VOLTAMMETRIC BEHAVIORS OF DOPAMINE AND ASCORBIC-ACID AT A GLASSY-CARBON ELECTRODE ANODIZED IN 1,OMEGA-ALKANEDIOL

The voltammetric behaviors of dopamine (DA) and ascorbic acid (AA) at a glassy carbon (GC) electrode anodized in 1, omega-alkanediol were examined. On cyclic voltammetry (CV) at a 1,5-pentanediol-modified GC electrode, the electrode process of AA was totally depressed, while DA still showed an anodic peak. Although similar phenomena were observed at a GC electrode anodized in 1,3-propanediol or 1,4-butanediol, the 1,5-pentanediol-modified electrode suppressed the anodic peak of AA most strongly. The voltammetric response of DA at the modified electrode was enhanced by the presence of AA, and the extent was controllable by a proper selection of the sweep rate. Thus, the electrochemical detection of DA with high sensitivity was achieved through CV with 0.1 V s(-1) at the modified electrode by adding excess AA, while electrochemical discrimination of DA from excess AA was realized at 20 V s(-1).