Use of Nano Ag/MWCNT′s/GCE in the Differential Pulse Voltammetric Determination of Chloride Ion in Water

Composite of nano-silver coated multi-wall carbon nanotubes (nano Ag/MWCNT′s) was prepared by chemical plating, and nano Ag/MWCNT′s modified GCE was prepared by adding dropwice a 1.0 g·L-1 suspensition of nano Ag/MWCNT′s in water onto surface of GCE (designated as nano Ag/MWCNT′s/GCE). Electrochemical behavior of chloride ion at the modified electrode was studied by cyclic voltammetry in a phosphate buffer supporting electrolyte of pH 6.0 in the potential range of -0.60 V to 1.0 V (vs.SCE). As shown by the experimental results, in nitrogen atmosphere, a pair of oxidation and reduction peaks was observed at 0.19 V and -0.20 V respectively. Values of oxidation peak current was decreased with the increase of chloride ion and linear relationship between the magnitude of decrease in oxidation peak current and concentration of chloride ion was obtained in the range of 8.0×10-3-0.1 mol·L-1. Based on these findings, a method for determination of chloride ion by differential pulse voltammetry was proposed. The proposed method was used in the determination of chloride ion in water, giving values of recovery in the range of 98.5%-100.3%.