Analytical control of pesticide residues in food safety assessment

Introduction. The reliability of the analytical control results is directly related to the methods of sample preparation and measurement used. Suppression/amplification of the signal of the test substance in the presence of matrix components is one of the main problems in the analysis of complex samples. The aim of the study was to evaluate the applicability of different calibration approaches in the determination of organochlorine pesticide residues in food products intended for baby food. Material and methods. The objects of the study were samples of baby food products belonging to various product groups. The subject of analytical control was organochlorine substances included in the list of pesticides prohibited for use in the production of baby food products. The measurements were performed using the tandem gas chromatography-mass spectrometry (GC-MS/MS) method, sample preparation was performed using the QuEChERS method. Results. Comparison of data obtained by calibration using an external standard on a solvent and by calibration using an external standard matched to the matrix shows that both calibration options demonstrate a high correlation coefficient, however, the signal intensity on the chromatograms with matrix calibration is significantly higher for dieldrin, hexachlorobenzene, heptachlor, and its metabolite heptachlor epoxide. With respect to aldrin, a significant (more than 20%) signal increase is observed only in fruit and vegetable products. Limitations. The study was conducted on individual samples of food products for baby food, belonging to a number of product groups. Conclusion. Signal amplification/suppression is directly related to the structure and physical and chemical properties of the substance and the nature of the analyzed matrix. Using solvent calibration can overestimate the results by dozens of times and lead to unjustified conclusions about the non-compliance of the studied product with safety requirements.