Pesticides residue analysis and associated human health risk assessment in tomato and onion

Pesticides are extensively used in modern agriculture to safeguard crops against pests and diseases. Nevertheless, their residual presence in food products may pose potential risks to both human health and the environment In this research, a sample preparation method based on QuEChERS, combined with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), and gas chromatography-mass spectrometry (GC-MS) was employed to detect 70 targeted pesticide residues in onion and tomato samples. The method was validated using both UHPLC-MS/MS and GC-MS analytical systems. An overall linear range of 0.004-0.5 for UHPLC-MS/MS and 0.006-0.5 mg kg^-1 for GC-MS was achieved, with determination coefficients (R²) exceeding 0.99 in both cases. The limits of detection (LOD) ranged from 0.001-0.027 for UHPLC-MS/MS and 0.002-0.030 mg kg^-1 for GC-MS, while the limits of quantification (LOQ) were 0.004-0.050 mg kg^-1 and 0.006-0.050 mg kg^-1, respectively. Method accuracy and precision were evaluated at two concentration levels (0.05 and 0.1 mg kg^-1) with 5 replicates (n = 5) yielding recoveries between 71.1 and 121.6%, and relative standard deviations (RSD) bellow 22.8% (Wondimu & Geletu, 2023). The validated method was applied to 200 collected samples (100 onion and 100 tomato), revealing a higher frequency of pesticide residues in tomato samples compared to onions. To assess consumer safety, a risk assessment was conducted based on the obtained results. Additionally, the environmental sustainability of the analytical method was evaluated using the AGREE and GAPI tools.