Voltammetric Study of Ascorbic Acid Using Polymelamine/Gold Nanoparticle Modified Carbon Paste Electrode

Polymelamine/gold nanoparticle modified carbon paste electrode (PM/AuNPs/CPE) has been developed for voltammetric study of ascorbic acid (AA). The PM/CPE was prepared onto carbon paste electrode surface via electropolymerization, then it has been deposited gold nanoparticle (AuNPs) via electrodeposition for PM/AuNPs/CPE. In pH 7.0 phosphate buffer, PM/AuNPs/CPE was oxidized during the cyclic potential sweep between 0.0 V and 1.5 V, forming polymer and gold nanoparticle at the carbon paste electrode (CPE) surface. The electrochemical behavior of ascorbic acid at the bare CPE, PM/CPE, AuNPs/CPE and PM/AuNPs/CPE were investigated. The oxidation peak potential of ascorbic acid shifts to more negative potential at PM/AuNPs/CPE Moreover, the oxidation peak current significantly increases at PM/AuNPs/CPE. The PM/AuNPs/CPE electrode exhibits a quasi-reversible electron with a peak separation 130 mV. These fenomena indicate that PM/AuNPs/CPE shows highly-efficient catalytic activity to the oxidation of ascorbic acid. (paper)