Simultaneous extraction and derivatization of 2-chlorovinylarsonous acid from soils using supercritical and pressurized fluids.

Supercritical carbon dioxide and pressurized fluids are compared for the extraction with in situ derivatization of 2-chlorovinylarsonous acid (CVAA) from a series of seven spiked soils. Samples are allowed to age (up to 42 days) and periodically extracted. Sample ageing leads to a recovery decrease due to the development of strong interactions between CVAA and matrix active sites, as time elapses.

Selective extraction of hydrocarbons, phosphonates and phosphonic acids from soils by successive supercritical fluid and pressurized liquid extractions.

Hydrocarbons, dialkyl alkylphosphonates and alkyl alkylphosphonic acids are selectively extracted from spiked soils by successive implementation of supercritical carbon dioxide, supercritical methanol-modified carbon dioxide and pressurized water. More than 95% of hydrocarbons are extracted during the first step (pure supercritical carbon dioxide extraction) whereas no organophosphorus compound is evidenced in this first extract. A quantitative extraction of phosphonates is achieved during the second step (methanol-modified supercritical carbon dioxide extraction).

Liquid chromatography analysis of phosphonic acids on porous graphitic carbon stationary phase with evaporative light-scattering and mass spectrometry detection.

The analysis of several phosphonic acids has been investigated by liquid chromatography (LC), using porous graphitic carbon as stationary phase with mass spectrometry (MS) or evaporative light-scattering detection (ELSD). In both detection modes (MS and ELSD), the mobile phase must be volatile and, due to the porous graphitic carbon (PGC) properties, should promote electronic interactions. Among the various hydrogeno- and perfluorocarboxylic acids tested, trifluoroacetic acid (0.

Identification of phosphonic acids by capillary electrophoresis-ionspray mass spectrometry.

The identification of alkylphosphonic acids in spiked tap water has been investigated by on-line capillary electrophoresis-UV spectrometry-mass spectrometry (CE-UV-MS) in negative-ion mode. The 5 mM sorbic acid-ammonia electrolyte (pH 6.5) allows simultaneous indirect UV and MS (ionspray) detection.

Pharmacological profile of CEB-1957 and atropine toward brain muscarinic receptors and comparative study of their efficacy against sarin poisoning.

This study consists of two parts, first to compare the pharmacological profile of atropine and CEB-1957 substance toward muscarinic receptor subtypes. In various rat brain structures, binding properties were determined by competition experiments of [3H]pirenzepine, [3H]AF-DX 384, and [3H]4-DAMP in quantitative autoradiography of M1, M2, and M3 muscarinic receptor subtypes, respectively. Competition curves have shown that atropine presents similar nanomolar inhibition constants toward each subtype, while CEB-1957 has distinct affinities (Ki from 0.

Capillary electrophoresis analysis of chemical warfare agent breakdown products. I. Counterelectroosmotic separation of alkylphosphonic acids and their monoester derivatives.

An analytical method has been developed for the analysis of chemical warfare agents by capillary zone electrophoresis (CZE). Sorbate anion has been selected as indirect UV-absorbing agent and decamethonium cation reduces the electroosmotic flow. The optimized electrolyte (5 mM sorbic acid, 0.

Direct enantiomeric separation of beta-blockers on ChyRoSine-A by supercritical fluid chromatography: supercritical carbon dioxide as transient in situ derivatizing agent.

The direct enantiomeric separation of a series of beta-blockers has been carried out on two chiral stationary phases (CSPs) derived from 3,5-dinitrobenzoyl tyrosine: the commercially available ChyRoSine-A and a recent improved version of this CSP. Using supercritical fluid chromatography (SFC), facile separations are achieved (1.1 less than Rs less than 7) within short analysis times.

Species differences in the generation of the chiral sulfoxide metabolite of albendazole in sheep and rats.

The prochiral anthelmintic drug albendazole was administered orally to sheep and rats. Blood samples were taken at standardized intervals during the time course of the plasma kinetics: 18 h in rats and 48 h in sheep. The enantiomeric ratio of the sulfoxide metabolite was determined by means of HPLC on a chiral stationary phase, the chiral selector of which was a N-3,5-dinitrobenzoyl derivative of (S)-tyrosine.

Direct separation of albendazole sulfoxide enantiomers by liquid chromatography on a chiral column deriving from (S)-N-(3,5-dinitrobenzoyl) tyrosine: application to enantiomeric assays on plasma samples.

The direct enantiomeric resolution of albendazole sulfoxide (SOABZ), an anthelmintic drug belonging to the benzimidazole class, is reported on a chiral stationary phase (CSP) synthesized by covalent binding of (S)-N-(3,5-dinitrobenzoyl)tyrosine-O-(2-propen-1-yl) methyl ester on a gamma-mercaptopropyl-silanized silica gel. A comparison with the resolution achieved on commercially available Pirkle-type CSPs obtained from N-(3,5-dinitrobenzoyl) derivatives of (R)-phenyglycine or (S)-phenylalanine is described. Some structurally related chiral sulfoxides including oxfendazole (SOFBZ) are also studied.

Resolution of enantiomeric amides on a Pirkle-type chiral stationary phase. A comparison of subcritical fluid and liquid chromatographic approaches.

Subcritical and supercritical fluid chromatography (SubFC and SFC) have been evaluated for the resolution of an homologous series of enantiomeric amides. The solutes were the 2-naphthoyl amides of an homologous series of amines, ranging from 2-aminobutane to 2-aminoctane, and the p-methyl-, p-methoxy- and p-chlorophenylamides of 2-aminoheptane. The chiral stationary phase (CSP) used was the covalent form of (R)-N-(3,5-dinitrobenzoyl)phenylglycine.