Quantitation of etheno adducts by fluorescence detection

Etheno adducts can be formed by the reaction of vinyl chloride metabolites with DNA and may play a role in the carcinogenicity of this chemical. These adducts are highly fluorescent and may be quantitated by sensitive photometric methods in conjunction with high-performance liquid chromatographic (HPLC) separation. Three HPLC systems were evaluated on the basis of maximal fluorescence intensity and resolution of two etheno adducts, ethenodeoxycytidine and ethenodeoxyadenosine. Analyses were conducted with enzymatically digested DNA that had been incubated with chloroacetaldehyde, a vinyl chloride metabolite which may cause etheno adduct formation in vivo. All three known etheno adducts of DNA were tentatively identified in DNA reacted in vitro. The sensitivity of the method was highest for the ethenodeoxyadenosine adduct, with the limit of detection (1 pmol per injection in the HPLC system) being similar to that for O6-methylguanine, another promutagenic DNA adduct for which quantitation by HPLC with fluorescence detection has been reported. The method described here may be useful for the analysis of DNA from animals or humans exposed to vinyl chloride.