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Quantificação do pesticida diclorvos por voltametria de onda quadrada em águas puras e naturais

2004; Brazilian Chemical Society; Volume: 27; Issue: 6 Linguagem: Inglês

10.1590/s0100-40422004000600014

1678-7064

R.T.S. Oliveira, Sérgio Antônio Spínola Machado,

Water Quality Monitoring and Analysis

WATERS.This work reports the use of square wave voltammetry (SWV) to analyse the electrochemical reduction of dichlorvos (2, 2-dichlorovinyl-dimethylphosphate) in spiked pure and natural waters.SWV measurements were carried out in 0.5 mol L -1 Na 2 SO 4 aqueous solutions at pH 5, prepared with water originated from three different sources, namely, one sample of purified water and others from two urban creeks in São Carlos County.In all cases, two reduction peaks were observed, at potentials of -0.15 and -1.05 V vs Ag/AgCl, with both current and potential being dependent on pesticide concentration.This allowed the calculation of the following detection limits: 1.0, 2.5 and 3.0x10 -8 mol L -1 for purified, Gregorio creek and Monjolinho creek waters, respectively, in a working range between 2.0x10 -7 and 1.4x10 -6 mol L -1 .Recovery measurements found values higher than 80% in all cases, for an added concentration of 4.0 x 10 -7 mol L -1 of dichlorvos in each solution.All analytical experiments were performed in triplicate and showed a standard deviation always less than 3%.