Silver particles-modified carbon paste electrodes for differential pulse voltammetric determination of paraquat in ambient water samples

Abstract

This paper describes the construction of silver particles-impregnated carbon paste electrode (Ag-CPE). The new electrode revealed an interesting determination of paraquat (II). The latter was accumulated on the modified electrode surface by adsorption onto silver particles and was reduced in 0.1 mol L1 of Na2SO4 electrolyte at 0.70 V and 1.0 V for peaks 1 and 2, respectively. Experimental conditions were optimized by varying the heating temperature of the silver/carbon composite, the Ag/CP ratio, pH of measuring solution and accumulation time. Under the optimized working conditions, calibration graphs were linear for the concentration ranging from 1.0 · 107 to 1.0 · 103 mol L1 with detection limits (DL, 3r) 3.3 and 6.4 · 109 mol L1 , respectively, for peaks 1 and 2. The precision of this methodology was evaluated for eight successive measurements of the same samples containing 1.0 · 104 mol L1 of paraquat. The relative standard deviations (D.S.R.) were 1.9% and 2.4% for the peaks 1 and 2, respectively. The Ag/CP composite was characterized by X-ray diffraction (XRD) and BET adsorption analysis. ª 2014 P