Integrating experimental design with QuEChERS for comprehensive pesticide screening and assessing health risk for okra using GC-MS/MS

A modified QuEChERS method combined with GC-MS/MS was developed for faster and economic analysis of 200 pesticide residues in okra. The QuEChERS method was optimized using two models, Plackett-Burman (P-B) and Central Composite Design (CCD) which improved the accuracy and making the optimization process more efficient and precise. The significant factor included MWCNTs, PSA, magnesium sulfate, and activated charcoal which were used as d-SPE sorbents in a sample clean-up step to remove matrix interference. Calibration curves for the studied pesticides exhibited good linearity (r² > 0.99), with back-calculated concentrations within ≤±20% across the tested range. The method was validated as per SANTE/11312/2021v2 and recoveries at 10 and 25 μg/kg were within 70 to 120% with RSD ≤ 20% for 188 compounds respectively. However, those outside the range were reproducible. LOQ for all targeted pesticide residues was set at 10 μg/kg. The method is rapid, efficient and offer high sensitivity to meet the analytical requirements for pesticide residue analysis and it was applied to analyse 120 okra samples from Ahmedabad and the subsequent health risk assessment shows minimal risk to consumers.