DETECTION AND IDENTIFICATION OF BENZO[A]PYRENE DIOL EPOXIDE ADDUCTS TO DNA UTILIZING CAPILLARY ELEOTROPHORESIS ELEOTROSPRAY MASS-SPECTROMETRY

Capillary zone electrophoresis (CZE) coupled with negative ion electro spray mass spectrometry (ES-MS) is used for the detection and identifi cation of adducts formed from the reaction of DNA with -)-anti-7,8,9,1 0-tetrahydrobenzo[a]pyrene-7,8-diol 9,10-epoxide (BPDE), an active met abolite of benzo[a]pyrene (BaP). Results presented in this paper demon strate low nanogram detection limits (<10 ng or <15 pmol) for normal s can spectra and collision-induced dissociation spectra of the main nuc leotide adduct formed from this reaction. (BPDE reacts predominantly w ith the exocyclic amino group of guanine.) Exploitation of selective r eaction monitoring (SRM) produces detection limits in the low picogram range (<85 pg or <130 fmol). The application of sample stacking signi ficantly increases the concentration detection limit (to approximately 10(-8) M). Nucleotide adducts are negatively charged at most pHs and are therefore ideally suited to the stacking process used in this rese arch. These techniques have been applied to the analysis of the adduct s formed from the in vitro reaction of BPDE with DNA. In addition it i s shown that CZE-ES-MS, combined with solid-phase sample cleanup, can detect adducts at levels of four adducts in 10(7) unmodified bases or less.