Reinaldo F. Teófilo1, Efraim L. Reis1,*, César Reis1, Gilmare A. da Silva1, José F. Paiva2 and Lauro T. Kubota3
1 Departamento de Química, Universidade Federal de Viçosa, UFV, 36570-000, Viçosa, MG, Brasil
2 Departamento de Química, Universidade Federal de Ouro Preto, UFOP, 35400-000, Ouro Preto, MG, Brasil
3Instituto de Química, Universidade Estadual de Campinas, UNICAMP, 13084-971, Campinas, SP, Brasil
Received 13th November 2007; accepted 19th April 2008
Abstract
]]> A voltammetric procedure optimized by experimental design for glyphosate determination in soil, water and vegetable samples is described. The voltammetry experiments were performed using a hanging mercury drop electrode (HMDE). The DPV variables involved in the optimization process were: voltage step, pulse amplitude, pulse interval, voltage step time and concentration of the supporting electrolyte. A full 25 factorial design was chosen to evaluate these effects. From the results obtained by the factorial design the three most important factors were determined. These variables were evaluated with a central composite design. Under the optimized conditions, the operational range was from 0.050 to 100.0 mg dm-3 and the detection and quantification limits were 14 and 48 µg dm-3, respectively. The optimized method was successfully applied to glyphosate determination in soil, water and vegetables after purifying with an ion exchange resin and derivation.
Keywords: glyphosate, SWV, experimental design, voltammetry.
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* Corresponding author. E-mail address: efraim@ufv.br
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