Método multirresíduo rápido para a determinação de agrotóxicos em abobrinha empregando QuEChERS modificado e UHPLC-MS/MS

Abstract

In the last decades, the use of pesticides in Brazil and in the world has increased substantially, mainly due to the demand for food. Brazil stands out in the international scenario, mainly in the production and cultivation of fruits, vegetables and grains. Zucchini, a food of high nutritional value, source of carbohydrates, vitamins and antioxidants, is among the main economically most valuable vegetables in the country with high annual productivity. Although it is necessary to employ strategies aimed at increasing the quality and productivity of the food produced, such as the use of pesticides, the incorrect and indiscriminate use of these chemicals can have harmful effects on human health and the environment. Thus, inspection and control agencies establish maximum residue limits (MRL) for different pesticides in food. Therefore, the development of multi-residue methods for the determination of pesticides in foods, including zucchini, is necessary and demonstrates the importance of monitoring and controlling these compounds to ensure food safety for the final consumer. Thus, the objective of this work was to develop a multiresidue method for the determination of pesticides in zucchini using the QuEChERS method and ultra-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). Extraction consisted of 10 g of sample and 10 mL of acetonitrile. The partition step was performed with 1 g of NaCl and 4 g of MgSO4, followed by manual shaking and centrifugation at 3500 rpm for 8 minutes. The extract was diluted 1:4 in ultrapure water, filtered through 0.22 μm syringe filters and analyzed by UHPLC-MS/MS. For the analyses, the Waters Acquity UPLC system with a Xevo TQ mass spectrometer equipped with an electronebulization ionization (ESI) source was used. Chromatographic analysis was performed with an Acquity BEH C18 column (50 x 2.1 mm, 1.7 μm) with mobile phase composed of (A) 2:98 methanol:water (v/v) and (B) 2:98 water:methanol (v/v), both containing 0.1% (v/v) formic acid and ammonium formate at 5 mmol L−1. The flow rate was 0.225 mL min−1 and the total run time was 10 min. Selected reaction monitoring (SRM) was used as the acquisition mode. The original QuEChERS method without cleaning step has been validated for 99 compounds The method was applied to 20 zucchini samples from different cities of Rio Grande do Sul, in which residues of 15 pesticides were found. Based on these results, the proposed method proved to be suitable for multiresidue determination of pesticides in zucchini and can be applied in routine analysis.