Showing papers on "Derivatization published in 1981"
TL;DR: An amino acid dansylation procedure compatible with reversed-phase high-performance liquid chromatography is presented, which provides high yield derivatization while the yield appears to be independent of the ratio of dansy chloride to amino acid over a 1000-fold range.
390 citations
TL;DR: A tritium-labeled analogue is added during the extraction as an internal standard, which allows determination of recovery for each sample and simultaneously assures quantitative accuracy of the determination of the three known juvenile hormones in insect tissue.
163 citations
TL;DR: In this paper, two chiral reagents, 2,3,4,6-tetra-O-acetyl-β d -glucopyranosyl siothiocyanate and 2, 3,4-tri-O -acetyl,α-α-d -arabinopyrano-yl-isothiamyl isothianate, were used for reversed-phase liquid chromatographic resolution of enantiomeric free amino acid enantiomers.
149 citations
TL;DR: The method was applied for preparative separation of highly complex glycolipids with blood group activity and the separation pattern was highly reproducible.
146 citations
TL;DR: A high-pressure liquid chromatographic method for the measurement of short- and medium-chain-length acyl-CoA compounds is described, and methods and optimal conditions are presented for the analysis of malonyl- coA, glutathione- CoA, dephospho-Coa, and oxidized CoA in tissue extracts.
136 citations
1 Jan 1981
99 citations
TL;DR: A very sensitive and specific method of 2-ketoacid determination in various biological fluids using gas chromatography chemical ionization mass spectrometry of O-trimethylsilyl-quinoxalinol derivatives is described, which has been applied successfully to various metabolic disorders characterized by an accumulation of aliphatic 2- ketoacids.
Abstract: A very sensitive and specific method of 2-ketoacid determination in various biological fluids using gas chromatography chemical ionization mass spectrometry of O-trimethylsilyl-quinoxalinol derivatives is described. After derivatization with o-phenylenediamine in acidic medium and extraction, the 2-ketoacids, and the 2-ketovaleric acid used as internal standard, are silylated and resolved on a capillary column and their concentrations automatically determined by monitoring the m/z values corresponding to their respective protonated molecular ions, using ammonia as reactant gas. The detection limit is below 50 ng ml-1 of each 2-ketoacid. The recoveries of 2-ketoacids from urine and plasma were between 97 and 104%. Problems encountered with interfering substances were tested for and discussed. This method has been applied successfully to various metabolic disorders characterized by an accumulation of aliphatic 2-ketoacids. The metabolic interrelationship of branched chain 2-ketoacids and other compounds, especially pyruvate, is discussed.
98 citations
TL;DR: A liquid-chromatographic assay for cyclosporin A in blood and plasma is described that is sensitive enough to allow quantitation of the drug at concentrations observed clinically, is isocratic, required no derivatization, and takes only 10 min of analysis time.
Abstract: We describe a liquid-chromatographic assay for cyclosporin A in blood and plasma. The method is sensitive enough to allow quantitation of the drug at concentrations observed clinically, is isocratic, required no derivatization, and takes only 10 min of analysis time.
TL;DR: In this paper, per-O-benzoyl oligosaccharides were obtained using high performance liquid chromatography, and the best resolution was obtained on an Ultrasphere octyl column.
TL;DR: In this paper, a new class of oxirane carboxylic acids having blood-glucose-lowering activity was determined simultaneously be fluorescence labelling with 4-bromomethyl-7-methoxycoumarin (Br-Mmc) followed by separation by high-performance liquid chromatography.
TL;DR: The derivatization chemistry for conversion of mixtures of oligopeptides to the corresponding N-α, (ω)-trifluoroethyl-O-trimethylsilyl polyamino alcohols, the derivatives of choice for the sequencing of polypeptides by gas chromatographic mass spectrometry, has been optimized and resulted in a five- to tenfold increase in sensitivity over previous methods.
Abstract: The derivatization chemistry for conversion of mixtures of oligopeptides to the corresponding N-α, (ω)-trifluoroethyl-O-trimethylsilyl polyamino alcohols, the derivatives of choice for the sequencing of polypeptides by gas chromatographic mass spectrometry, has been optimized. The improvements have minimized undesirable side reactions and resulted in a five- to tenfold increase in sensitivity over previous methods employing either lithium aluminum deuteride or hexadeuterodiborane as the reducing agent. For derivatives of certain very polar peptides increases in yield have exceeded 100-fold. The procedure has been evaluated with mixtures of synthetic oligopeptides and used in the course of the determination of the amino acid sequence of the membrane protein bacteriorhodopsin, as well as other proteins.
TL;DR: Data obtained with field desorption mass spectrometry provide, for the first time, measurement of intact, chemically underivatized oligopeptides extracted form biologic matrices and significantly, provide and analytic method to calibrate radioimmunoassay data.
TL;DR: A simple and fast method based on a fluorescence derivatization of the sulfhydryl group combined with a reversed-phase liquid chromatograhic separation and fluorescence detection permits a simple determination of D-penicillamine in serum at therapeutic levels.
TL;DR: The precision, reproducibility and sensitivity of the quantitation of cholesterol with this method were acceptable, and the values of HDL-cholesterol determined by this method correlated well with those found by the heparin-manganese chloride precipitation method.
Abstract: A simple and rapid method for the quantitation of cholesterol in human serum lipoproteins (VLDL, LDL, HDL2, and HDL3) was developed (1). The content of cholesterol in each lipoprotein fraction was determined by means of a commercial enzymatic reaction kit after separation by high performance liquid chromatography with gel permeation columns. The quantitation of cholesterol could be performed with only 10-20 mu l of serum in less than 50 min by measuring A550 after passing the mixed eluate and enzyme solution through an on-line reactor system of a high-speed chemical derivatization liquid chromatograph. The precision, reproducibility and sensitivity of the quantitation of cholesterol with this method were acceptable, and the values of HDL-cholesterol determined by this method correlated well with those found by the heparin-manganese chloride precipitation method (r=0.958, n=93).
TL;DR: In this paper, a new derivatization reagent for use in liquid chromatographic separation of hydroxyl compounds has been developed, 4-dimethylamino-1-naphthoyl nitrile, was readily prepared from the corresponding acid chloride by the exchange reaction with trimethylsilyl cyanide.
Abstract: A new sensitive derivatization reagent for use in liquid chromatographic separation of hydroxyl compounds has been developed. A suitable reagent for this purpose, 4-dimethylamino-1-naphthoyl nitrile, was readily prepared from the corresponding acid chloride by the exchange reaction with trimethylsilyl cyanide. Condensation of a hydroxyl compound with the reagent was effected in the presence of triethylamine under the mild condition. The resulting ester was highly responsible for a fluorescence detector with a detection limit of 200 pg.
TL;DR: The analytical approach described allows for the rapid screening and concurrent quantitative determination of all of the major metabolites of the cyclooxygenase pathway of arachidonic acid, including the primary prostaglandins PGE2, PGD2 and PGF2 alpha in addition to the stable end-products of short-lived prostacyclin and thromboxane A2.
Abstract: The analytical approach described allows for the rapid screening and concurrent quantitative determination of all of the major metabolites of the cyclooxygenase pathway of arachidonic acid, including the primary prostaglandins PGE2, PGD2 and PGF2 alpha in addition to the stable end-products of short-lived prostacyclin and thromboxane A2 (6-keto-PGF1 alpha and TXB2, respectively), generated by incubating arachidonic acid with mouse peritoneal macrophage cells. After derivatization into the corresponding methyl ester-methoxime-TMS derivative, the extracted endogenous compounds were analysed by combined high efficiency glass capillary column chromatography and selected ion monitoring. Comparatively lower detection limits can be achieved with the methyl ester-butylboronate-TMS derivatives (e.g. 10 pg for 6-keto-PGF1 alpha). A brief account is also presented on a new type of mixed methyl ester-pentafluorobenzyloxime-butylboronate-TMS derivative of TXB2 and 5-keto-PGF1 alpha.
TL;DR: In this article, the fluorescamine reaction for primary amines has been used for the post-column derivatization of three chloroanilines at relatively low pH values, and separation was carried out on a CN-modified bonded phase with acetonitrile-water (pH 3) as the mobile phase.
TL;DR: In this paper, the p-bromophenacyl esters of acetic, propionic and butyric acids were derived using an extractive alkylation mechanism from ageous solutions.
TL;DR: An analytical procedure was developed for the determination of 6-mercaptopurine in plasma using gas chromatography-mass spectrometry with multiple-ion detection and the selectively of the method to azathioprine and to metabolites was thoroughly investigated.
TL;DR: An extensive survey of the use of these methods for the analysis of various (classes of) compounds is given in this paper, with special reference to their determination in biological matrices.
TL;DR: In this paper, 2-Naphthyl chloroformate (NCF) was found to be a suitable fluorescence reagent for the derivatization of drugs containing a tertiary amino group.
TL;DR: An efficient extraction procedure for the isolation of prostaglandins from biological samples for their subsequent quantification by gas chromatography-electron capture detection (GC-ECD) is described and the overall recovery of PGs is 60%.
TL;DR: The structures of austalides A and E, five new mycotoxins isolated from cultures of Aspergillus ustus, are based on the X-ray crystallographic study of Austalide A, chemical derivatization, and correlation of their 13C and 1H n.m.r spectral data as discussed by the authors.
Abstract: The structures of austalides A–E, five new mycotoxins isolated from cultures of Aspergillus ustus, are based on the X-ray crystallographic study of austalide A, chemical derivatization, and correlation of their 13C and 1H n.m.r spectral data.
TL;DR: In this article, a method for the trace determination of iodinated thyronines with differentiation of the optical isomers by high performance liquid chromatography (HPLC) is described, which is effected by means of a catalytic principle based on the iodide-catalysed reaction of chloramine-T and N,N′-tetramethyldiaminodiphenylmethane, producing a coloured complex that can be measured spectrophotometrically at 600 nm.
TL;DR: A high-pressure liquid chromatographic analysis of phenylpropanolamine in human plasma following extraction, back-extraction, and O-phthalaldehyde derivatization is presented and is sufficiently sensitive to quantitate as little as 5 ng of drug/ml of plasma.