Nano-perovskite carbon paste composite electrode for the simultaneous determination of dopamine, ascorbic acid and uric acid

Abstract

A perovskite, SrPdO3, of the type ABO3 was used in the form of a composite with carbon paste as an electrode (CpE/SrPdO3) for the electrochemical sensing of dopamine (DA) in biological fluids. The CpE/SrPdO3 electrode showed a unique long term stability and low detection limit for (DA) determination. The structural characteristics of the modifier (SrPdO3) that were prepared by a green method revealed a primary orthorhombic perovskite phase of SrPdO3 and a secondary phase of SrPd3O4. The electrocatalytic activity of the CpE/SrPdO3 electrode toward DA oxidation is relatively higher when compared to electrodeposited palladium nanoparticles modified CpE (CpE/Pd) with equivalent loading of Pd4+ salt. The prepared perovskite was characterized by XRD and SEM. Electrochemical characterization of CpE/SrPdO3 was done using cyclic voltammetry, differential pulse voltammetry and electrochemical impedance spectroscopy. The redox behavior of DA follows a quasi reversible mechanism and two linear ranges of 7–70μmolL−1 and 90–160μmolL−1 with low detection limits of 9.3nmolL−1 and 25nmolL−1, respectively, and good correlation coefficient of 0.9981 could be determined. The electrocatalytic behavior is explained in terms of an oxygen–surface interaction between the oxygen atoms of the hydroxyl groups and the transition element in the perovskite. The protocol of DA sensing using this method was simple, sensitive and successfully applied for direct determination of DA in human urine samples with excellent recovery results. CpE/SrPdO3 showed also high reproducibility, enhanced sensitivity, selectivity and anti-interference ability.