Determination of urinary 8-hydroxy-2′-deoxyguanosine by capillary electrophoresis with molecularly imprinted monolith in-tube solid phase microextraction

Urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) is an excellent marker of oxidative DNA damage. In this study, employing guanosine as dummy template a novel molecularly imprinted (MIP) monolithic capillary column had been synthesized, and that was used as medium of in-tube solid phase microextraction (SPME). Coupled with capillary electrophoresis-electrochemical detection (CE-ECD), the system of extraction and detection of 8-OHdG in urinary sample had been developed. Because of its greater phase ratio combined with convective mass transfer and inherent selectivity, the MIP monolithic column exhibited high extraction efficiency on target analyte with the limit of detection (LOD) and quantity (LOQ) reached 2.6 nmol/L (S/N = 3) and 8.6 nmol/L (S/N = 10), respectively. The linear range was from 10 nmol/L to 1.5 μmol/L (r = 0.9999) with relative standard deviation (RSD) 3.7% for peak current, and 0.5% for migration time, and the average recovery of spiked 20–200 nmol/L 8-OHdG was 85% ± 3.5% (n = 6). This highly sensitive method was applied to analysis of 8-OHdG in urinary samples from healthy volunteers, coking plant workers and lung cancer patients.