Influence of Dispersing Agent on the Electroanalytical Quantification of 8-Hydroxy 2'-Deoxyguanosine or Uric Acid on a Glassy Carbon Electrode Modified with Carbon Nanotubes

In this paper we report the highly sensitive quantification of 8-hydroxy 2'-deoxyguanosine (8-OHdG) or uric acid (UA) in the presence of ascorbic acid (AA) using glassy carbon electrodes (GCE) modified with multiple-wall carbon nanotubes (CNT), dispersed in various polymers such as nafion (GCE/CNT Pnaf ),polyacrylic acid (GCE/CNT- Paa ), percoll (GCE/CNT- Prl ) and polyvinyl alcohol (GCE/CNT- Pva ). The electrocatalytic activity of CNT deposited on GCE shows a significant diminish on the AA overpotential oxidation value (257 mV); making possible the AA oxidation process separation from 8-OHdG and UA ones. Using differential pulse anodic stripping voltammetry (DPASV), the analytes were quantified. The optimum sensitivity obtained in the quantification of 8-OHdG was (3.3 {plus minus} 0.1) x 10 6 μAM -1 (r = 0.994),and for UA, (3.2 {plus minus} 0.2) x 10 6 μAM -1 (r = 0.991) on GCE/CNT Pnaf , both in the presence of 1.0 mM of AA. The detection limits for 8-OHdG and UA on GCE/CNT- Pnaf are around 13x10 -9 M.