Fabrication of spinel magnesium stannate-polyaniline nanocomposite for electrochemical detection of fenitrothion pesticide and supercapacitor applications

• Avocado seed extract is used as a green reducing agent for synthesis of Mg2SnO4/PANI. • Enhanced electrochemical performance of MSO/PANI composite compared to MSO and PANI. • Low LOD (0.04 nM) with wide linear range (0.01 to 390 µM) of fenitrothion detection using MSO/APNI@GCE. • Good recovery of FNT in grapes and river water. • SMSO/PANI showed a specific capacitance of 695 F g-1 at a scan rate of 10 mV s⁻¹. Fenitrothion (FNT), a commonly used organophosphorus pesticide used in agriculture poses numerous health hazards to living beings and the environment. Therefore, monitoring the dosage of FNT in agriculture is becoming increasingly important. The current work aims to develop an electrochemical sensor for the sensitive detection of FNT. A simple green method using avocado seed extract as a reducing agent has been developed for the synthesis of spinel-structured Mg 2 SnO 4 (MSO), which is combined with polyaniline (PANI) to generate the MSO/PANI nanocomposite. Glassy carbon electrode (GCE) was modified using MSO, PANI and MSO/PANI were examined for electrochemical performance using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. Superior electrochemical performance is observed in MSO/PANI-modified GCE compared to MSO and PANI-modified GCE. Superior activity in MSO/PANI could be attributed to the improved electroactive sites, conductivity, and easy electron exchange at the electron/electrode system. FNT detection was carried out using different electrodes and found to show a wide range of detection (0.01 to 390 µM) using DPV with a 0.04 nM limit of detection (LOD). FNT detection was pursued in the presence of grapes and river water and the percentage recovery is in between 97.1 to 99.1. MSO/PANI has been used as electrode material and found to exhibit specific capacitance of 695 F g -1 at a scan rate of 10 mV s⁻¹. Good recyclability, superior performance, stability, and real sample performance make MSO/PANI a material of choice towards electrochemical performance as a sensor and supercapacitor and serve towards sustainability towards the environment, health, and energy.