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Simultaneous Extraction of Pesticides and Polycyclic Aromatic Hydrocarbons in Brazilian Cachaça Using a Modified QuEChERS Method Followed by Gas Chromatography Coupled to Tandem Mass Spectrometry Quantification

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journal contribution
posted on 11.12.2018, 00:00 by Mariana C. da Silva, Mauro Lúcio G. Oliveira, Rodinei Augusti, Adriana F. Faria
A modified QuEChERS method was optimized for simultaneous extraction of 93 pesticides and 6 polycyclic aromatic hydrocarbons (PAHs) in cachaça. The procedure employed 20 mL of sample, 10 mL of dichloromethane, 1 g of NaCl, and 6 g of MgSO4. The methods were validated in accordance with pesticide tolerances set by the National Health Surveillance Agency of Brazil and government guidelines of Brazil and the European Union. The linearity of all curves was adequate, with calculated tr higher than the critical value, at the 95% confidence level. For pesticides, recoveries ranged between 86.7 and 118.2%, relative standard deviation (RSD) ≤ 20%, at least at two concentration levels, and limit of detection (LOD) and limit of quantitation (LOQ) were 2.5 and 10.0 μg L–1, respectively. For PAHs, recoveries ranged between 84.8 and 111.5%, RSD was between 6.2 and 27.3%, LOD and LOQ were 0.25 and 1.0 μg L–1, respectively. The combined standard uncertainty was lower than 50% of the relative expanded uncertainty value at concentration levels of greater relevance in both methods. Analyses of five commercial samples detected the presence of 9 pesticides (10.0–128.0 μg L–1) and 6 PAHs (2.0–4.0 μg L–1), indicating the need for a specific legislation for Brazilian cachaça.