Determinação de resíduos de agrotóxicos em azeite de oliva e azeitonas empregando método QuEChERS e UHPLC-MS/MS

Abstract

Commonly used in the Mediterranean diet, olive oils and table olives have become more frequent in the everyday meals of the Brazilian consumer. Despite the small consumption per capita, the country is already the second biggest importer of the fruit. The main provider is Argentina, followed by Spain, Portugal and Chile. In the last years, Brazil has been increasing olive growing, mainly in the Rio Grande do Sul state. However, there is not stablished law for olive trees cultivation and only one insecticide is permitted for olives. Therefore, many producers have to apply restricted pesticides, in the need to fight pests, like the olive fly, olive tree moth, rust and others. Therefore, the need to develop an analytical method to determine pesticide residues from different classes in olive oils and table olives, to guarantee that the produce brought to the consumer are not contaminated. This research developed and validated an analytical method for the determination of 80 different pesticides in olive oil and table olives employing QuEChERS and ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). The extracts were analysed by UHPLC-MS/MS according to the validation criteria stablished by SANTE. The proposed method showed adequate for the determination of 80 pesticides in olive oil and table olives. LOQ ranged from 0.5 to 10 μg L-1 and the LOD from 0.15 to 3 μg L-1 with adequate accuracy (70 to 120%) and precision (RSD ≤20%). The proposed method was applied in 23 samples of olive oils and 11 table olives from national and imported brands. From those, six samples of olive oils and all samples of table olives showed at least one pesticide above the LOQ. The compounds allowed by the Brazilian law were not detected in the samples. However, the fungicide difenoconazole, allowed for olive growing by Codex Alimentarius, showed concentration below the maximum residues limit.