HIGH-RESOLUTION SEPARATION AND DETECTION OF DNA ADDUCTS OF BENZO[A]PYRENE

Analysis of DNA adducts as indicators of human exposure to environmental levels of carcinogenic compounds represents an extreme challenge for trace analyses to chemists. At environmental exposure levels of benzo[a]pyrene, one can expect less than one adduct per 10(7) base pairs, or roughly 30 femtomoles of adduct per mg DNA. Microcolumn separation techniques are ideally suited for the trace analysis of DNA adducts due to the high separation efficiency, enhanced mass flow sensitivity, and ease of interfacing with highly specific and sensitive mass spectrometric detectors. This study describes the analysis of benzo[a]pyrene-adducted deoxyguanosine-5'-monophosphate with micellar electrokinetic capillary chromatographic separation followed by fluorescence detection. Alternatively, adducts can be cleaved from the DNA by treatment with acid, resulting in the formation of highly fluorescent benzo[a]pyrene tetrahydrotetrols. Analysis of the tetrahydrotetrols by either capillary zone electrophoresis or microcolumn HPLC with fluorescence detection is described, Detection limits for the benzo[a]pyrene tetrahydrotetrols with either of the aforementioned separation techniques were approximately 3 femtomoles.