Electropolymerization of Metallophthalocyanines Carrying Redox Active Metal Centers and their Electrochemical Pesticide Sensing Application

Abstract

In this study, modified electrodes were constructed with the electropolymerization of metallophthalocyanines (MPcs) carrying redox active metal cations and electropolymerizable substituents. Then these electrodes were tested as selective and sensitive electrochemical pesticide sensors. Incorporation of the redox active Co(II) (CoPc(MOR-NAF)), Cl-Mn(III) (MnPc(MOR-NAF)), and Ti(IV)O (TiOPc(MOR-NAF)) metal cations into Pc cavity increased the redox activity of Pc ring. Moreover, redox active and electropolymerizable 5-{[(1E)-(4-morpholin-4-ylphenyl)methylene]amino}-1-naphthoxy substituents (MOR-NAF) on the Pc ring triggered coating of the complexes on the electrode surface with the electropolymerization reactions. Therefore, modified electrodes GCE/MPc(MOR-NAF) were constructed with the electropolymerizations of MPcs. These electrodes illustrated reasonable redox activity and conductivity for the potential applications in different fields of the electrochemical technologies. Pesticide sensing measurements indicated that changing the metal center of the complexes significantly altered their sensing activities. Among the complexes, GCE/CoPc(MOR-NAF) electrode behaved as the most sensitive and selective electrode and it sensed the parathion with good selectivity and sensitivity. GCE/CoPc(MOR-NAF) electrode showed a wider linear range (0.075-5.75 moldm(-3)) and smaller LOD (0.025 moldm(-3)) and higher sensitivity (3.46 Acm(-2)M(-1)) for the parathion sensing. Although GCE/TiOPc(MOR-NAF) electrode also sensed the parathion with a high sensitivity, its selectivity was poor and the linear range of this sensing was very narrow. Differently GCE/Cl-MnPc(MOR-NAF) electrode only sensed eserine with reasonably sensitivity.