Evaluation of the oxidative deoxyribonucleic acid damage biomarker 8-hydroxy-2'-deoxyguanosine in the urine of leukemic children by micellar electrokinetic capillary chromatography.

Determining the level of urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG), an oxidative DNA damage biomarker, is vital to the study of clinical pathogenesis and drug toxicity. The principal limitation of capillary electrophoresis (CE) with UV detection is its low sensitivity. To overcome this shortcoming, we developed a micellar electrokinetic capillary chromatography (MEKC) with solid-phase extraction (SPE) for urinary 8-OHdG analysis. The sensitivity of MEKC-UV was improved using a reasonable UV system, injection mode, and SPE. The parameters affecting MEKC and SPE were also optimized. The calibration curve was linear within the range from 1 to 500 μg L(-1). The limits of detection and quantification were 0.27 μg L(-1) and 0.82 μg L(-1), respectively. Interday and intraday precision were both <5.6%. The recovery of 8-OHdG in urine ranged from 94.5% to 103.2%. This method was used to measure urinary 8-OHdG from eight normal children, eight newly diagnosed leukemic children, and eight leukemic children undergoing chemotherapy. The results show that the proposed method can be used to assess oxidative stress in patients and the side effects of chemotherapeutic drugs by measuring urinary 8-OHdG.