Mass Spectrometric Analysis for Aristolochic Acid-Deoxyribonucleic Acid Adducts
Aristolochic acid(AA) was incubated with 2'-deoxyadenosine 5'-monophosphate(dAp) in mild acid phosphate buffer in vitro for 12 hours,using either enzymatic activation(by xanthine oxidase) or chemical activation(by zinc) to synthesize AA-DNA adducts,and the solvents were evaporated under vacuum.The AA-DNA adducts were characterized by multiple mass spectrometric techniques.Electrospray ionization/tandem mass spectrometry(ESI-MS/MS) was used for the characterization of the AA-DNA adducts.Full scan spectra were obtained in the negative ion mode and the quasi-molecular ion peaks of the AA-DNA adducts were m/z 621 and m/z 591 respectively.Crude extracts were analyzed by ESI-MSn technique to investigate structural information about the fragmentation rules of AA-DNA adducts in negative mode.Using the high accuracy mass data and isotope pattern of super high resolution Fourier transform-ion cyclotron resonance mass spectrometry(FT-ICRMS),the AA-DNA adducts were identified further.The results indicated that AA-DNA adducts were synthesized in vitro successfully.This method is a powerful tool for detection and identification of AA-DNA adducts.Compared with 32P-postlabelling analysis this method has the advantages of simple operation,rapid measurement and accurate determination.