Determinação de resíduos de pesticidas em alimentos por cromatografia a líquido acoplada a analisadores de espectrometria de massas

Abstract

Contamination from pesticide residues has become a major concern due to the consequences to living things and the environment. On the other hand, in relation to agribusiness, pesticide residues have become a commercial barrier in the case of exports, for example. Whereas matrices are complex and concentrations of pesticides very low, there is a need for sensitive and selective analytical methods sufficient for the indentification and quantification of these contaminants. Thus, as important as the analytical method, capable of detecting a variety of organic contaminants at the trace level, a good sample preparation procedure is also necessary. Therefore, the present work had the general objective, presented in the form of scientific articles: to address the use of high resolution mass spectrometry (HRMS) for the simultaneous identification and quantification of pesticides. Different matrices and extraction methods were addressed: (i) natural grape juice with analysis and optimization of the QuEChERS method for the preparation of the sample (ARTICLE 1); (ii) present a second quantitative application of the use of QuEChERS and LC-HRMS for different matrices (apple, lettuce and wheat flour) (ARTICLE 2); (iii) optimize and use the QuEChERS method with LC-HRMS for quantification of pesticide residues in organic carrots (ARTICLE 3) and (iv) optimize and use the QuPPe method for the extraction of polar pesticides and metabolites, without derivatization, by low resolution mass spectrometry (LRMS) in olive oil (ARTICLE 4). These procedures address the importance of optimizing sample preparation, QuEChERS and QuPPe, to achieve adequate recovery of pesticide residues in food. In addition, it was sought to minimize the matrix effects caused by the interferents present in the extract. In this way, the use of mass spectrometry associated with separation systems (liquid chromatography) has proved to be an adequate analytical tool for identification and quantification of pesticides in complex matrices. This work demonstrates that the control of contamination of different matrices by organic contaminants, demand adequate sample preparation as well as optimization of the analytical system.