Two-Dimensional UHPLC-MS/MS Determination of 8-Hydroxydeoxyguanosine in Urine

After centrifugation, the urine sample was purified with WATERS C₁₈ solid phase extraction column, and then the eluate was collected. Two-dimensional UHPLC-MS/MS was applied to the determination of 8-hydroxydeoxyguanosine in the sample solution. Waters BEH C₁₈ chromatographic column (for one-dimensional chromatography) and Waters BEH HILIC chromatographic column (for two-dimensional chromatography) were used as stationary phase. The mixture of 0.1% (φ, the same below) formic acid solution and acetonitrile with volume ratio of 8∶2 (for one-dimensional chromatography) and the mixture of 0.1% formic acid solution and acetonitrile with volume ratio of 9∶1 (for two-dimensional chromatography) were used as mobile phase. ESI⁺ and multi-reactions monitor mode were adopted in MS/MS. Internal standard method was used for quantitative. Linearity range of 8-hydroxydeoxyguanosine was found in the range of 0.25-300.0 ng·g^-1 with detection limit (3S/N) of 0.10 ng·g^-1. On the matrix of blank sample, test for recovery was made by standard addition method; values of recovery found were in the range of 96.6%-103%, with intra-day RSDs (n=6) and inter-day RSDs (n=4) of determined values in the ranges of 0.87%-3.3% and 1.9%-4.9% respectively.