Showing papers by "Maria Lúcia Ribeiro published in 2004"
TL;DR: A simple method was developed for the determination of fluquinconazole, pyrimethanil, and clofentezine in whole fruit; peel; and pulp of mango, apple, and papaya.
Abstract: A simple method was developed for the determination of fluquinconazole, pyrimethanil, and clofentezine in whole fruit; peel; and pulp of mango, apple, and papaya. These compounds were extracted from fruit samples with a mixture of ethyl acetate-n-hexane (1 + 1, v/v). An aliquot (2 mL) of the extract was evaporated to near dryness under a stream of nitrogen, and the residue was dissolved with 2 mL methanol. The analysis was performed by means of liquid chromatography with ultraviolet detection at 254 nm using a gradient solvent system. The method was validated with fortified fruit samples at concentration levels of 0.05, 0.10, 0.20, and 0.50 mg/kg. Average recoveries (4-8 replicates) ranged from 80 to 95% with relative standard deviations between 3.5 and 12.7%. Detection limits ranged from 0.03 to 0.05 mg/kg for fruit pulp and 0.03 mg/kg for whole fruit. The quantitation limits ranged from 0.05 to 0.10 mg/kg for fruit pulp and 0.05 mg/kg for whole fruit. The analytical method was applied to fruit samples obtained from local markets.
7 citations
TL;DR: In this article, a rapid and sensitive method was described for the determination of clofentezine residues in apple, papaya, mango and orange, based on the extraction of the sample with a hexane:ethyl acetate mixture (1:1, v/v) and liquid chromatographic analysis using UV detection.
Abstract: A rapid and sensitive method is described for the determination of clofentezine residues in apple, papaya, mango and orange. The procedure is based on the extraction of the sample with a hexane:ethyl acetate mixture (1:1, v/v) and liquid chromatographic analysis using UV detection. Mean recoveries from 4 replicates of fortified fruit samples ranged from 81% to 96%, with coefficients of variation from 8.9% to 12.5%. The detection and quantification limits of the method were of 0.05 and 0.1 mg kg-1, respectively.
2 citations
20 Sep 2004
TL;DR: The TLPI (temperature leaching potenctial index) as mentioned in this paper is the model mais adequado for a investigacao de pesticidas em solos tropicais, e a comparacao for doze pesticidas foi efetuada, e os resultados obtidos mostram as limitacoes e as divergencias entre os mesmos, particularmente quando fatores como tipo de solo e temperatura sao computados nos calculos dos modelos.
Abstract: Varios modelos tem sido usados para avaliar a probabilidade de contaminacao de agua subterrânea. Estes modelos levam em consideracao, isoladamente ou em conjunto, as propriedades fisico-quimicas dos pesticidas e do solo e as condicoes ambientais. A aplicacao desses modelos e importante para selecionar os principios ativos que devem ser prioritariamente analisados em programas de monitoramento ambiental e tambem para o estabelecimento de indicadores ambientais. Pode-se trabalhar com modelos mais simples (screening da EPA, GUS e LIX) ou mais complexos (AF, RF e TLPI), dependendo dos parâmetros disponiveis. A comparacao destes modelos, para doze pesticidas foi efetuada, e os resultados obtidos mostram as limitacoes e as divergencias entre os mesmos, particularmente quando fatores como tipo de solo e temperatura sao computados nos calculos dos modelos. Os resultados indicam que o TLPI (temperature leaching potenctial index) e o modelo mais adequado para a investigacao de pesticidas em solos tropicais.