Electrochemical Monitoring of Trace-level Mercury in water sample using ZnO/GCE Modified Electrode

Abstract

Modification of glassy carbon electrode to electrochemically determine metal ions in water samples is of great interest these days. In this research, modified ZnO/GCE has been used to electrochemically sense mercury, which is toxic and harmful to human and aquatic life. ZnO NPs were synthesized by chemical aqueous growth procedure. Characteristic size and shape of ZnO NPs were determined by XRD and TEM whereas their elemental composition and functional group study were measured by EDX and FTIR, respectively. ZnO NPs were fabricated over GCE and electrochemical performance of modified ZnO/GCE was checked by employing cyclic voltammetry. The GCE fabricated with ZnO NPs was used to determine Hg (II) ions as a pollutant in real samples of water collected from Larkana district, Sindh, Pakistan. The linear dynamic range for mercury was found to be 1–80 µM with LOD and LOQ calculated as 0.001 µM .003 µM, respectively. The recovery percentage was obtained as; lowest 95% and highest 99% for canal water sample, while it was 92.5 to 100.2% for the samples ground water. The obtained results showed that the modified electrochemical sensor was stable for the selective detection of mercury ions even at low concentration.