Nano eco-friendly voltammetric determination of pesticide, imidacloprid and its residues in thyme and guava leaves

Imidacloprid is a pesticide that belongs to neonicotinoids group that is commonly used in agriculture. Use of imidacloprid may lead to contamination of plants with its residues. In this work, a carbon paste electrode modified with synthesized chitosan nanoparticles and aluminum silicate was prepared as a new sensor for detection of imidacloprid residues in thyme and guava leaves. Upon modification of the carbon paste electrode, a linear response of imidacloprid was obtained and it was found to cover a wide range of 2 × 10−8 to 1 × 10−4 mol L−1 with good correlation coefficient (0.999). Limit of detection (LOD) was found to be 1.5 × 10−9 mol L−1 and limit of quantification (LOQ) was found to be 4.5 × 10−9 mol L−1. Modification of electrodes enhanced the method sensitivity, reproducibility, and increased linearity range of the method for determination of imidacloprid residues in thyme and guava leaves to monitor the suitable pre-harvest intervals.