Resumo

LUNA, José Rafael et al. Determination of paraquat in urine samples by flow-injection analysis. Acta bioquím. clín. latinoam. [online]. 2008, vol.42, n.2, pp.251-259. ISSN 0325-2957.

Paraguat is a herbicide beloging to the bipyridinium group.The quantitative determination of paraquat in urine of humans is very important to diagnose survival of intoxicated patients. Many hospitals use semi-quantitative tests for determining paraquat in biological samples. However, they often lack precision and accuracy. Therefore, the development of simple, precise, accurate and accessible alternative methods could be very useful in hospital institutions. Based on these considerations, a flow-injection spectrophotometric procedure is proposed for paraquat determination in urine samples. The determination is based on the formation of a coloured product (600 nm) after on-line reduction of paraquat with glucose in alkaline medium. Under optimal conditions of operation, Beer's law is obeyed in a concentration range of 1-50 µg mL^-1 of paraquat with a correlation coefficient >0.999. The analytical frequency was 12 h-1 and the relative standard deviation was 2.8% for a sample solution containing 10 µg mL^-1 paraquat (n=3). Recovery studies were between 97.9 and 102.1%. The analytical method was satisfactorily applied in the analyses of samples from two intoxicated patients.

Palavras-chave : Paraquat; Flow injection analysis; Urine; Glucose.

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