Heating, Identification and Determination of Pesticides Residues in Black Bean Samples

Abstract

The advantages associated with pesticide application in increasing agricultural productivity must be weighed against the possible danger to health and the environment. Above all, the application of these agents must be in accordance with good agricultural practice. The presence of pesticide residues above acceptable daily intake values and maximum residue limits is of concern from a food safety point of view. The removal of food residues by processing may be affected by the nature of the food, type of active ingredient and specificity of the processing applied. Chronic organophosphate contamination can affect the renal, reproductive, respiratory and nervous systems. The present work aimed to identify and determine the residues of ten organophosphates (chlorpyrifos, etione, malathion, methamidophos, parathion-methyl, phenthoate, phorate, pirimiphos-methyl, terbuphos, pyrazophos, and triazophos) added to common bean samples (Phaseolus vulgaris) and to observe the effect of heat treatment on these analytes. The QuEChERS method (Quick, Easy, Cheap, Effective, Robust and Safe) was used for the extraction of multiple waste before and after heating. Gas chromatography coupled to the thermionic flame detector (FTD) was used to identify and determine the analytes. Moreover, in this study, the methodology was also validated by determining the ten organophosphates previously mentioned, and metamidophos by studies of selectivity, linearity, intermediate precision, detection limit, quantification limit and precision study by addition and recovery. According to the results obtained in the work, it was possible to notice that, under the conditions in which the experiments were conducted, the organophosphates were thermosensitive. The temperature and cooking time used were lower than traditional beans dishes. The method was selective for all analytes, as there was no interference greater than 30% of the quantification limit. The limits of detection were between 1.60 and 52.96 ng.kg-1 and the limits of quantification were between 3.30 and 176.0 ng.kg-1. Regarding intermediate precision, the differences in area values were = 15 % at different concentrations except for phorate. The correlation coefficients (r) of the linearity curves were greater than 0.99 for all active ingredients within the applied working range. The recovery percentage was between 70 and 120 %, except phorate. Thus, the methodology was satisfactory for the identification and determination of nine of the eleven organophosphates analyzed in beans.