Using one step solid-phase extraction for urine pretreatment and a new sample focusing mode-dynamic pH junction injection for increasing sensitivity, a simple and sensitive method for the analysis of urinary 8OHdG by capillary electrophoresis with end-column amprometric detection has been developed. The limit of detection was 20 nmol/L(signal to noise ratio S/N=3). The urinary concentration of 8OHdG in nine healthy persons and 28 cancer patients was determined. It was found that urinary concentration of 8OHdG in cancer patients was significantly higher than that in healthy persons[(35.26±27.96) nmol/L) vs. (13.51±5.08) nmol/L, P<0.05], the result demonstrated that 8OHdG may be a good biomarker for measurement of oxidative DNA damage in cancer patients. Furthermore, the excretion levels of urinary 8OHdG from cancer patients receiving surgical therapy are investigated, and the results demonstrated that the smoking has a strong effect on 8OHdG content.
