INVESTIGATION OF BENZENE METABOLISM BY LIQUID CHROMATOGRAPHY/ELECTROCHEMISTRY (THIOLS, MICROSOMES, PHENOL)
Abstract
Long term exposure to benzene has been linked to leukemia and aplastic anemia as well as a number of other blood disorders. The mechanism by which benzene elicits this carcinogenic response is not yet been fully understood. In order to identify the reactive intermediate in benzene metabolism, a sensitive analytical method is needed. Liquid chromatography/electrochemistry offers a distinct advantage over other methods of analysis for the detection and quantitation of benzene metabolites. Most of the metabolites are electroactive and are easily detectable in the picomole range. Because of the specificity of the detector few, if any electroactive compounds interfere in the analysis. All of the metabolites of interest can be identified with a high degree of certainty based on retention time and electrochemical characteristics. The primary metabolite of benzene; phenol, was identified in both mouse liver and porcine bone marrow microsomal incubations. Hydroquinone was detected in the presence in microsomal incubations of benzene and ascorbic acid. The detection of the glutathione conjugate of p-benzoquinone in microsomal incubations by liquid chromatography/electrochemistry provided strong evidence that p-benzoquinone was being produced in these incubations. The role of p-benzoquinone as a reactive intermediate in benzene metabolism was studied. Mechanisms of formation and reduction of the quinone by microsomal enzymes were investigated. The role of glutathione in the detoxification of the quinone intermediate was also investigated. This involved the use of a novel form of LCEC which allows for the simultaneous determination of thiols and disulfides.
Degree
Ph.D.
Subject Area
Analytical chemistry
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