Accumulation and trace measurement of paraquat at kaolin-modified carbon paste electrode

The carbon paste electrode modified by kaolin (KCPE) has been utilized for the determination of pesticides with high sensitivity based on their redox behavior. The experiment is performed on the use of cyclic and square wave voltammetry. Experimental conditions were optimized by varying the accumulation time, kaolin loading and measuring solution pH. Square wave voltammetric response showed a linear calibration curve in the range from 3.9x10(-9) to 9x10(-5) mol L-1 with a detection limit of 2x10(-10) mol L-1 at kaolin-modified carbon paste electrode. As a result, it was found that there was feasibility in the use of kaolin to improve the carbon paste electrode properties. (C) 2010 Elsevier B.V. All rights reserved.