Cobalt phthalocyanine as a biomimetic catalyst in the amperometric quantification of dipyrone using FIA

Abstract

A biomimetic sensor for the determination of dipyrone was prepared by modifying carbon paste with cobalt phthalocyanine (CoPc), and used as an amperometric detector in a flow injection analysis (FIA) system. The results of cyclic voltammetry experiments suggested that CoPc behaved as a biomimetic catalyst in the electrocatalytic oxidation of dipyrone, which involved the transfer of one electron. The optimized FIA procedure employed a flow rate of 1.5mLmin−1, a 75μL sample loop, a 0.1molL−1 phosphate buffer carrier solution at pH 7.0 and amperometric detection at a potential of 0.3V vs. Ag/AgCl. Under these conditions, the proposed method showed a linear response for dipyrone concentrations in the range 5.0×10−6–6.3×10−3molL−1. Selectivity and interference studies were carried out in order to validate the system for use with pharmaceutical and environmental samples. In addition to being environmentally friendly, the proposed method is a sensitive and selective analytical tool for the determination of dipyrone.