Modification of screen-printed carbon electrode for detection of pesticides

Abstract

Methyl parathion (MP) is an organophosphate pesticide broadly used in agriculture to protect crops and fruits from the damages caused by insects and pests. However, when it is used in large quantities, it can be potentially toxic to humans and animals, causing many poisoning effects. Moreover, its residues can also penetrate the food chain (via agriculture food products) as well as contaminating the environment, leading to air, water and soil pollution. Therefore, rapid determination and reliable quantification of trace level of MP are crucially needed for food safety and environmental monitoring. In this work, a low-cost and portable electrochemical sensor was simply developed using a screen-printed carbon electrode (SPCE) for determination of MP residues with enhanced sensitivity. Typically, the SPCEs fabricated in-house was modified with polyaniline (PANI) using electro-polymerization technique, followed by the electrodeposition of gold nanoparticles (AuNPs), to obtain the AuNPs/PANI/SPCE sensor for MP detection. The modified AuNPs with electrocatalytic activity could increase the electrochemical performance of the detection, while the characteristics of PANI could make the sensor more conductive. The determination of MP was thoroughly investigated using the modified electrode by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under optimal conditions, the AuNPs/PANI/SPCE showed high sensitivity, good stability, and reproducibility with acceptable limit of detection (LOD). The proposed AuNPs/PANI/SPCE sensor could then be applied for MP detection in real samples with satisfactory recoveries (107.30% - 110.83%).