Showing papers on "Derivatization published in 1998"
TL;DR: A novel application of the latter technique, involving a base-deactivated stationary phase and acetonitrile as mobile phase, is described that is suited to the separation of fatty acids in the form of picolinyl ester and dimethyloxazoline derivatives, as well as methyl esters.
Abstract: Procedures for structural analysis of fatty acids are reviewed The emphasis is on methods that involve gas chromatography-mass spectrometry and, in particular, the use of picolinyl ester and dimethyloxazoline derivatives These should be considered as complementing each other, not simply as alternatives However, additional derivatization procedures can be of value, including hydrogenation and deuteration, and preparation of dimethyl disulfide and 4-methyl-1,2,4-triazoline-3,5-dione adducts Sometimes complex mixtures must be separated into simpler fractions prior to analysis by gas chromatography-mass spectrometry Silver ion and reversed-phase high-performance liquid chromatography are then of special value In particular, a novel application of the latter technique, involving a base-deactivated stationary phase and acetonitrile as mobile phase, is described that is suited to the separation of fatty acids in the form of picolinyl ester and dimethyloxazoline derivatives, as well as methyl esters
341 citations
TL;DR: Reaction conditions were optimized for various classes of carboxylic acids and a uniquely rapid derivatization of amino acids in aqueous ethanol was shown to be possible and most of the analytes, e.g. acidic metabolites in physiological fluids, could be treated directly in the aqueously matrix.
263 citations
TL;DR: Main derivatization procedures for opiates, cocaine, cannabis, amphetamines, benzodiazepines and LSD have been reviewed and papers describing the analyses of drugs of abuse in matrixes other than blood, such as hair or sweat, have received special attention.
261 citations
TL;DR: The utility of ferrocene-based "electrochemically ionizable" derivatives to enhance ES-MS analysis of simple alcohols, sterols, and phenols is demonstrated using a saw palmetto (Serenoa repens) fruit extract known to contain a variety of alcohols at low levels.
Abstract: In this paper, the use of ferrocene-based "electrochemically ionizable" derivatives to enhance ES-MS analysis of simple alcohols, sterols, and phenols is discussed. These derivatives are designed to take advantage of the electrolysis process inherent to operation of the ES ion source for selective ionization. Derivatization procedures, electrochemical character of the derivatives, and the ES-MS operational parameters necessary to maximize electrochemical ionization and to enhance gas-phase detection are presented with reference to ferrocenecarbamate ester derivatives of a variety of alcohol standards, as well as the ferroceneboronate derivative of the diol, pinacol. Tandem mass spectrometric analysis of the derivatives (precursor and product ion spectra) is shown to provide derivative confirmation, enhanced detection, and additional analyte structure information. The utility of this derivatization approach for the selective detection of alcohols in complicated mixtures is demonstrated using a saw palmetto (Serenoa repens) fruit extract known to contain a variety of alcohols at low levels.
175 citations
TL;DR: The analysis of peptide derivatives by fast atom bombardment, liquid secondary-ionization mass spectrometry, plasma desorption, electrospray ionization, and matrix-assisted laser desor adaptation/ionization is reviewed.
Abstract: The analysis of peptide derivatives by fast atom bombardment, liquid secondary-ionization mass spectrometry, plasma desorption, electrospray ionization, and matrix-assisted laser desorption/ionization is reviewed. The fragmentation patterns of peptides and of charge-derivatized peptides are compared, and the proposed fragment ion structures are summarized. A variety of derivatization approaches and the distinguishing features of mass spectra produced from these derivatives are described. The most promising derivatization approaches are evaluated, and the strengths and limitations of these approaches are discussed. © 1999 John Wiley & Sons, Inc. Mass Spec Rev 17: 255–274, 1998
162 citations
TL;DR: A study of the degradation of glyphosate in environmental waters under characteristic conditions was carried out to figure out the main degradation pathways of this compound.
144 citations
TL;DR: In this article, a fully automated on-line solid-phase extraction-high-performance liquid chromatography-electrospray ionization mass spectrometry (SPE-HPLC-ESI-MS-MS) method was developed for the determination of glyphosate and its degradation product aminomethylphosphonic acid (AMPA), in the concentration range of 0.05 to 3 μg/l in various types of water.
144 citations
TL;DR: The versatility of NaBPr4 as aqueous in situ derivatization reagent for organometallic compounds is demonstrated in this article, where it is now possible to derivatize the important ethyl derivatives of lead and mercury which until now had to be derived by Grignard alkylation or hydride generation.
127 citations
TL;DR: A short overview on the various reagents that can be used for pre-, post- and on-column derivatization in CE and the emphasis is on the labelling of amino, aldehyde, keto, carboxyl, hydroxyl and sulfhydryl groups.
114 citations
105 citations
TL;DR: In this paper, a new home-designed micro-preconcentration column containing RP-C18 material as solid sorbent, accommodated in a pressure-tight housing of stainless steel, combined with an LC six port valve was used to interface the flow-injection on-line derivatization and preconcentration system to the LC equipment.
TL;DR: The development of a method for the analysis of organoarsenic compounds that combines dithiol derivatization with solid-phase microextraction sample preparation and gas chromatography-mass spectrometry (GC-MS) is described.
TL;DR: In this paper, a new FI/FTIR method for the determination of acetaminophen (paracetamol, N -acetyl- p -aminophenol) involving on-line reaction is described.
TL;DR: A reliable, high throughput method is described for the routine analysis of amino acids in food, beverages and feedstuff using a simple one-step binary gradient, with an excellent resolution and outstanding reproducibility.
TL;DR: In this article, a high-performance liquid chromatography (HPLC) method to determine the most important cellular thiols [reduced glutathione (GSH), cysteine, γ-glutamylcysteine and cysteinyl glycine] is described.
TL;DR: Hydxylamine proved to be the most useful, as the IPA-oxime was easiest to purify from plant extracts and was the most stable.
TL;DR: The proposed analytical methodology was applied to analyze pesticides in surface and ground-water samples of the Lassithi Plateau, Crete, Greece and the limit of detection for seventeen organochlorine compounds was better than 0.003 microgram/l.
TL;DR: In this paper, gas chromatographic and liquid chromatogram methods for the investigation of phenylarsenic compounds are presented. But they do not consider the use of liquid chromatography for the detection of ADAMSITE.
Abstract: Gas chromatographic (GC) and liquid chromatographic methods for the investigation of phenylarsenic compounds are presented. With gas chromatography using an electron capture detector (ECD), the chemical warfare agents PFIFFIKUS, CLARK I and CLARK II can be detected. After derivatization with mercaptans and dimercaptans the sum of diphenylarsenic compounds resp. phenylarsenic and phenylarsonic compounds can be detected as the mercapto resp. dimercapto derivatives. High performance liquid chromatography (HPLC) analysis may be used for the detection of triphenylarsenic compounds and ADAMSITE.
TL;DR: GC-MS method validation results indicate that the performance characteristics of the method fulfilled the requirements for assay methods for use in pharmacokinetic studies.
TL;DR: In this paper, a method for the determination of hydrogen peroxide and several organic peroxides by high-performance liquid chromatography with post-column UV irradiation, derivatization and fluorescence detection is described.
Abstract: A method for the determination of hydrogen peroxide and several organic peroxides by high-performance liquid chromatography with post-column UV irradiation, derivatization and fluorescence detection is described. By means of post-column UV irradiation in the presence of water organic peroxides are converted into hydrogen peroxide and organic hydroperoxides, which react rapidly with the post-column derivatization agent p-hydroxyphenylacetic acid (PHPAA) under catalysis of horseradish peroxidase to yield the fluorescent PHPAA dimer that is detected at excitation and emission wavelengths of 285 and 400 nm, respectively. The detection limit for hydrogen peroxide is 14 ng/mL, for organic peroxides between 34 ng/mL and 5 μg/mL. No interference by other compounds was observed when their concentrations were below 10 mg/mL except ethers and phenols.
TL;DR: In this paper, a procedure for the sequential, selective derivatization of cyanuric chloride that allows for the incorporation of carbohydrates and peptides has been elucidated, and large combinatorial arrays of individual derivatives, over 40,000 in all, have been produced in 50μmole quantities using automated parallel solution phase synthesis.
TL;DR: The LC-MS results confirm with confidence that the two terazosin enantiomers have different elimination profiles, and are consistent with previous results from enantioselective HPLC-fluorescence methods.
TL;DR: Derivatizations of γ-aminobutyric acid suggest that CFSE may be a practical amine-reactive fluorescent probe for the quantification of neurotransmitters in microdialysates.
Patent•
17 Aug 1998TL;DR: In this paper, the C(7) and C(10) hydroxyl groups of 10-DAB were protected or derivatized prior to the C (7) group.
Abstract: Processes for the preparation of taxol and other taxanes through selective derivatization of the C(7) and C(10) hydroxyl groups of 10-DAB, particularly a novel process using a new strategy in which the C(10) hydroxyl group is protected or derivatized prior to the C(7) hydroxyl group; and the provision of C(7) and C(10) derivatized 10-DAB compounds.
TL;DR: The applicability of the described method to the extract of atmospheric aerosol samples was demonstrated and the linearity, reproducibility and reliability of the method were evaluated.
TL;DR: The results showed that some of the L-amino acids, i.e., Glu, Asp, Ser, Gly, Ala, Thr, Pro, Lys, Phe and Met, were found in the methanol extracts of yogurt.
TL;DR: The recoveries of 53 aromatic amines in a drinking water matrix at pH 9 were determined and most anilines showed relative recoveries between 80-120% with relative standard deviations of< or = 5% at concentration levels between 10 and 20 micrograms 1(-1).
TL;DR: A method for qualitative and quantitative analysis of Fusarium mycotoxins by gas chromatography-mass spectrometry (GC-MS) using cold on-column injection was improved and Chromatographic separation of the toxins extracted from barley was achieved as a single peak.
TL;DR: In this paper, a method for simultaneous determination of glucocorticoids (GCs) in plasma or urine by high-performance liquid chromatography (HPLC) with fluorimetric detection has been developed.