Characterization and Application of Carbon Paste Electrode Modified by Moringa Oleifera Seed Powder to the Electrochemical Detection of Mercury

Abstract

Heavy metal pollution of surface waters from anthropogenic activities is constantly increasing. Monitoring techniques must therefore be more precise and more sensitive. One of the effective methods available is the development of sensitive electrochemical sensors, dedicated to the analysis of pollutants in aqueous solution. The carbon paste electrode (CPE) in this study was modified with Moringa Oleifera seed powder, a flocculant-adsorbent used to treat water. This chemically modified electrode presented improved electrochemical reactivity in cyclic votammetry towards the redox marker Ferri / Ferrocyanide compared to the bare carbon paste electrode. The 10 % modifier presented the most interest during the analysis. The Modified electrode was used to detect mercury (II) in anodic stripping voltammetry. The detection current of mercury (II) is seven times that of carbon paste electrode (CPE). The calibration curve is linear in the range from 0.002 μmol/L to 0.009 μmol/L (0.4 μg/L to 1.8 μg/L) with a detection limit of 0.4 ηmol/L (i.e.0.08 μg/L). This new technique can be used for routine monitoring of real aqueous matrices.