Quantification of Benzo[a]pyrene-Guanine Adducts in in vitro Samples by LC Tandem Mass Spectrometry with Stable Isotope Internal Standardization

Abstract

Benzo[a]pyrene, after metabolic activation, is known as one of the most potent polycyclic aromatic hydrocarbons that cause a carcinogenic effect. When benzo[a]pyrene is activated by one-electron oxidation to its radical cation, it binds to either the C-8 or N-7 of guanine on DNA and forms depurinated adducts. A sensitive liquid chromatography/tandem mass spectrometry method coupled with a stable isotope internal standard was developed for detection and quantitative analysis of benzo[a]pyrene with DNA adducts. In vitro samples were analyzed by our method. The method provides structural confirmation of the adduct, as well as quantitative analysis with accuracy, confidence, isomeric specificity, and precision to measure biologically relevant levels in small sample sizes.

Keywords:

• Benzo[a]pyrene
• DNA adducts
• In vitro
• LC/MS/MS
• Quantification