality Parts, Chromatography Columns and Supplies Catalog is available! Download or order your copy today. ... Ultra Performance Liquid Chromatography High Liquid Chromatography Performance Liquid Chromatography Liquid Chromatography ...
Woods Hole Oceanographic Institution is the worlds leading non-profit oceanographic research organization. Our mission is to explore and understand the ocean and to educate scientists, students, decision-makers, and the public ...
... and these solvent systems can be used in liquid-liquid separations and countercurrent chromatography. The wide... ... Ionic liquids can form biphasic solvent systems with many organic solvents and water, ... The comparison of ionic liquid-liquid chromatography, high-performance liquid-liquid chromatography, high-performance liquid ... as ionic liquid-liquid chromatography (ILLC).. 3.2 The Use of Ionic Liquids in Chromatography. The use ionic liquids in ...
The liquid chromatography device comprises a separation substrate defining an introduction channel between an entrance orifice ... The exit orifice of the liquid chromatography device may be homogeneously interfaced with the entrance orifice of the ... a liquid chromatography device and an electrosprayliquid chromatography system are disclosed. The electrospray device comprises ... 47 shows a liquid chromatography-electrospray system 600 comprising a liquid chromatography device 602 of the present invention ...
Get the latest liquid chromatography product news on Environmental XPRT, the worlds largest environmental industry marketplace ... liquid chromatography product News. Related terms for "liquid chromatography product ": chromatography news , chromatography ... PerkinElmer broadens liquid chromatography portfolio with new high performance platform and chromatography data system ... PerkinElmer expands chromatography offering with new liquid chromatography autosampler PerkinElmer Life and Analytical Sciences ...
Get the latest quaternary liquid chromatography news on Environmental XPRT, the worlds largest environmental industry ... "quaternary liquid chromatography ": chromatography news , liquid chromatography news , quaternary liquid chromatography system ... infinity quaternary liquid chromatography system news , infinity quaternary liquid chromatography news ... Agilent Technologies Introduces New Version of Intelligent System Emulation Technology for Liquid Chromatography Systems ...
This track contains a series of modules that cover general liquid chromatography (LC) topics and concepts. It covers the ... This track contains a series of modules that cover general liquid chromatography (LC) topics and concepts. It covers the ... The 2017/18 Waters Quality Parts, Chromatography Columns and Supplies Catalog is available! Download or order your copy today. ... The 2017/18 Waters Quality Parts, Chromatography Columns and Supplies Catalog is available! Download or order your copy today. ...
Preparative Liquid Chromatography (H. Colin).. Process High Performance Liquid Chromatography (W. Skea).. Precision in HPLC (E ... Carbon in Liquid Chromatography (J. Knox & B. Kaur).. Organic Polymeric Stationary Phases (D. Pietrzyk).. Size-Exclusion Liquid ... The Theory of the Dynamics of Liquid Chromatography (S. Weber & P. Carr).. Mechanism of Solute Retention in Chromatography (R. ... High-Speed Liquid Chromatography (R. Simpson).. A Theoretical Approach to Derivatizations for HPLC (I. Krull, et al.).. ...
Standard linear filters are not effective for reducing noise in liquid chromatography-mass spectrometry (LC-MS) data because ... spiked noise is reduced in chromatography-mass spectrometry data by applying a nonlinear filter such as a moving median filter ... In liquid chromatography-mass spectrometry (LC-MS) or gas chromatography-mass spectrometry (GC-MS) data, the noise intensity is ... a series of mass spectra are generated by chromatography (e.g., liquid chromatography) and mass spectrometry. A total ion ...
... biological profiles have been obtained by means of thin-layer chromatography (TLC). This paper summarizes the application of ... liquid chromatographic techniques for the purpose of biological fingerprint analysis (BFA) of complex herbal samples. In case ... high-performance liquid chromatography (HPLC), thin-layer chromatography (TLC), gas chromatography (GC), or high-speed counter ... "Antioxidant activity assays on-line with liquid chromatography," Journal of Chromatography A, vol. 1210, no. 2, pp. 121-134, ...
... high-performance liquid chromatography (HPLC), thin-layer chromatography (TLC), gas chromatography (GC), or high-speed counter ... "Antioxidant activity assays on-line with liquid chromatography," Journal of Chromatography A, vol. 1210, no. 2, pp. 121-134, ... "Comprehensive two-dimensional high-performance liquid chromatography system with immobilized liposome chromatography column and ... Biological detection in liquid chromatography gives an opportunity to comprehensively analyze herbal samples. Apart from ...
In a pump for liquid chromatography including a cylinder and a plunger that reciprocates in the cylinder to suck and discharge ... a small-flow-rate pump that feeds the liquid by the plunger, motion conversion means that converts the rotational motion of a ... The invention provides a pump for liquid chromatography excellent in feeding liquid stably at an extremely low flow rate and in ... fluid, the pump further includes a large-flow-rate pump that feeds liquid by the plunger, ...
... the United States High-performance Liquid Chromatography(HPLC) market is valued at USD XX million in 2016 and is expected to ... 7 High-performance Liquid Chromatography(HPLC) Manufacturing Cost Analysis. 7.1 High-performance Liquid Chromatography(HPLC) ... United States High-performance Liquid Chromatography(HPLC) Market Report 2017. 1 High-performance Liquid Chromatography(HPLC) ... of High-performance Liquid Chromatography(HPLC) (2012-2022). 1.5.1 United States High-performance Liquid Chromatography(HPLC) ...
  • A procedure based on liquid chromatography/tandem mass spectrometry (LC/MS/MS) is described for the determination of nicotine and its principal metabolites cotinine, trans-3-hydroxycotinine and cotinine-N-oxide, caffeine and arecoline in breast milk, using N-ethylnorcotinine as internal standard. (nih.gov)
  • Determination of nicotine and nicotine metabolites in urine by hydrophilic interaction chromatography-tandem mass spectrometry: Potential use of smokeless tobacco products by ice hockey players. (nih.gov)
  • Liquid/liquid extraction with chloroform/isopropanol (95:5, v/v) was used for nicotine, cotinine, trans-3-hydroxycotinine, cotinine-N-oxide and caffeine under neutral conditions and for arecoline under basic conditions. (nih.gov)
  • ion exchange chromatography that utilizing ion exchange resins , to which are coupled either cations or anions that will exchange with other cations or anions in the material passed through their meshwork. (thefreedictionary.com)
  • Liquid chromatography connected with mass spectroscopy reveals that the oxidized form of rubrene is the major impurity in commercial powder of rubrene as well as in rubrene single crystals. (ebscohost.com)
  • Liquid chromatography (LC) testing and analysis. (intertek.com)
  • Doping control analysis predominantly utilises chromatography and mass spectrometry-based approaches to detect prohibited substances and methods of doping. (brighttalk.com)
  • The efficacy of MeOH as an organic modifier in temperature-responsive chromatography (TRC) was also evaluated by LC-MS analysis of steroids. (go.jp)
  • For instance, we use mass spec to support GMP stability analysis of antisense oligonucleotides (ASO) using ion-pairing (IP) reversed-phase (RP) chromatography coupled with both UV and MS detections, which cover identity, purity and impurity profile analysis of ASO. (ppdi.com)
  • Detectors for Liquid Chromatography Edited by Edward S. Yeung Written by an expert in the field, this comprehensive guide explains the basic principles behind detector response instrumentation and selected applications. (wiley.com)
  • Also With latest progression in instrumentation from an variety of specialists and produces the utilization of Liquid chromatography has turned into an effective two-dimensional hyphenated innovation for the utilization in a wide grouping of expository and bio-analytical plans for the examination of nucleic acids, amino acids, peptides, proteins, starches, lipids, and etc. (sbwire.com)
  • Advances in the Use of Liquid Chromatography Mass Spectrometry (LC-MS): Instrumentation Developments and Application, Volume 79, highlights the most recent LC-MS evolutions through a series of contributions by world renowned scientists that will lead the readers through the most recent innovations in the field and their possible applications. (elsevier.com)
  • In order to expand the range of stationary and mobile phases available in CCC and related technologies and to make use of the unique and greater dissolution capabilities of ionic liquids [ 17 ], ionic liquids have been examined as new and alternative solvents in CCC. (springer.com)
  • She is a member of many professional societies, including the American Chemical Society, the American Association of Clinical Chemists, and the American Society of Biological Chemists, Inc. In 1988 she received "The Tswett Chromatography Medal" and in 1989 she will be presented with the Dal Nogare Award. (wiley.com)