ABSTRACT: The application of pesticides in agricultural production has been a point of concern. Thus, there is a need to determine the contamination of food by pesticides in order to improve product quality and reduce the toxicity and persistence of its residues in food and environment. At this work, to perform experimental procedure was necessary to determine the appropriate sampling for the fruit examined. The method "QuEChERS" was used as a sample preparation and clean-up technique for the analysis of pesticides in fruit samples. The analysis method validation was implemented on matrices of pear, apple and strawberry. The determination and quantification of pesticides was performed by GC-MS. The method validation in matrices of pear and apple had shown to be satisfactory. However, at the strawberry matrix was not obtained good results in percentages of recovery of some pesticides. It was also noted that the matrix where pesticides are analyzed is critical to the results. After method validation in different matrices, the effect of peeling the fruit was studied in the reduction of pesticide residues. It was observed by peeling the pear, the reduction of 83% of the pesticide difenylamine and 100% of the pesticide folpet and imazalil. In apple, the peeling decreased 85% of the pesticide difenylamine and 100% of the pesticides chlorpyrifos and imazalil. In brief, the analysis method is valid for the analysis of pesticides in the matrix of pear and apple. At the strawberry matrix, the percentages of recovery of some pesticides were low, so the quantification of them is affected. The peeling of fruit has proved to be effective in the reduction of pesticides.

Mestrado em Química Analítica e Controlo de Qualidade