ANALYSIS OF BUTADIENE, BUTADIENE MONOXIDE, AND BUTADIENE DIOXIDE IN BLOOD BY GAS-CHROMATOGRAPHY GAS-CHROMATOGRAPHY MASS-SPECTROSCOPY

A new method was developed to quantify the levels of 1,3-butadiene (BD), butadiene monoxide (BDO), and butadiene diepoxide (BDO2) in blood. The method was based on vacuum distillation of tissues followed by analysis of the distillates using multidimensional GC/MS. Metabolites isolated from blood by vacuum distillation were condensed into a cold trap. After warming the traps to room temperature, BD and BDO were sampled from the trap vapor phase. BDO2 was extracted from the codistilled water phase using ethyl acetate. Samples were analyzed using a multidimensional GC system equipped with a custom-built interface. The method was validated by analysis of 0.75-mL aliquots of mouse blood spiked with 5.0, 3.4, and 0.55 nmol of BD, BDO, and BDO2, respectively. The recoveries of analytes were 96 +/- 18%, 125 +/- 15%, and 98 +/- 12%, respectively (mean +/- SD, n = 6). Kinetic studies indicated no loss of BDO and BDO2 in blood held at room temperature in closed containers for up to 1 h. The method was applied to blood samples from B6C3F(1) mice and Sprague-Dawley rats exposed by inhalation (nose-only) to 100 ppm BD for 4 h. Blood levels of BD and BDO in exposed rats were 4.1 +/- 1.0 and 0.10 +/- 0.06 mu M, respectively (mean +/- SD, n = 6). Levels of BDO2 were below the limits of detection (0.01 nmol/mL). Blood levels of BD, BDO, and BDO2 in mice exposed to 100 ppm BD for 4 h were 2.9 +/- 1.3, 0.38 +/- 0.14, and 0.33 +/- 0.19 mu M, respectively (mean +/- SD, n = 6). The results for BDO and BDO2 compare favorably with those previously determined by a less specific method at our Institute. Overall, the results suggest that although both rats and mice have detectable levels of BDO in their blood following similar BD exposures, only mice have detectable levels of BDO2. This metabolite may therefore be critical in explaining the marked species difference in BD toxicity. Future studies will confirm these results over a variety of time points and exposure concentrations.