Quantification of urinary etheno-DNA adducts by column-switching LC/APCI-MS/MS

Lipid peroxidation induced etheno-DNA adducts are promutagenic and have been suggested to play a causal role in the development of human cancers. Therefore, human biomonitoring of etheno-DNA adducts in urine has been suggested as a potential marker for oxidative stress-related DNA damage. For quantitative determination, a column-switching LC/APCI-MS/MS method was developed for simultaneous analysis of epsilon Ade, epsilon dC, and epsilon dA in human urine. Quantitative validation parameters (precision, within-day repeatability, and between-day reproducibility) yielded satisfactory results below 10%. Limit of quantification for epsilon Ade, epsilon dC, and epsilon dA was 5.3 fmol, 7.5 fmol, and 1.3 fmol on column, respectively. Mean urinary excretion rates of a six healthy volunteers were 45.8 pmol epsilon Ade/24 h, 96.8 pmol epsilon dC/24 h, and 18.1 pmol epsilon dA/24 h. The demonstrated levels of performance suggest a future applicability of this method to studies of cancer and other diseases related to oxidative stress in humans. To our knowledge, this is the first method described that allows simultaneous determination of epsilon Ade, epsilon dC, and epsilon dA inhuman urine samples.