USE OF COBALT(II) PHTHALOCYANINE TO IMPROVE THE SENSITIVITY AND STABILITY OF GLASSY-CARBON ELECTRODES FOR THE DETECTION OF CRESOLS, CHLOROPHENOLS AND PHENOL

A cobalt(II) phthalocyanine-modified glassy carbon electrode (CoPc-GCE ) was used for the detection of o-, In-and p-cresols, and of 2-chlorop henol, 4-chlorophenol and phenol. Modification of the glassy carbon el ectrode with CoPc increases the oxidation currents of these species an d increases the stability of the electrode. CoPc-GCE showed less fouli ng by the oxidation products of these compounds than the unmodified GC E. Comparison of some first row transition metal phthalocyanines showe d the following trend for the enhancement of the currents for he oxida tion of cresols and phenols: Co(II)Pc>Mn(II)Pc>Fe(II)Pc>Ni(II)Pc>Cu(II )Pc >H2Pc>Zn(II)Pc>GCE. When [Co(II)TSPc](4-)(TSPc=tetrasulfo Pc) was added to aqueous solutions containing the cresols and phenols, an enha ncement of the oxidation currents was also observed. (C) 1997 Elsevier Science B.V.