A system consisting of cation-exchange chromatography, combined surface-activated chemical and electrospray ionization, and ion-trap analysis for the analysis of 8-oxo-7,8-dihydro-2′-deoxyguanosine in urine

RATIONALE: 8-Hydroxy-2'-deoxyguanosine has served as a biomarker for oxidative damage to DNA from different types of biological samples, and various techniques have been used to analyze it. In particular, liquid chromatography coupled to mass spectrometry has been used to identify 8-hydroxy-2'-deoxyguanosine in urine samples. Usually, a triple quadrupole analyzer and multiple reaction monitoring have been employed for its detection. Only a few studies have used a less expensive ion-trap analyzer instead. METHODS: We have developed a new liquid chromatography/mass spectrometry procedure that incorporates cation exchange chromatography in conjunction with surface-activated and electrospray ionization with an ion trap analyzer for the mass spectral step. RESULTS: The combination of two ionization sources reduced the matrix effect arising from in-source reactions, thus increasing the sensitivity to levels comparable with those obtained by triple quadrupole analyzers. CONCLUSIONS: This new method for 8-hydroxy-2'-deoxyguanosine detection provided increased sensitivity and reduced chemical noise, using a less expensive, stable and accurate mass spectrometric technology. Copyright (C) 2011 John Wiley & Sons, Ltd.