Dados do Trabalho

Título

DETERMINATION OF PESTICIDES RESIDUES IN OLIVE OIL USING LIQUID CHROMATOGRAPHY COUPLED TO LOW AND HIGH RESOLUTION MASS SPECTROMETRY

Introdução

Over the past few decades, olive oil has emerged as a super functional food, prized for its proven health benefits. In recent years, the cultivation of olive trees has increased in Brazil, especially in the state of Rio Grande do Sul. However, there is still no established pesticide residue legislation for olive cultivation, and maximum residue limits have been established for only 31 pesticides. As a result, unauthorized substances may be used for pest control. Therefore, the development of an analytical method that allows the determination of pesticides of different classes in olive oil is essential to ensure that the product is safe for the consumer. Sample treatment is undoubtedly the most important step in the analysis of olive oil, since small amounts of lipid residues present in the final extracts can damage analytical columns, detectors or cause signal suppression.

Material e Métodos

The aim of this study was to develop and validate a simple analytical strategy based on the QuEChERS method and UHPLC-MS/MS. To extend the range of compounds, samples were analyzed in a non-targeted mode using a UHPLC-Q-Orbitrap. The extraction method was based on 1 g of olive oil, water, acetonitrile and NaCl, followed by manual stirring for 1 min and centrifugation at 5000 rpm for 5 min until the partition step. The upper layer phase was frozen at -18 ºC for 1 hour. After another centrifugation step, an aliquot was transferred to a 15 mL polypropylene tube containing MgSO4, C18 and PSA. The tube was centrifuged and the extract filtered prior to analysis. The method has been validated for 80 compounds.

Resultados e Discussão

Most of the pesticides analyzed showed recoveries between 70 and 120% with RSD <20%. The limit of quantification ranged from 8 to 170 µg kg-1. The proposed method was applied to more than 20 samples of olive oil produced in Brazil. Among these samples, 6 showed the presence of at least one of the evaluated pesticides, such as difenoconazole, tebuconazole, trifloxystrobin, in the concentration range between 0.164 and 0.949 mg kg-1.

Conclusão

The results show that the proposed method is suitable for the determination of pesticides in olive oil.