A simplified methodology for quantitation of butadiene metabolites. Application to the study of 1,3-butadiene metabolism by rat liver microsomes.

A rapid, simple extraction and GC assay procedure is described that allows quantitation of micromolar concentrations of butadiene bisoxide and 3-butene-1,2-diol in microsomal suspensions exposed to butadiene. Butane-1,4-diol is used as the internal standard. The recovery of these compounds from aqueous media was almost quantitative, and calibrations for each compound were linear from 10(-6) to 10(-3) M. In this system butadiene monoxide and crotonaldehyde can be rapidly quantitated at micromolar concentration by headspace sampling, using methanol or n-butanol as the internal standard. In addition, the synthesis and chemical characterization of diastereomeric 3,4-epoxybutane-1,2-diols are described. It is demonstrated that the epoxy diol, although not extractable from aqueous solutions by ethyl acetate, can be recovered upon evaporation of aqueous media, followed by ethyl acetate extraction. Direct GC quantitation of the epoxy diol was linear from 10(-5) to 10(-3) M. This procedure facilitated the examination of butadiene metabolism by rat liver microsomes. Exposure of microsomes to butadiene resulted in the NADPH-dependent formation of butadiene monoxide, crotonaldehyde, 3-butene-1,2-diol, and one diastereomer of 3,4-epoxybutane-1,2-diol.