Gas chromatographic-mass spectrometric determination of british anti-lewisite in plasma.

British anti-Lewisite (BAL) (2,3-dimercapto-1-propanol) is a potential therapeutic compound when used against the effects of cutaneous sulfur mustard, and a method for its determination in plasma has been developed. BAL and the internal standard (IS) ethane dithiol were isolated from plasma samples through solid-phase extraction and then reacted with 1-pentafluoropropionylimidazole, forming stable pentafluoropropionyl derivates that are sensitive to gas chromatographic-mass spectrometric analysis. Examination of concentration versus peak-area ratios of the BAL and IS derivatives demonstrated the method to be linear over a concentration range of 0.48 to 124 ng/mL in plasma when fit to a weighted (1/y2) least-squares regression. Correlation coefficients were 0.9943 to 0.9995 for six runs, and coefficients of variation (CV) were 2.5 to 8.7% over the eight concentrations tested. The intra- and interday accuracy and precision of this method was measured by examining six groups of eight unknown test samples (n = 6). Intraday accuracy, as expressed by percent error, was found to range from -15.4 to 0.21%, whereas the precision, expressed as %CV, was less than 9.8% over all sample concentrations. Interday test unknown sample results were similar in that the accuracy was shown to be -7.1 to 0.4%, and precision was 4.7 to 9.5%. BAL levels in frozen plasma (-70 degrees C) remained constant for more than 14 days with a CV of less than 10% for the eight concentrations tested. The data indicate that the method will provide accurate and precise determination of BAL at concentrations down to approximately 1 ng/mL in plasma. This procedure has been applied to determine preliminary time-concentration profile studies of BAL in the hairless guinea pig.

Biomonitoring of exposure to lewisite based on adducts to haemoglobin.

The development of a procedure for retrospective detection and quantitation of exposure to the arsenical dichloro(2-chlorovinyl)arsine (lewisite; L1) has been initiated. Upon incubation of human blood with [14C]L1 (20 nM-0.2 mM) in vitro, more than 90% of the total radioactivity was found in the erythrocytes and 25-50% of the radioactivity becomes associated with globin. Evidence was obtained for the presence of several binding sites. One type of binding was identified as L1-induced crosslinking of cysteine residues 93 and 112 of the beta-globin chain. A method was developed for extraction of bound and unbound 2-chlorovinylarsonous acid (CVAA), a major metabolite of L1, from whole blood after treatment with 2,3-dimercapto-1-propanol (BAL). Subsequent to derivatization with heptafluorobutyryl imidazole, the CVAA-BAL derivative could be analysed at a 40-fmol level by means of gas chromatography-mass spectroscopy (GC-MS) under electron impact conditions. With this procedure, in vitro exposure of human blood to 1 nM L1 could be determined. The same procedure was applied to the analysis of human urine samples spiked with CVAA. In vivo exposure of guinea pigs could be established at least 240 h after subcutaneous administration of the agent (0.25 mg/kg) by the determination of bound and unbound CVAA in the blood. In the urine of these animals, CVAA could be detected for 12 h after exposure.