Selective And Sensitive Electrochemical Detection of Trace Level Al (III) Ions in Water by Antipyrine Schiff’s Base-Modified Glassy Carbon Electrode

Abundant use of aluminum cookware and treatment of high fluoride-containing water with aluminum salts results in the discharge of aluminum ions into water bodies and food items, causing harmful effects on human health. Herein, an electrochemical sensor for sensing the Al (III) ions by modification of glassy carbon electrode (GCE) with Schiff’s base ligand as an electrocatalyst and activated charcoal as an electro-conductive material is being reported. The response is recorded via Square wave voltammetry (SWV) for the modified GCE, resulting in a characteristic peak at potential 0.4 V due to the interaction of the Al (III) ions with the electrocatalyst. The peak current intensity increases linearly in the concentration range from 0.1 – 50 µM (R² = 0.994), and the detection limit of 45 nM (S/N = 3) was calculated. DFT calculation reveals that the energy gap between the HOMO and LUMO decreases from 0.551 eV to 0.303 eV after the complexation of the ligand with the Al (III) ions indicating the stability enhancement after complex formation. Common interfering agents do not significantly change in the peak current intensity, demonstrating excellent selectivity. Spiking Al (III) ions in tap and river water checked practical applicability, which gave satisfactory recovery results.

Graphical Abstract