Electrochemiluminescence detection of dichlorvos pesticide in luminol-CTAB medium

A simple, novel electrochemiluminescence (ECL) method for the detection of dichlorvos pesticide (DDVP) with high sensitivity was discovered. Detection was carried out in a static ECL system, in which a glassy carbon electrode was selected as the working electrode. ECL parameters, including the concentrations of cetyrltrimethylammonium bromide and luminol. the solution pH, and the scan rate of the applied potential, were optimized. Under these optimal conditions, the linear response of ECL-emission versus DDVP concentration was valid in the range 5-8000 ng/L (r(2) = 0.9982) with a relative standard deviation of 4.3% at 2000 ng/L(n = 10), yielding a detection limit (S/N = 3) of 0.42 ng/L. The ECL emission was caused by a radical reaction process, in which the dissolved oxygen in the luminol solution reacted with the DDVP and generated free radicals. The free radicals reacted with the luminol anion and yielded the luminol radical. The approach presented was successfully applied to the determination of DDVP residues in vegetable samples. (C) 2008 Elsevier B.V. All rights reserved.