Determination of Paraquat Dichloride from Water Samples Using Differential Pulse Cathodic Stripping Voltammetry

Resumo

Paraquat dichloride commonly used as herbicide was determined by differential pulse cathodic stripping voltammetry technique. Experimental parameters, such as pH, accumulation time, accumulation potential and initial potential were optimized. In this analysis, paraquat dichloride exhibited a well-defined tworeduction peaks at −0.35 and −0.90 V in the pH range from 2.0 to 12.0. The 0.04 mol L^–1 BR buffer at pH 2.0 was found a suitable medium for electroanalytical determination of the paraquat dichloride. Interfering ions effect was not significant. Linear calibration plots for standard solutions of paraquat dichloride were obtained in the range of 0.25 to 1.75 × 10^–6 mol L^–1. Detection limit was 3.66 × 10^–8 mol L^–1. The optimized parameters were effectively applied for the determination of commercial paraquat dichloride and in artificial samples. Artificial samples were prepared by spiking paraquat dichloride into tap water and drinking water dispenser samples. The recovery value was 90.5% in drinking water dispenser samples and 91.7% in tap water samples at the concentration range of 1.00 × 10^–6 to 1.75 × 10^–6 mol L^–1.