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-, m- and p-cresols, and of 2-chlorophenol, 4-chlorophenol and phenol. Modification of the glassy carbon electrode with CoPc increases the oxidation currents of these species and increases the stability of the electrode. CoPc-GCE showed less fouling by the oxidation products of these compounds than the unmodified GCE. Comparison of some first row transition metal phthalocyanines showed the following trend for the enhancement of the currents for the oxidation 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 enhancement of the oxidation currents was also observed.