Determination of Pesticides Residues in Food of Plant Origin

The use of pesticides began in the mid-30’s with the development of new chemical compounds to increase agricultural production, with the purpose to meet the world’s population food needs. However, its poor degradation and propagation made them a major problem for public health and the environment. These are responsible for soil and water pollution and cause adverse effects on human health. They present a high risk especially for children, since the enzyme activity and its metabolic systems are not fully active. Taking into account these effects and since it is inevitable the presence of pesticides residues in food, were set maximum residue limits (MRLs), below which the risk to consumers health is not significant. The chromatographic methods are the most used in the analysis of pesticide residues, and gas chromatography (GC) the most widely analytical method applied in foods of plant origin. This study aimed to validate the method of gas chromatography with electron capture detector (GC-ECD) for the determination of pesticide residues in foods of plant origin, The methodology involved the study of selectivity, linearity, precision, detection (LOD) and quantification (LOQ) limits, and accuracy of the method, accordingISO/IEC 17025(1). The purpose of this study was to develop an analytical method for determining residues pesticides from organochlorine chemical group (α-BHC, Aldrin, β-BHC, δ-BHC, Dieldrin, Heptachlor, Heptachlor isomer A, Heptacloro isomer B, Lindane and Nitrofen) and organophosphate chemical group (Dasanit, Disulfoton, Terbufos), for routine analysis. Pulp fresh apple were utilized as samples in this study. Silica-Based SPE Cartridges and C18 SPE cartridges were used in sample extraction step and both showed good performance. The analyses were performed in Hewlett Packard 6890 GC with G2397A μECD detector. The separation was performed on a HP-5 capillary column with temperature programming rates. The calibration curves showed correlation coefficients with a minimum value of 0.989 and a good linear fit to the concentration ranges set for each pesticide, ensuring the linearity of the method. The variation coefficients obtained for all compounds, are comprised between 4.32% and 12.7%, well below 20%, giving a high precision of the method. The values of the limits of detection and quantification were appropriate for the determination of pesticides analyzed, the highest LOQ was 0.009 μg/mL, lower than the maximum residue standard (MRLs) of 0.01 μg/mL established by legislation (2). In conclusion, the extraction method used in the present study was inexpensive (do not require skilled operators, high volume of solvent or costly apparatus), easy and rapid. Additionally, the validation parameters show that the proposed method in this study is sensitive and could efficiently be used in the routine analysis