Silver nanoparticles incorporated local montmorillonite clay modified carbon paste electrode for the voltammetric determination of Arsenic (III) in aqueous solution

Abstract

A sensitive electrochemical method was developed to determine arsenic (III) using silver nanoparticles incorporated local montmorillonite clay nanocomposites modified carbon paste electrode (Ag-NPs/MT/CPE) in aqueous solution. Electrochemical properties of carbon paste electrode (CPE) modified by Ag-NPs/MT nanocomposite were studied using cyclic voltammetry and electrochemical impedance spectroscopy in the presence of 10 mM K₃Fe(CN)₆ ^3-/4-/0.1 M KCl aqueous solution as well as in the presence of 100 μg/mL As (III) in 0.1 M PBS. Voltammograms acquired on Ag-NPs/MT/CPE showed an enhancement of the oxidation current density peak compared to the bare CPE. This is attributed mainly to the catalytic activity and improved surface to volume ratio of Ag-NPs/MT composite. The electrochemical sensor based on Ag-NPs/MT nanocomposite was constructed and used for the detection of As (III). Under optimized condition (pH 7, deposition potential-0.3 V and deposition time 60 s) the sensor exhibits sensitivity 0.02953µA/µg/mL and detection limit 38.2 µg/mL As (III). The Ag-NPs/MT/CPE has also shown good stability, it retained a response of 93.8% of the initial current after 12 days storage at room temperature. Therefore, the developed sensor can be a good candidate for electrochemical determination of As (III) in aqueous solution.