Indirect determination of the pesticide dimethoxydithiophosphate in an FIA-AAS system with liquid-liquid back-extraction.
A method has been developed for the determination of dimethoxydithiophosphate (DDTP) by liquid-liquid extraction in a flow-injection analysis (FIA) system with detection by atomic-absorption spectrometry (AAS). It is based on the formation of the Cu(DDTP)(2) complex and its extraction into chloroform, and back-extraction of the copper with an ammonia buffer (pH 10). The method uses small amounts of samples, avoids handling errors and is fast and highly reproducible. It features a detection limit of 0.39 ppm DDTP (2.45 x 10(-6)M in the organic phase) and a relative standard deviation of 1.6%. The method has been applied to the determination of the organophosphorus pesticide malathion in an agricultural formulation.
de Blas
O J
OJ
Department of Analytical Chemistry, Nutrition and Food Science, University of Salamanca, 37008 Salamanca, Spain.
de Paz
J L
JL
Mendez
J H
JH