Showing papers on "Derivatization published in 1985"
TL;DR: In this article, gas-phase reactions have been used to tag corona-discharge-induced chemical species on the surface of polyethylene to provide a surface count of induced species.
165 citations
TL;DR: A simple, rapid and highly sensitive method for the determination of catecholamines (norepinephrine, epinephrine and dopamine) in human plasma is described which employs high-performance liquid chromatography with fluorescence detection.
124 citations
TL;DR: The method offers a noninvasive, specific approach to the study of thromboxane synthesis and platelet function in man and is much less labor intensive than currently available methods employing electron-impact chromatography-mass spectrometry.
109 citations
TL;DR: The utility of the sodium acetate method is shown by the trace GC-mass spectrometric analysis of muramic acid and rhamnose derived from bacterial peptidoglycan-polysaccharide complexes in mammalian tissue.
102 citations
TL;DR: The principles and applications of fluorescence detection and fluorescence introducing reagents and methods in HPLC are reviewed in this paper, where the design and requirements for fluorescence detectors, flow cells and excitation sources and the conversion of non-fluorescent compounds into fluorescent products by pre-column and post-column derivatization reactions are discussed.
Abstract: The principles and applications of fluorescence detection and fluorescence introducing reagents and methods in HPLC are reviewed. The design and requirements for fluorescence detectors, flow cells and excitation sources and the conversion of non-fluorescent compounds into fluorescent products by pre-column and post-column derivatization reactions are discussed. For the applications the emphasis is on drug analysis, where possible in biological fluids (serum, urine, etc.). The last paragraphs are divided in a number of sections in which newly developed and some scarcely used reagents are mentioned shortly; a more complete treatment is given of the reagents and labels most frequently used in the derivatization of certain functional groups. In this discussion the methods of derivatization as well as the selectivity, stability, fluorescence behaviour of the reagents/labels and derivatives and the reaction conditions are included. An up-to-date survey of the applications of fluorescence detection in l...
100 citations
TL;DR: In this article, 3-Bromomethyl-6,7-dimethoxy-1-methyl-2(1 H )-quinoxalinone was found to be a selective and highly sensitive fluorescence derivatization reagent for carboxylic acids in high-performance liquid chromatography.
86 citations
TL;DR: In this paper, commercial bulk products and pharmaceutical drug formulations of aminoglycoside antibiotics obtained by fermentation (kanamycin, gentamicin, sisomicin and tobramycin) or by synthesis (amikacin) were analysed with high-performance liquid chromatography on a C 8 reversed-phase column.
78 citations
TL;DR: In two surgical patients given racemic indoprofen intravenously, the pharmacologically active (+)-enantiomer had a lower clearance and a lower distribution volume than the (-)- enantiomer, which gave it a slightly longer half-life.
65 citations
TL;DR: A high-performance liquid chromatographic method for the derivatization, identification and separation of carboxylic acids in beverages such as wines and other commercial drinks or natural fruit juices has been developed.
58 citations
TL;DR: The composition of the mobile phases had to be designed carefully in order to avoid a disturbance of the chromatographic performance on the last column, and an adequate selectivity and sensitivity was obtained by a post-column derivatization with fluorescamine.
55 citations
TL;DR: A method optimized for the determination of histamine in biological samples by means of HPLC and postcolumn o-phthalaldehyde derivatization has been developed and permits determination of Histamine even at low-picomolar levels.
TL;DR: In this article, a general scheme of an HPLC system equipped with an on-line postcolumn reaction detector is given, and the derivatization can be carried out either prior to the HPLC separation or by doing the reaction in an online postcolumn mode.
Abstract: Currently, the best and most reliable HPLC (high-performance liquid chromatography) detectors are UV-VIS absorbance, fluorescence, and electrochemical detectors. It is attractive to try to expand their range of application by using suitable chemical derivatization techniques to convert the analytes of interest with their originally poor detection properties into compounds that can be detected with high sensitivity with these detectors. Besides an improvement of the detection properties, the chemical reaction can also enhance the selectivity of the total analytical method. The derivatization can be carried out either prior to the HPLC separation or by doing the reaction in an on-line postcolumn mode. Comparative advantages and disadvantages of these two approaches have been discussed previously. This paper will discuss on-line postcolumn derivatization. A general scheme of an HPLC system equipped with an on-line postcolumn reaction detector is given. 40 references, 6 figures, 2 tables.
TL;DR: Automated high-performance liquid chromatography was used to analyse dansylhydrazine derivatives of neutral sugars in unfractionated acid hydrolysates of four well-characterized glycoproteins and confirmed that mannose is present in most preparations of human high-molecular-weight salivary glycoprotein.
TL;DR: In this paper, the effect of lignin derivatization on the performance of size-exclusion chromatography of different lignins was studied using styrene-divinylbenzene copolymer gel columns and the results showed that these phenomena did not cause any major interference in the chromatographic system described here.
TL;DR: A reversed-phase high-performance liquid chromatographic method for the determination of the skeletal muscle relaxant baclofen in human plasma and urine is described and is suitable for pharmacokinetic studies.
TL;DR: In this paper, a method for the determination of linear aldehydes (C1 −C8) in waters is described, which is directly applicable to surface waters and drinking water.
TL;DR: In this paper, the soft ionization techniques such as desorption chemical ionization, fast atom bombardment and field Desorption were used to study xanthone glycosides.
TL;DR: In this article, a method for determining nanogram amounts of carbonyl compounds was developed, which employed reversed-phase gradient liquid chromatography on 2 mm I.D. columns and methane chemical ionization.
TL;DR: In this paper, the use of solid-phase reactors for post-column derivatization in narrow-bore HPLC (1.0mm i.d. analytical columns) is evaluated.
Abstract: The use of solid-phase reactors for post-column derivatization in narrow-bore HPLC (1.0mm i.d. analytical columns) is evaluated. Two systems are described, viz. for the determination of N-methylcarbamate pesticides and for that of urea and ammonia. The solid-phase reactor is packed with a strong anion exchange resin and urease immobilized on silica, respectively, to effect the catalytic hydrolysis of the solutes eluting from the analytical column. In both systems, the hydrolysis product is reacted with o-phthalaldehyde followed by fluorescence monitoring.
TL;DR: In this article, a TSP HPLC/MS was used to analyze five Fusarium mycotoxins in porcine plasma and urine, with detection limits ranging from 1 to 10 ng of mycotoxin injected onto the HPLC column.
Abstract: Thermospray high performance liquid chromatography/mass spectrometry (TSP HPLC/MS) was used to analyze five Fusarium mycotoxins in porcine plasma and urine. Four cytotoxic trichothecene mycotoxins, T-2 toxin, HT-2 toxin, diacetoxyscirpenol (DAS), deoxynivalenol (DON), T2 tetraol, and the fungal estrogen zearalenone (F-2 toxin) were analyzed. The thermospray mass spectrum contained molecular weight information with few, if any, fragment signals. Detection limits ranging from 1 to 10 ng of mycotoxin injected onto the HPLC column were obtained using selected ion monitoring (SIM) HPLC/MS. Neither the plasma nor the urine matrix interfered with TSP HPLC/MS analysis of these mycotoxins and no sample derivatization was necessary for the analysis. The TSP HPLC/MS technique appears to be ideal for very sensitive analysis of mycotoxins in biological samples.
TL;DR: The RPLC procedure is simpler and faster than the HPLC systems and is suggested for future use in analysis of B-6 vitamer concentrations in human milk and correlated well with the microbiological assay.
TL;DR: This study describes the use of mass spectrometry (MS), high-performance liquid chromatography (HPLC) and chemical derivatization techniques for the identification of doxylamine and five rhesus monkey urinary metabolites.
Abstract: This study describes the use of mass spectrometry (MS), high-performance liquid chromatography (HPLC) and chemical derivatization techniques for the identification of doxylamine and five rhesus monkey urinary metabolites. The analyses were performed using chemical ionization mass spectrometry with either methane or ammonia as the reagent gas. The confirmation of the structures of two of these urinary metabolites was aided by the synthesis of doxylamine N-oxide and desmethyldoxylamine and by the use of methylation and acetylation derivatization techniques. Doxylamine N-oxide, desmethyldoxylamine, didesmethyldoxylamine, and two metabolites which resulted from the cleavage of the aliphatic tertiary nitrogen side chain to the subsequent 2-[1-phenyl-1-(2-pyridinyl)ethoxy]acetic acid or 2-[1-phenyl-1-(2-pyridinyl)ethoxy]methanol compounds were isolated and identified from rhesus monkey urine. Additional data concerning the mass spectral analysis of derivatization or reaction products from the three chloroformate reactions with doxylamine, and the synthesis and separation techniques which afforded mass spectral identification of the urinary metabolites are also presented.
TL;DR: In this paper, a quantitative method of analysis for urea and ammonia is described, which is based on ion-pair high-performance liquid chromatography with on-line post-column derivatization on immobilized urease.
TL;DR: The applicability and utility of the microwave sustained helium emission detector (MED) as a gas chromatographic detector can be greatly increased by utilizing elemental tagging derivatization of various functional groups such as alcohols, acids, amines, phenols or thiols as mentioned in this paper.
TL;DR: This change in phase-solubility behavior of progesterone in phosphate buffer pH 7.4 is probably due to low crystallization tendencies of the derivatives.
Abstract: The effect of γ-cyclodextrin and its four derivatives on the solubility of progesterone in phosphate buffer pH 7.4 was investigated. γ-Cyclodextrin forms a complex precipitating from solution at low cyclodextrin concentrations. No precipitation of complexes was observed with the γ-cyclodextrin derivatives. This change in phase-solubility behavior is probably due to low crystallization tendencies of the derivatives.
TL;DR: In this paper, the structure elucidation of austalides G-L based on a study of their 1H and 13C n.m.r. spectra and chemical derivatization is described.
Abstract: The structure elucidation of austalides G–L, based on a study of their 1H and 13C n.m.r. spectra and chemical derivatization, is described.