Determination of ultra-trace amounts of neonicotinoid insecticide imidacloprid by cyclic and square wave voltammetric methods using pretreated glassy carbon electrode

Pesticide production and application have progressively increased worldwide during recent decades. Among these compounds, imidacloprid (IMD) is a widely used insecticide in agriculture, and more particularly to control sucking insects in crops. The aim of this work is to develop rapid, simple and sufficiently sensitive cyclic voltammetry (CV) and square wave voltammetry (SWV) for the detection and quantification of this insecticide in water and agriculture samples. Pretreated glassy carbon electrode (PGC) was employed as working electrode. Aqueous solutions were prepared with Confidor 200-SL commercial formulation of IMD. Each voltammogram was characterized by a well-defined single irreversible cathodic peak at approximately -1.38 V/SCE. The electrode reaction is mainly a diffusion controlled process. The optimization of experimental parameters such as IMD initial concentration, potential scan rate, pH and temperature was carried out by CV, and then a comparative study was conducted by SWV. For the detection and quantification of IMD, the results obtained by SWV showed higher sensibility and accuracy than that by CV. The developed methods were successfully used to determine IMD in real samples, namely plum and peach juice.