A comparative analysis of pesticides residues in tobacco leaves cultivated in Iran and different parts of the world

Pesticides are widely used worldwide for agricultural purposes. Exposure to pesticide residues in tobacco products can have negative effects on human health. In the present study, samples of tobacco leaves were collected from five regions of Iran and five countries (imported products) to assess the presence of pesticide residues from the tobacco complex located in Gilan, Iran. The residuals of 57 pesticides were analysed using LC-MS/MS and GC-ECD techniques, employing the QuEChER sample preparation method, which involved acetonitrile extraction followed by dispersed solid phase extraction (d-SPE) utilising primary secondary amine (PSA) and graphitised carbon black (GCB) adsorbents. Validation of the analytical methods was performed based on parameters such as percentage relative standard deviation (RSD), Limits of Detection (LOD), and Limit of Quantification (LOQ). In most of the samples, the pesticides residuals were lower than the Guidance Residue Levels (GRLs) of the Cooperation Centre for Scientific Research Relative to Tobacco (CORESTA). Concerning organophosphorus compounds and carbamates, the Iranian samples exhibited the highest average concentration of the Thiodicarb pesticide (525.2 µg/kg). In imported samples, the highest average residual concentration was observed for the dichlorine pesticide (206.3 μg/kg) across all samples. Among all samples for organochlorine compounds, pesticides p, p'-DDT (381.9 µg/kg), and Cyromazine (94.7 µg/kg) displayed the highest average residue in Iranian and imported samples, respectively. It should be emphasised that despite the prohibition of certain pesticides in agricultural lands, of the remain of these organic compounds can still be detected in tobacco leaves in different parts of the world.