Detection and Identification of Benzo[a]pyrene Diol Epoxide Adducts to DNA Utilizing Capillary Electrophoresis-Electrospray Mass Spectrometry

Abstract

Capillary zone electrophoresis (CZE) coupled with negative ion electrospray mass spectrometry (ES-MS) is used for the detection and identification of adducts formed from the reaction of DNA with (±)-anti-7,8,9,10-tetrahydrobenzo[a]pyrene-7,8-diol 9,10-epoxide (BPDE), an active metabolite of benzo[a]pyrene (BaP). Results presented in this paper demonstrate low nanogram detection limits (-⁸ M). Nucleotide adducts are negatively charged at most pHs and are therefore ideally suited to the stacking process used in this research. These techniques have been applied to the analysis of the adducts formed from the in vitro reaction of BPDE with DNA. In addition it is shown that CZE-ES-MS, combined with solid-phase sample cleanup, can detect adducts at levels of four adducts in 10⁷ unmodified bases or less.