Dichlorophenoxyacetic acid anchored on silica-gel modified carbon paste for the determination of pesticide 2,4-D

Resumo

2,4-dichlorophexoyacetic acid was attached onto silica gel. For this immobilization, in the first step, 3-aminopropyltrimethoxysilane was attached onto silica gel surface in order to produce the precursor silica. The 2,4-dichlorophexoyacetic acid was incorporated onto precursor silica by reaction between chloride of 2,4-dichlorophexoyacetic acid and amine group precursor silica, forming a covalent bond of between 2,4-dichlorophexoyacetic acid to and the inorganic surface, resulting in the production of SiD material. Then, 1.02 mmol of 2,4-dichlorophexoyacetic acid per gram of silica exhibited a surface area of 250 m2/g. Infrared and 29Si NMR spectra were in agreement with the proposed structure of the modified silica. This modified silica was applied to develop a chemical carbon paste electrode to determine pesticide 2,4-D in water. Voltammetric studies showed that the 2,4-D electrochemical reduction involved 4 electrons for each 2,4-D molecule reduction. Detection and quantification limits of 2,4-D in water were 0.45 μmol/L.

Descrição

Palavras-chave

Dichlorophenoxyacetic acid, Chronoamperometry, Pesticide 2,4-D,carbon paste electrode, Cyclic voltammetry

Citação

PRADO, Alexandre G. S. et al. Dichlorophenoxyacetic acid anchored on silica-gel modified carbon paste for the determination of pesticide 2,4-D. International Journal of Electrochemical Science, Belgrade, v. 7, p. 8929-8939, 2012.