LC-APCI-MS/MS analysis of urinary 8-hydroxy-2'-deoxyguanosine.

8-Hydroxy-2'-deoxyguanosine (8OHdG) is regarded as an important biomarker of oxidative DNA damage and it may be estimated by using different techniques in various biological matrices, most notably DNA and urine. In the case of DNA, artifactual oxidation may take place during the isolation of DNA, its hydrolysis and possible derivatization (as for GC-MS), invalidating the measurement of 8OHdG. Therefore, the direct analysis of 8OHdG excreted into urine was preferred. Interferences from the urine matrix were excluded by applying LC-APCI-MS/MS in the multiple reaction monitoring (MRM) mode. The abundant fragment ion at m/z 168 arising from 8OHdG was monitored in the urine sample of volunteers supplemented with tomato concentrate for different times. The procedure allowed the detection of levels of 8OHdG as low as 1 ng/ml in urine sample.