Comparison of carbon screen-printed and disk electrodes in the detection of antioxidants using CoPc derivatives

Cobalt phthalocyanine (CoPc) and cobalt phthalocyanine carboxylic derivatives (CoTCPc and CoOCPc) have been used as electrocatalysts for the detection of the antioxidants vanillic acid, caffeic acid, pyrogallol, and ascorbic acid on screen-printed carbon and disk electrode surfaces. The cobalt phthalocyanines were used to detect vanillic acid (with limit of detection ranging from 1.15 mu M to 2.42 mu M at potentials of 0.55-0.88 V vs. Ag vertical bar AgCl), caffeic acid (with limit of detection ranging from 1.17 mu M to 2.20 mu M at potentials of 0.30-0.81 V vs. Ag vertical bar AgCl), pyrogallol (with limit of detection ranging from 1.16 mu M to 3.63 mu M at potentials of 0.52-0.63 V vs. Ag vertical bar AgCl), and ascorbic acid (with limit of detection ranging from 1.16 mu M to 1.58 mu M at potentials of 0.34-0.46 V vs. Ag vertical bar AgCl). The kinetic studies also demonstrate diffusion-controlled processes at the electrode surface. The SPCE electrodes have better detection properties towards vanillic acid, caffeic acid, pyrogallol while the disk electrodes had better ascorbic acid detection properties as proven by kinetic studies. Both types CoPc-influenced electrodes show 100% discrimination of the antioxidants. (C) 2012 Elsevier B.V. All rights reserved.