Occurrence and Health Risk of Multiclass Pesticide Residues in Tomatoes From Bangladesh via Modified QuEChERS-LC-MS/MS.

Abstract

An adapted QuEChERS extraction protocol coupled with LC-MS/MS analysis was established to enable concurrent quantification of 11 different pesticides in tomato specimens obtained from Dhaka, Bangladesh. Acetonitrile (ACN) was used for pesticide extraction, and among different sorbent combinations tested, the 50 mg primary secondary amine, 10 mg C18, and 3 mg graphitized carbon black with minimal matrix effects was selected for d-SPE cleanup. The pesticides exhibited good linearity over a wide linear range of 0.1-200 μg/L, with R2 ≥ 0.9925 in solvent and matrix-matched calibration. The method exhibited high sensitivity with limit of detection = 0.10 to 1.10 μg/kg and limit of quantitation = 0.33 to 3.33 μg/kg. The newly developed method showed excellent results in recovery studies (80.0%-91.6%) at five (n = 5) different fortification levels (10, 20, 50, 100, and 200 μg/kg) with relative standard deviations ≤9.0%. Azoxystrobin and difenoconazole were the most frequently detected pesticides, with residue levels ranging from 0.41 to 97.33 μg/kg and 1.58 to 177.2 μg/kg, respectively. The hazard quotient and acute health index values remained below 1 for all pesticides, indicating no significant health risk. This study confirms that tomato samples from Dhaka were largely compliant with MRLs, supporting safer local production but indicating the need for regular monitoring.