Polycyclic aromatic hydrocarbons are an important class of chemical carcinogen to which there is potentially extensive chronic human exposure. It is generally believed that an interaction of a reactive intermediate with cellular DNA is the initial step in the induction of mutations, neoplastic cell transformation and chemical carcinogenesis. Benzo(a)pyrene, the prototypic member of this class reacts with DNA through the intermediacy of a benzo(a)pyrene-7,8-dihydrodiol 9,10-epoxide metabolite (BPDE). There is considerable interest in examining these interactions. However, such research is hindered by the low levels of DNA adduct formation (typically 1 in ten to the fifth power to 1 in ten to the ninth power bases are modified by exposure). The paper reports on a preliminary investigation of the suitability of electrospray CZE-MS for characterizing benzo(a)pyrene adducts to DNA.