Showing papers on "Derivatization published in 1995"
Book•
1 Jan 1995
TL;DR: In this article, the authors present a survey of the state-of-the-art analytical techniques in the field of chemical analysis, including the following: Atomic mass spectrometry.
Abstract: Activation analysis. Adhesives and Sealants. Air analysis. Alkaloids. Amino Acids. Amperometry. Amplification Reactions. Analytical reagents. Archaeometry and antique analysis. Arsenic (speciation). Asbestos. Atomic absorption spectrometry. Atomic emission spectrometry. Atomic fluorescence spectrometry. Atomic Mass Spectrometry. Bioassays. Bioluminescence. Bleaches and Sterilants. Blood and Plasma. Buffer Solutions. Building materials. Cadmium (speciation). Capillary Electrochromatography. Capillary Electrophoresis. Carbohydrates. Carbon. Cement. Centrifugation. Ceramics. Cerebrospinal Fluid. Chemical Warfare Agents. Chemiluminescence. Chemometrics. Chiroptical Analysis. Chlorofluorocarbons and other halocarbons. Chromatography. Clinical analysis. Coal and Coke. Colour Measurement. Computer Modelling. Conductimetry and oscillometry. Cosmetics and Toiletries. Derivatization of Analytes. Dioxins. Distillation. DNA Sequencing. Drug metabolism. Electrogravimetry. Electrolytes in physiological samples. Electron Energy Loss Spectrometry (EELS). Electron spin resonance spectroscopy. Electrophoresis. Elemental speciation. Endocrine Disrupting Chemicals. Environmental analysis. Enzymes. Essential Oils. Ethanol. Extraction. Extraction: solvent extraction. Fertilizers. Field Flow Fractionation. Fire Assay. Flow analysis. Flow injection analysis. Fluorescence. Foam Fractionation and Floatation. Food and nutritional analysis. Forensic sciences. Fourier transform techniques. Fuel. Functional group analysis. Gas chromatography. Gastric Juices. Geochemistry. Glasses. Gravimetry. Haemoglobins. Headspace analysis. Herbicides. History of Analytical Science. Hormones. Humic and Fulvic Compounds. Immunoassays. Indicators. Infrared spectroscopy. Ion. Ion exchange. Ion-selective electrodes. Isotope Dilution Analysis. Isotope Ratio Measurements. Kinetic methods. Lab-on-a-chip Technologies. Laser-based techniques. Lead. Lipids. Liquid chromatography. Mass spectrometry. Membrane. Mercury (speciation). Micellar Electrokinetic Chromatography. Micro Total Analytical Systems ( TAS). Microbiological techniques. Microelectrodes. Microscopy. Microwave Spectroscopy. Molecular Emission Cavity Analysis. Molecularly imprinted polymers. Nitric oxide: biological functions and detection. Nitrogen (speciation). Nitrosamines. Nuclear magnetic resonance spectroscopy. Nucleic acids. Optical spectroscopy. Ozone. Paints. Particle size analysis. Peptides. Perfumes. Personal Monitoring. Pesticides. pH. Pharmaceutical analysis. Pharmacokinetics. Phosphorescence. Phosphorus (speciation). Photoacoustic Spectroscopy. Pigments. Plastics. Polarography. Polychlorobiphenyls. Polycyclic aromatic hydrocarbons. Polymerase chain reaction (PCR). Polymers. Potentiometric Stripping Analysis. Precious Metals. Prions. Process analysis. Proteins. Proteins. Proteomics. Purines, pyrimidines and nucleotides. Qualitative analysis. Quality assurance. Radiochemical. Raman spectroscopy. Remote gas sensing. Sample dissolution for elemental analysis. Sample Handling. Sampling. Saponins. Segmented flow analysis. Selenium (speciation). Sensory Evaluation. Sequential injection analysis. Solvents. Speciation Analysis. Spectroelectrochemistry. Spectrophotometry. Spot Tests. Structural Elucidation. Sublimation. Sulfur and its Inorganic Compounds. Supercritical fluid chromatography. Surface analysis. Surfactants and detergents. Sweeteners. Textiles. Thermal analysis. Thin-layer chromatography. Thin-layer chromatography. Tin (speciation). Titrimetry. Toxins. Vitamins. Voltammetry. Volumetric gas measurements. Water analysis. Water determination. X-Ray techniques. Zone Refining.
907 citations
Patent•
27 Apr 1995TL;DR: In this paper, derivatized supports which are useful in solid phase synthesis of peptides, oligonucleotides or other small organic molecules as well as arrays of ligands are presented.
Abstract: Methods and derivatized supports which are useful in solid-phase synthesis of peptides, oligonucleotides or other small organic molecules as well as arrays of ligands. The methods provide means to control the functional site density on a solid support. Some of the derivatized supports are polymer-coated or glycan-coated. Other methods for regenerating the surface of a used ligand array are also provided.
565 citations
TL;DR: Two analytical methods, one involving the combined use of reverse-phase HPLC and electrochemical detection (HPLC-EC) and one involving a mass spectrometric detection after gas chromatography separation (GC/MS), were developed for the detection of 8-oxoguanine in DNA.
Abstract: Two analytical methods, one involving the combined use of reverse-phase HPLC and electrochemical detection (HPLC-EC) and one involving a mass spectrometric detection after gas chromatography separation (GC/MS), were developed for the detection of 8-oxoguanine in DNA. In order to obtain quantitative results, 2,6-diamino-8-oxopurine, whose chemical structure and electrochemical response are very similar to 8-oxoguanine, has been employed as an internal standard in the HPLC-EC assay. In the case of the GC/MS method, an isotopically stable (M + 4) 8-oxoguanine has been employed as an internal standard. Both methods are able to detect approximately 1 modification per 10(6) DNA bases. The background level of 8-oxoguanine in DNA as determined by GC/MS is approximately 50-fold higher than that determined by the HPLC-EC assay. The discrepancy between the two methods is due to an artifactual oxidation of guanine during the derivatization reaction as demonstrated by using pure guanine. The amount of 8-oxoguanine in guanine, determined by GC/MS, increases linearly with the time of derivatization, indicating that an oxidation occurs during the silylation reaction. Derivatization under nitrogen atmosphere reduces but does not suppress the artifactual oxidation. The amount of 8-oxoguanine in DNA, quantified by GC/MS, is comparable to that obtained by HPLC-EC when 8-oxoguanine is prepurified by HPLC or by immunoaffinity chromatography, prior to the silylation reaction. The artifactual formation of 8-oxoguanine during the derivatization reaction may explain, at least in part, why the values reported for 8-oxoguanine determination by GC/MS are generally about 1 order of magnitude higher than that determined by HPLC-EC. Prepurification of 8-oxoguanine from guanine is recommended in order to obtain reliable results by GC/MS which may be compared to HPLC-EC.
213 citations
TL;DR: An efficient, sensitive and reliable method for the simultaneous determination of dabsyl derivatives of numerous proteinogenic and physiological amino acids and biogenic amines in complex matrices by reversed-phase highperformance liquid chromatography (RP-HPLC) is described in this article.
208 citations
TL;DR: In this article, solid phase microextraction (SPME) is combined with GC-FID to analyze less polar acids (C 6 -C 10 ) containing relatively long hydrocarbon chains from aqueous samples with ppt detection limits.
Abstract: Solid-phase microextraction (SPME) is a simple, fast, economic, and solvent-free sample preparation method. The sensitivity of this technique for the determination of fatty acids in water can be enhanced with the addition of strong acid and salt to the aqueous phase. Under the low-pH and saturated salt conditions, SPME combined with GC-FID can analyze less polar acids (C 6 -C 10 ) containing relatively long hydrocarbon chains directly from aqueous samples with ppt detection limits. The RSD of the method was <5% for all compounds tested. Under the same conditions as above, the detection limits of free short-chain fatty acids (C 2 -C 4 ) in the aqueous samples are in the high ppb level. However, the detection limits can be lowered with in situ derivatization of these acids directly in the SPME polymeric coating doped with a derivatizing reagent. Headspace SPME/derivatization has been investigated, and the target analytes can be quantified with GC/MS by comparing the ratio of the native analytes with that of spiked isotopically labeled analogues. For air analysis, quantitative derivatization of short-chain fatty acids has been achieved. SPME without derivatization was also used to extract C 3 and C 4 acids from air samples, demonstrating the potential of SPME to monitor very polar, relatively volatile acids in air.
195 citations
Book•
1 Jan 1995
TL;DR: In this article, El Rassi et al. proposed a modified phase and hydrophobic interaction chromatography of carbohydrates and glycoconjugates for analysis by HPLC and HPCE.
Abstract: Part 1. The Solute. 1. Preparation of carbohydrates for analysis by HPLC and HPCE (A.J. Mort, M.L. Pierce). Part 11. Analytical and Preparative Separations. 2. Reversed-phase and hydrophobic interaction chromatography of carbohydrates and glycoconjugates (Z. El Rassi). 3. High performance hydrophilic interaction chromatography of carbohydrates with polar solvents (S.C. Churms). 4. HPLC of carbohydrates with cation- and anion-exchange silica and resin-based stationary phases (C.G. Huber, G.K. Bonn). 5. Analysis of glycoconjugates using high-pH anionexchange chromatography (R.R. Townsend). 6. Basic studies on carbohydrate - protein interaction by high performance affinity chromatography and high performance capillary affinity electrophoresis using lectins as protein models (S. Honda). 7. Modem size exclusion chromatography of carbohydrates and glycoconjugates (S.C. Churms). 8. High performance capillary electrophoresis of carbohydrates and glycoconjugates (Z. El Rassi, W. Nashabeh). 9. Preparative HPLC of carbohydrates (K.B. Hicks). Part III. The Detection. 10. Pulsed electrochemical detection of carbohydrates at gold electrodes following liquid chromatographic separation (D.C. Johnson, W.R. LaCourse). I 1. On-column refractive index detection of carbohydrates separated by HPLC and CE (A.E. Bruno, B. Krattiger). 12. Mass spectrometry of carbohydrates and glycoconjugates (C.A. Settineri, A.L. Burlingame). 13. Evaporative light scattering detection of carbohydrates in HPLC (M. Dreux, M. Lafosse). 14. Chiroptical detectors for HPLC of carbohydrates (N. Purdie). 15. Pre- and post-column detection-oriented derivatization techniques in HPLC of carbohydrates (S. Hase). 16. Post-column enzyme reactors for the HPLC determination of carbohydrates -(L.J. Nagels, P.C. Maes). 17. Other direct and indirect detection methods of carbohydrates in HPLC and HPCE (Z. El Rassi, J.T. Smith).
123 citations
TL;DR: The OPA-NAC technique was optimized for the detection and enantiomeric resolution of alpha-dialkylamino acids in geological samples which contain a large excess of protein amino acids.
119 citations
TL;DR: This method was used to determine NA in brain extracellular fluid: a peak corresponding to a basal level of 5 x 10(-9) M endogeneous NA was observed in microdialysates from the medial frontal cortex of the rat, and its nature was confirmed by both electrophoretic and pharmacological validations.
Abstract: Determination of catecholamines by capillary zone electrophoresis with laser-induced fluorescence detection was performed on low-concentration samples, which were derivatized with naphthalene-2,3-dicarboxaldehyde to give highly fluorescent compounds. When the borate concentration in the derivatization medium was decreased from 130 to 13 mM, sensitivity for noradrenaline (NA) and dopamine (DA) was greatly enhanced while resolution between these two compounds decreased. A 50 mM borate concentration in derivatization medium was chosen since it provided maximal resolution between NA and DA, together with a high separation efficiency (3.1 million theoretical plates per meter for DA). The injection of 2.4 nL of a NA and DA solution derivatized at 10(-9) M produced peaks with signal-to-noise ratio of 8:1 and 3:1, respectively, corresponding to 1.8 amol of each catecholamine. The calibration curves were linear when NA and DA solutions were derivatized at concentrations ranging from 10(-6) to 10(-9) M. This method was used to determine NA in brain extracellular fluid: a peak corresponding to a basal level of 5 x 10(-9) M endogeneous NA was observed in microdialysates from the medial frontal cortex of the rat, and its nature was confirmed by both electrophoretic and pharmacological validations.
117 citations
TL;DR: Three microbore liquid chromatography assays for determination of amino acids in rat brain dialysates are described, with a 5-fold increase in sensitivity for GABA and fast measurement of glutamate and aspartate.
110 citations
TL;DR: In this article, two approaches to the chiral separation of racemic mixtures of amino acids by means of capillary electrophoresis have been evaluated, i.e., indirect separation of diastereomers formed by derivatization with (+)- or (−)-1-(9-fluorenyl)ethyl chloroformate.
101 citations
TL;DR: The proposed gas chromatographic-mass spectrometric method can be used as a complement or alternative to microscopy and culturing for measuring fungal biomass in air-borne organic dust.
TL;DR: Levels of 8-hydroxyguanine in calf thymus DNA were lower than those recently found by gas chromatography-mass spectrometry but similar to those determined by high-performance liquid chromatography with electrochemical detection.
TL;DR: This HPLC assay with o-phthalaldehyde precolumn derivatization is used to measure the total, oxidized, and protein-bound forms of glutathione in human blood, plasma, and rat tissue and showed high sensitivity and good precision.
Abstract: This HPLC assay with o-phthalaldehyde precolumn derivatization is used to measure the total, oxidized, and protein-bound forms of glutathione in human blood, plasma, and rat tissue. Total glutathione (i.e., sum of reduced, oxidized, and protein-bound fractions) was determined after reduction with dithiothreitol and protein precipitation with perchloric acid (PCA). A preliminary selective blockage of free sulfhydryl groups with N-ethylmaleimide was necessary to evaluate the different oxidized forms. The assay showed high sensitivity ( 0.999). Samples, after PCA acidification, were stable at room temperature and 4 degrees C for 3 days, and at -20 degrees C and -80 degrees C for > 1 month. The method (involving automated derivatization) not only is very rapid and simple but also allows immediate processing of many different biological samples.
TL;DR: Since its introduction as an analytical technique capillary electrophoresis has been used for the separation of amino acids and their enantiomers and over 150 studies have been published to date, this review deals with their separation and detection.
Abstract: Since its introduction as an analytical technique capillary electrophoresis has been used for the separation of amino acids and their enantiomers; over 150 studies have been published to date. This review deals with their separation and detection. Amino acids have been resolved using both capillary zone electrophoresis and micellar electrokinetic chromatography. Pre-column derivatization schemes which are employed for the sensitive detection of amino acids are discussed. Criteria for the selection of the pre- or post-column derivatizing agent, chromophore or fluorophore, are presented. Detection systems, direct and indirect, that have been used are given with emphasis on fluorogenic reagents and laser induced fluorescence detection. Also, procedures for the separation of amino acid enantiomers are discussed and illustrated.
TL;DR: The results show that it is possible to use this reversed-phase HPLC assay to determine the polyamine content in P388 cancer cells and is now being used to evaluate the uptake of various polyamines by P388cancer cells and by other cancer and parasitic cells.
TL;DR: The fluorophore 2-aminoacridone has been used to label a number of branched oligosaccharides previously released from various glycoproteins and treatment of glycans with N-acetyl neuraminidase provided useful and additional structural information.
TL;DR: Using a fully automated liquid chromatograph, d - and l -α-amino acids ( d -a nd l -AA) were determined in foods and beverages by precolumn derivatization with o-phthaldialdehyde (OPA) combined with the chiral thiol N-isobutyryl- l -cysteine (IBLC) or its enantiomer N-isoindoles with the structure (CH3)2 CHCONHCH(CH2SH)COOH).
TL;DR: To enhance the applicability of direct DIO-LIF detection in CE, a derivatization method for amines was developed, and tyramine was determined in urine before and after the consumption of cheese to show that derivatized preserves the separation efficiency of CE for the analytes examined.
TL;DR: In this article, a procedure for the formation of trimethylsilyl esters of alkylmethylphosphonic acids using 1% trimethylchlorosilane in bis-(trimethyl silyl)trifluoroacetamide as a derivatizing agent is described.
TL;DR: The reversed-phase HPLC separation of fluorescent o-phthalaldehyde (OPA) derivatives has been applied to the assay of hepatic gamma-glutamylcysteine and glutathione levels and the enzymes producing these peptides and the two methods correlate well.
TL;DR: The enantiomers of the related substances methamphetamine, ephedrine, pseudoephedrine and methcathinone were determined by both gas chromatography after derivatization and by nuclear magnetic resonance using a chiral solvating agent.
TL;DR: In this article, various aldehyde derivatives were used for the determination of volatile aldehydes in gaseous or air samples in order to investigate the behaviour of aldeheroides in air and their contribution to air pollution.
TL;DR: The suitability of the ANTS derivatization and the subsequent separation for the analysis of complex oligosaccharide patterns is demonstrated with oligosACcharide libraries derived from ovalbumin and bovine fetuin.
TL;DR: A multi-element, element-specific detector for gas chromatography (GC) based on atomic emission spectroscopy (AES) with a microwave induced plasma (MIP) source was tested on some environmental samples.
Abstract: A multi-element, element-specific detector for gas chromatography (GC) based on atomic emission spectroscopy (AES) with a microwave induced plasma (MIP) source was tested on some environmental samples. As derivatization procedure, direct aqueous phase ethylation and chelation/extraction followed by Grignard reaction were tested on the following ions: methylmercury, ethylmercury, phenylmercury, mercury(II), trimethyllead, dimethyllead, lead(II), trimethyltin, dimethyltin, triethyltin, tripropyltin, tributyltin, dibutyltin, butyltin, and tin(IV). For mercury species a direct aqueous phase phenylation was successfully tested. The different methods of derivatization are compared, and the performance (sensitivity, linearity) of the GC-MIP-AES system is discussed. Some examples of application to environmental samples (biological tissues) are given.
TL;DR: In this article, solid-phase extraction was used simultaneously to clean up and concentrate samples prior to automatic derivatization to determine fifteen biogenic amines in wine from the Tarragona region.
TL;DR: In this article, the authors used a sheath flow cuvette as a post-column detector and excitation by the 488-nm argon ion laser line to obtain a limit of detection of 9.0 zeptomoles for the CBQ-arginine derivative.
TL;DR: D-Amino acids in biological samples were easily determined utilizing the present derivatization with NBD-F, enantiomeric separation and fluorometric detection following deproteinization of biological samples (serum or brain homogenate) with methanol and centrifugation.
Abstract: The enantiomeric separations of D,L-amino acids derivatized with fluorogenic reagents, 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F), 4-(N,N-dimethylaminosulphonyl)-7-fluoro-2,1,3-benzoxadiazole (DBD-F) and 4-aminosulphonyl-7-fluoro-2,1,3-benzoxadiazole (ABD-F) by high-performance liquid chromatography (HPLC) on various Pirkle type chiral stationary phases (CSPs, Sumichiral OA series) with citric acid in methanol as a mobile phase were studied. Since the least retention and no separation was observed for the derivatives of racemic phenylalanine methyl-ester, -amide and a drug without an alpha-carboxyl group, the carboxylic acid group of the amino acid derivatives seemed to contribute to the enantioselective fixation of the derivatives through hydrogen bonding on the N-acyl-amino acid amide moiety of the CSP. The enantioselective retention of the derivatives was attained through the (S) or (R) configuration of valine, phenylglycine, naphthylglycine, naphthylethylamine or the tert-leucine moiety in the CSP. The 2,1,3-benzoxadiazole (benzofurazan) moiety in the derivatives helps the effective fixation of the derivatives through a pi-pi interaction with an aromatic moiety such as a 3,5-dinitrophenyl or naphthyl group in the Pirkle type chiral stationary phases. D-Amino acids in biological samples were easily determined utilizing the present derivatization with NBD-F, enantiomeric separation and fluorometric detection (530 nm em/470 nm ex) following deproteinization of biological samples (serum or brain homogenate) with methanol and centrifugation. The applications of the method were clearly demonstrated by the following results; D-Ala was detected in sera of healthy volunteers at a level of 0.48-3.10 microM. D-Lys was found in the serum of a patient with myeloma and requiring renal dialysis, and D-Ser was found in rat and bovine cerebrum. Peak identification was performed by use of different types of stationary phases especially those bearing the opposite configuration to that of the chiral centre.
TL;DR: In this article, a method for the analysis of monosaccharide enantiomers of the aldose type is described, where Aminoalditols resulting from derivatization with S-(−)-1-phenylethylamine were subjected to capillary electrophoresis in a borate buffer.
TL;DR: Preliminary results indicate that the (R)-enantiomer of both isoquinoline derivatives predominate in the human brain.