Enzymatic determination of N-methylcarbamate pesticides at the nanomolar level by the stopped-flow technique.
A sensitive and selective kinetic enzymatic method for the determination of N-methylcarbamate pesticides is presented. It is based on their inhibitory effect on electric eel acetylcholinesterase and the use of 5,5'-dithiobis(2-nitrobenzoic) acid (DTNB) as chromogenic reagent for the thiocholine released from the acetylthiocholine iodide substrate. The fast DTNB-thiocholine reaction is monitored photometrically by the stopped-flow technique. Carbaryl, propoxur and carbofuran can be determined at concentrations in the ranges 6.5-120, 2-15 and 0.1-5.0 ng/ml, respectively, by the proposed method. An interference study was also reported.
Quintero
M C
MC
Department of Analytical Chemistry, Faculty of Sciences, University of Córdoba, 14004 Cordoba, Spain.
Silva
M
M
Pérez-Bendito
D
D