Copper oxide anchored polyaniline modified glassy carbon electrode: A new sensor platform for the Amperometric determination of Chlorpyrifos

Abstract

This work aims to develop an electrochemical sensor platform for the estimation of the insecticide, Chlorpyrifos (CPF), using copper oxide (CuxO) anchored Polyaniline (PANI) modified glassy carbon electrode (GCE) [CuxO-PANI/GCE]. Even though both the bare and PANI modified GCEs were responsive to the pesticide, CuxO-PANI-GCE was more effective towards the detection of CPF. During the cyclic voltammetric measurements, the modified electrode shows one anodic and two cathodic peaks in the bare phosphate buffer solution (PBS) which were found to be the characteristics of CuxO. After stabilizing the peak currents by running multiple cyclic voltammograms, the pesticide was introduced into the solution, which binds with the Cu in the polymer resulting in an enhancement of the peak currents. This confirms the electrocatalytic activity of the electrode against CPF. The current values of anodic as well as cathodic peaks vary linearly in the concentration range of 1-12 µM. The regression coefficient values are 0.9903 and 0.9808 for anodic and cathodic curves respectively. Using the amperometric protocols, the sensitivity of the electrode is evaluated, and we conclude that the electrode is able to produce a linear variation in the sensitivity in the concentration range of 1-11 pM with the regression coefficient value, 0.9940. The sensitivity, limit of detection (LOD), and limit of quantification (LOQ) of the electrode against the pesticide are 0.028 µA/pM, 0.54 pM, 1.8 pM respectively. The selectivity of the electrode was evaluated in the presence of other possible interfering substances and determined that the modified electrode was selective towards the estimation of CPF. The electrode was employed for the determination of CPF in honey samples to analyse its performance in real samples.