Detection and quantification of N-(deoxyguanosin-8-yl)-4-aminobiphenyl adducts in human pancreas tissue using capillary liquid chromatography-microelectrospray mass spectrometry.

Cigarette smoking has been associated with various cancers including bladder and pancreas. 4-Aminobiphenyl has been isolated as a constituent of cigarette smoke and has been established as a carcinogen in various animal models and humans. In rodents and humans, 4-aminobiphenyl is N-hydroxylated and forms adducts to DNA, the predominant one being N-(deoxyguanosin-8-yl)-4-aminobiphenyl (dG-C8-ABP). In this study, we report a micro-electrospray mass spectrometric (muESI-MS) isotope dilution method for the detection and quantification of dG-C8-ABP in human pancreatic tissue. A reverse phase capillary column (320 microm ID) was connected to a triple quadrupole mass spectrometer via a commercially available micro-ESI source. The system was operated in the selected reaction monitoring mode transmitting the [M + H]+ --> [M + H - 116]+ transitions for both the analyte and the isotopically labeled internal standard. Twelve human pancreas samples were analyzed, where six were current smokers (three male and three female) and six were considered nonsmokers (three female and three male). Of the samples analyzed, six showed dG-C8-ABP levels above the limit of quantification for the method, five were considered to have levels that were undetectable, and one was discarded due to inconsistent internal standard signal. The age of the human subjects ranged from 17 to 63, and, in samples where adduct was present, levels ranged anywhere from 1 to 60/10(8) nucleotides. Although no correlation between smoking preference, age, or gender was proven with this particular sample pool, this report demonstrates that capillary LC-muESI-MS can provide a sensitive and definitive method for DNA adduct analysis in human tissue.