QuEChERS Extraction of Pesticide Residues in Caja-Mango using Gas Chromatography with Flame Ionization Detection

Abstract

Contamination of food by pesticide residues is one of major society's concerns in nowadays regarding the food safety. Simplified methodologies to determine the presence and quantity of these contaminants in food are increasingly needed. In this context, the objective of this work was to develop a modern methodology for extraction of pesticide residues in caja-mango pulp, fruit frequently consumed and in large quantity in the Brazilian Cerrado. The proposed method was the QuEChERS for extraction of pesticide residues from the caja-mango pulp and quantification by gas chromatography with flame ionization detection (GC-FID). Initially, the variant of QuEChERS method was evaluated that best resulted in the extraction of carboxin, chlorpyrifos, diphenoconazole and thiabendazole residues from the caja-mango. The best result was obtained for the original method, which uses NaCl and MgSO4 for extraction. Then, because it is an optimized methodology, the QuEChERS-GC-FID method was validated according to the European Community Validation Guide, Guia Sante, as it is the most appropriate and rigorous criterion for acceptance of methodologies for determining pesticide residues. The QuEChERS-GC-FID method presented good linearity (r > 0.992), good precision (in terms of repeatability and reproducibility in the laboratory, with relative standard deviation less than 20%) and good accuracy, with mostly recoveries in 80-120% range. The method was selective, with no pronounced matrix effect in the determinations, but showed worse detectability levels than other methods intended for the same purpose, where the limit of quantification was in the range of 0.36-0.72 mg/kg. Despite the lower detectability and limit of quantification, these values were below the residual maximum limits for the pesticides studied, giving the QuEChERS-GC-FID method suitable applicability for the extraction of pesticide residues from caja-mango pulp.