Electrochemical Sensor for Simultaneous Measurement of Nitrite and Superoxide Anion Radical Using Superoxide Dismutase-Mimetic Manganese(III) Tetrakis(1-methyl-4-pyridyl)Porphyrin on Polypyrrole Matrix

Abstract

An electrochemical highly sensitive nitrite (NO2 and superoxide anion radical (O •− 2 sensor was fabricated and developed based on an electrochemical deposition of manganese(III) tetrakis(1methyl-4-pyridyl)porphyrin (MnTMPyP) in polypyrrole (PPy) matrix on Pt electrode. The surface morphological image of MnTMPyP-PPy and PPy matrix on Pt electrode was obtained by scanning electron microscopy exhibiting microporous structure. The electrochemical behavior of the MnTMPyP-PPy-Pt electrode as sensor investigated by cyclic voltammetry revealed that the characteristic of MnTMPyP reversible redox peaks obtained at −0.12 V and −0.38 V versus Ag/AgCl respectively. The sensor electrode showed an excellent electrocatalytic nitrite oxidase and superoxide dismutase (SOD) activities. This electrochemical sensor exhibited a linear current response over the concentration range from 0.8 to 1000 M, with a detection limit of 0 8±0 03 M for NO2 and a corresponding linear range from 0.6 to 1000 M, with a detection limit of 0 6± 0 02 M for O•− 2 . In addition, the sensor displayed high sensitivity, good reproducibility and retained stability over a period of ∼4 weeks. This SOD-mimetic electrode was proved to be effective not only in detecting NO2 and O •− 2 independently but also in determining the concentrations of NO − 2 and O •− 2 simultaneously in in vitro systems.