ANALYSIS OF DNA-ADDUCTS IN DNA HYDROLYSATES BY CAPILLARY ZONE ELECTROPHORESIS AND CAPILLARY ZONE ELECTROPHORESIS ELECTROSPRAY MASS-SPECTROMETRY

The in vitro adduct formation with phenyl glycidyl ethers (PGEs) was s tudied on 2'-deoxynucleotides and DNA. The modified DNA was hydrolyzed enzymatically and the mixtures consisting of unmodified and modified 2'-deoxynucleotide adducts were analyzed by capillary zone electrophor esis (CZE), CZE-electrospray mass spectrometry (CZE/ES-MS) and CZE-ele ctrospray tandem mass spectrometry (CZE/ES-MS/MS) using sample stackin g, For the CZE analyses, a homemade system was developed in order to e nhance the reproducibility of the retention times. This modification e nabled the total comparison of the electropherograms obtained for the analysis of 2'-deoxynucleotides mixtures with the electropherograms ob tained for the DNA hydrolysates both treated with PGEs, The assignment of adducted and nonadducted 2'-deoxynucleotide peaks was unambiguous. Analysis of the CZE/ES-MS data gave the necessary structural informat ion and revealed the presence of mono- and dialkylated 2'-deoxynucleot ides. Interpretation of the CZE/ES-MS/MS data of the monoalkylated pro ducts allowed differentiation between purine or pyrimidine alkylation and alkylation of the 5'-phosphate moiety. Recording of full-scan mass spectra during CZE/ES-MS/MS analysis of 2'deoxynucleotide reaction mi xtures and DNA hydrolysates was possible, using the described CZE samp le stacking technique.