Sensitive voltammetric sensor for the determination of oxidative DNA damage in calf thymus DNA

A simple and reliable method based on voltammetry is proposed for the determination of oxidative DNA damage by the simultaneous determination of guanine and 8-hydroxygunine using single-walled carbon nanotubes modified edge plane pyrolytic graphite electrode (SWNT/EPPGE). In acid-hydrolyzed calf thymus DNA, two well-defined peaks at ∼312 and ∼502 mV corresponding to the oxidation of 8-hydroxyguanine and guanine, respectively in phosphate buffer solution (PBS) of pH 7.2 were observed in square wave voltammetry. Remarkable enhancement in the oxidation peak current of both the compounds was observed along with the negative shift of peak potentials using SWNT/EPPGE as compared to bare EPPGE. The detection limits of guanine and 8-hydroxyguanine were calculated to be 0.05 × 10−9 and 0.01 × 10−9 mol L−1, respectively. The limits of quantification were found as 0.17 × 10−9 and 0.34 × 10−10 mol L−1 for guanine and 8-hydroxyguanine, respectively.