Self-standing block shaped cobalt metal organic frameworks deposited graphite rod electrode for non-enzymatic electrochemical detection of imidacloprid in vegetable and fruit

Neonicotinoid pesticides are increasingly being used in agriculture and farming sectors, which can have hostile effects on the environment and water resources. All living creatures including humans had forcefully consumed from the environment this cancerous neonicotinoid pesticide, imidacloprid. Herein, our study reported a novel free-standing electrochemical sensor for ultrasensitive and discriminatory detection of imidacloprid (IM) pesticide using cobalt metal-organic framework (MOF) anchored graphite rod (GR). The surface structure and morphology of the porous Co(pyrazole dicarboxylic acid)[PZDA]MOFs were systematically investigated after solvothermal growth on graphite rods. Electrochemical experiments revealed noteworthy catalytic activity for Co(PZDA)MOF//GR in reducing imidacloprid. The synergistic effect between GRs and Co(PZDA)MOF significantly improves the electrochemical responses. Electrocatalysis studies displayed reversible diffusion-controlled kinetics of four electrons and four protons involved in the electro-reduction of imidacloprid. Detection of IM by differential pulse voltammetry (DPV) method portrays a wide lined dynamic range (0.01 – 100 µM) with a sensitivity of 83.69 μA μM−1 cm−2 and limit of detection value 4.8 nM. Moreover, Co(PZDA)MOF//GR electrode showed an unique electrocatalytic performance and excellent duplicability, outstanding repeatability, and brilliant storing steadiness up to two months. Thus, the sensor electrode provides a simple, affordable, environmentally friendly, cost-effective imidacloprid detection tool in real-world samples.