Showing papers on "Derivatization published in 1984"
TL;DR: The derivatization method is rapid, efficient, sensitive, and specific for the analysis of primary and secondary amino acids in protein hydrolyzates and the liquid chromatographic system allows for the rapid, bonded-phase separation with ultraviolet detection of the common amino acids.
2,543 citations
TL;DR: All amino acids, including proline, are converted quantitatively to phenylthiocarbamyl compounds and these are stable enough to eliminate any need for in-line derivatization, providing results comparable in sensitivity and precision to those obtained by state-of-the-art ion-exchange analyzers.
1,625 citations
TL;DR: The incorporation of two peptides-derived amine nitrogens and two glucose residues in FFI strongly suggests that peptide-bound FFI precursors are implicated in the crosslinking of proteins by glucose in vivo.
Abstract: Proteins exposed to glucose over long periods are known to undergo physicochemical changes including crosslinking and formation of brown fluorescent pigments of poorly characterized structure. Acid hydrolysis of both browned poly(L-lysine) and browned bovine serum albumin is found to release a major fluorescent chromophore, which after alkalinization is extractable into organic solvents and which can be purified by silica gel chromatography. The fluorescence properties of this compound very closely resemble those of the bulk browned polypeptides. By NMR, mass spectroscopy, and chemical derivatization, this compound is assigned the structure 2-(2-furoyl)-4(5)-(2-furanyl)-1H-imidazole (FFI). Confirmation was obtained by independent chemical synthesis from furylglyoxal and ammonia. The incorporation of two peptide-derived amine nitrogens and two glucose residues in FFI strongly suggests that peptide-bound FFI precursors are implicated in the crosslinking of proteins by glucose in vivo. This reaction has potential implications in the understanding of glucose-mediated protein modifications and their role in the complications of diabetes and aging.
420 citations
TL;DR: A sensitive and convenient method for the simultaneous determination of D- and L-aspartic acid in amino acid mixtures is described, which can be accurately detected in the presence of a 100-fold excess of L- aspartate.
281 citations
TL;DR: Favourable analytical conditions allowing amino acid analysis in biological fluids, acquired from small human biopsy specimens, were achieved by considering various derivatization methods, the mode of detection and the column used.
245 citations
TL;DR: The carbohydrate portion of the derivative was found to retain its sensitivity to exoglycosidases, allowing sequential enzymatic digestions for determination of sugar sequence and anomerity to be performed, and the derivatives also possessed a site of potential positive charge, making them amenable to analysis by fast-atom bombardment-mass spectrometry.
186 citations
TL;DR: In this article, negative ion chemical ionization mass spectrometry has been investigated as a potential assay method for detecting 5-HETE and leukotriene B 4 isomers.
121 citations
TL;DR: The combination of this acid hydrolysis with the above improved derivatization procedure for the gas-liquid chromatographic analysis has led to a simple, rapid, and sensitive analytical method, which has been successfully tested on three glycoproteins and two plant cell-wall polysaccharide fractions.
97 citations
TL;DR: In this paper, a method based on high-performance liquid chromatographic separation on a strong cation exchange material combined with low-wavelength ultraviolet absorbance detection is described, which forms the basis of a rapid assay procedure for glycine betaine using plant saps as the starting material and avoiding the need for derivatization.
80 citations
TL;DR: Using this technique, the pharmacokinetics of DDTC-reactive Pt(II) in humans after either i.v. infusion or infusion of DDP into the peritoneal cavity of patients with ovarian carcinoma is measured.
80 citations
TL;DR: In this article, shift reagents were added to the eluate using a post-column derivatization system and adapted in order to be compatible with the solvent system used for the chromatographic separation.
TL;DR: In this paper, a chiral derivatization and chiral mobile phase method was used to simultaneously detect common protein amino acid enantiomers on a resversed phase by column-switching technique.
TL;DR: A high-sensitivity, low-dead-volume laser-induced fluorescence detector has been designed for use in capillary column liquid chromatography and exhibits femtogram detection limits and a linear dynamic range spanning five orders of magnitude.
TL;DR: This sensitive method is applicable to the quantitative analysis of free fatty acids in normal human blood samples and blood samples from diabetic patients and shows good recovery and good reproducibility.
TL;DR: In this article, a procedure for rapid separation and microquantitative determination of various alpha-keto acids in serum and urine was developed using reverse-phase high-performance liquid chromatography.
TL;DR: In this article, a method for the determination of nitro polycyclic aromatic compounds in particulate extracts was developed and applied to the analysis of a diesel exhaust extract, and over 120 compounds were tentatively identified based on comparisons of gas chromatographic retention data of standard compounds, gas chromatography/mass spectrometry, and low-resolution mass spectral data.
Abstract: A method for the determination of nitro polycyclic aromatic compounds in particulate extracts was developed and applied to the analysis of a diesel exhaust extract. Silicic acid column chromatography combined with reduction of the nitro compounds with KBH/sub 4/ catalyzed with copper(II) chloride and derivatization with pentafluoropropionic anhydride yielded an enriched nitro fraction. Nitro polycyclic aromatic compounds present in this fraction as pentafluoropropyl amides were subsequently analyzed by capillary gas chromatography with electron capture, nitrogen-selective thermionic, and flame ionization detection and by gas chromatography/mass spectrometry. Ten nitro polycyclic aromatic compound isomers were positively identified based on comparisons of gas chromatographic retention data of standard compounds, gas chromatography/mass spectrometry, and low-resolution mass spectral data. Over 120 nitro polycyclic aromatic compounds were tentatively identified. 16 references, 4 figures, 2 tables.
TL;DR: Three fluorigenic reagents were tried in order to increase the sensitivity of the detection of various amines and o-Phthaldialdehyde (OPT) was used successfully for the derivatization of amines in red must and wine.
Journal Article•
TL;DR: In this article, a chiral derivatization and chiral mobile phase method was used to simultaneously detect common protein amino acid enantiomers on a resversed phase by column-switching technique.
Abstract: Simultaneous analysis of common protein amino acid enentiomers was achieved by a chiral derivatization and a chiral mobile phase method. In the chiral derivatization method, 2,3,4,6-tetra-O-acetyl-β- d -glucopyranosyl isothiocyanate was chosen as the reagent for the derivatization of enantiomeric amino acids to give diastereomeric thiourea derivatives. These derivatives were efficiently separated on a octadecylsilyl silica gel column by gradient elution and were detected by their absorbance at 250 nm. Derivatives of all common protein amino acid racemates, except cysteine, were resolved within about 2 h, although a few peaks were slightly overlapped. In the chiral mobile phase method, the optically active binary copper complex with N( p toluenesulphonyl)- d -phenylglycine was used as a chiral additive in the mobile phase for the ligand-exchange chromatographic resolution of underivatized d , l -amino acids. Simultaneous resolution of common protein amino acid enantiomers on a resversed phase was achieved by a column-switching technique, utilizing two ODS columns of different lengths, and by gradient elution with acetonitrile. The column eluate was monitored fluorometrically after reaction with o -phthalaldehyde.
TL;DR: A simple method for measuring the individual glycine and taurine conjugates of bile acids in bile by high-performance liquid chromatography with a C18 reversed-phase column using an isocratic solvent system of acidified methanol--potassium phosphate is developed.
TL;DR: A method has been developed to rapidly separate and quantitate levels of hydroxy-L-proline isomers in tissue hydrolysates using derivatization of the imino acids with 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole chloride followed by separation by high-performance liquid chromatography employing two C18 reverse-phase columns connected in series.
TL;DR: High-performance liquid chromatography was employed for resolution of enantiomers of chiral ring-substituted 1-phenyl-2- aminopropanes (amphetamines) and1-phenylethylamine and Cl with the amine substrates was more complete than HPLC resolution of the diastereomeric reaction products of PEIC and MTPA.
TL;DR: Commercial samples of gentamicin from different origins were analyzed by paired-ion high-performance liquid chromatography (HPLC) on a C18 bonded phase and the ratios of the four gentamicIn components were determined and compared with the compositions obtained by an independent method based on 13C NMR spectrometry.
TL;DR: An automated high-performance liquid chromatographic method for the determination of the aminoglycosides amikac in, dibekacin, gentamicin, netilmicin, sisomicin and tobramycin is described, finding it feasible for therapeutic drug monitoring.
TL;DR: The clear resolution, high degree of precision and accuracy, relatively rapid analysis and the lack of interference from chemical contaminants in feed and tissue hydrolysates render this technique suitable for routine analysis of large numbers of biological samples of nutritional interest.
TL;DR: Several chromatographic procedures for the determination of fifteen phenylurea herbicides and their corresponding degradation products are reported in this paper, which involve steps such as extraction, clean-up, catalytic hydrolysis of herbicides to anilines, liquid or gas chromatogram fractionation and/or separation, chemical derivatization and detection.
TL;DR: The determination of glutamic and gamma-aminobutyric acids in rat brain regions by derivatization with o-phthaldialdehyde-thiol, isocratic separation by liquid chromatography, and quantification by electrochemical detection provides a simple and precise method for assessing changes in glutamatergic and GABAergic neuronal systems.
TL;DR: The use of 4-bromo-2-hydroxyacetophenone trifluoromethanesulfonate ester (4'-bromophenacyl triflate) in the preparation of carboxylic acid 4-diisopropylethylammonium derivatives for spectrophotometric detection in high-performance liquid chromatography is described.
TL;DR: The proposed method was clinically applied to the determination of FFA in 0.5 ml of healthy human serum, and almost satisfactory results were obtained.
TL;DR: In this paper, a sequential derivatization of lignin with formaldehyde and phenol was investigated as a means of enhancing Lignin's reactivity in phenol-formaldehyde resins.
Abstract: A sequential derivatization of lignin with formaldehyde and phenol was investigated as a means of enhancing lignin's reactivity in phenol-formaldehyde resins. Kraft lignin (KL) and two novel biocon version lignins, steam explosion (SEL) and acid (H2SO4) hydrolysis lignin (AHL), were chemically modified by sequential reaction with formaldehyde and phenol. The results with regard to the chemical structure of the phenolic resin prepolymers showed that the ability to hydroxymethylate and phenolate is related to lignin structure. KL from pine proved to be more amenable to chemical modification with formaldehyde and phenol than was either SEL from aspen or AHL from pine. Degrees of substitution were determined by H–NMR spectroscopy and by oxidative analysis with alkaline permanganate. H–NMR spectroscopy revealed degrees of phenolation of 0.42, 0.29 and 0.21 per average C9-unit for KL, AHL, and SEL, respectively; and permanganate oxidation illustrated that approximately 90%, 60%, and 60% of all availabl...
TL;DR: In this paper, traces of C/sub 1/-C/sub 4/ alkylthiols in air were collected by using a Sep-PAK Florisil cartridge impregnated with 7-chloro-4-nitro-2,1,3-benzoxadiazole, and the adsorbed substances were eluted with methanol.
Abstract: Traces of C/sub 1/-C/sub 4/ alkylthiols in air were collected by using a Sep-PAK Florisil cartridge impregnated with 7-chloro-4-nitro-2,1,3-benzoxadiazole, and the adsorbed substances were eluted with methanol. The derivatives of the thiols produced were determined by reversed-phase high-performance liquid chromatography. The C/sub 1/-C/sub 4/ thiol vapors except for 2-methyl-2-propanethiol could be determined with 0.7-2.8% relative standard deviation in the range 1.3-6.7 nmol/L in air sample. The detection limit of the thiols were 3-139 pmol/L for 100 L of air sample. The thiol vapors from pollution sources could be successfully determined. 15 references, 4 figures, 7 tables.