Electrochemistry of 2,6-diaminopurine on multiwall carbon nanotube modified glassy carbon electrode

The electrochemical oxidation of 2,6-diaminopurine (2,6-DAP) was studied in pH 7.4 phosphate buffer solution on multiwall carbon nanotube modied glassy carbon electrode (MWCNT/GCE) over a temperature range of 20 to 50°C using cyclic voltammetry. 2,6-DAP oxidation on MWCNT/GCE showed a well-dened and irreversible oxidation peak at about 0.72 V vs. Ag/AgCl at pH 7.4. The oxidation potential of 2,6-DAP linearly varied with pH over the range of 3.0 to 10.0 with a slope of {0.0547 V/pH, implying that 2 protons were accompanied by 2 electrons transferred in the electrochemical reaction. The activation energy, Ea, of oxidation reaction was found to be 33.10± 1.88 kJ/mol. The differential pulse voltammetric determination of 2,6-DAP was also studied. The peak currents increased linearly with increasing of the 2,6-DAP concentration range from 0.4 μmol/L to 80 μmol/L. The linear regression equation appeared as I p /μA = {(1.66 ± 0.42) + (4.21± 0.11) [2,6-DAP]/μmol/L, R^2 = 0.9982, and the detection limit (S/N = 3) was 3 * 10^-7 ± 0.015 mol/L (n =3). The electrocatalytic oxidation of 2,6-DAP on MWCNT/GCE showed that acid pretreated multiwall carbon nanotube can be used in new applications in electrochemical determinations of biologically important compounds.