Evaluation of method performance and matrix effect for 57 commonly used herbicides in some vegetable families using LC-MS/MS determination

Abstract

A modified QuEChERS method was employed with LC-MS/MS to evaluate the matrix effects of 12 different vegetables matrices in 57 globally used herbicides. The average recoveries of pesticides at different concentrations varied between 70 and 120%. The reproducibility expressed as relative standard deviation was <25%. The limit of quantitation was (0.005–0.01 mg/kg). The measurement uncertainty is lower than 40%. Three vegetables families: Cucurbitaceae, Solanaceae and leafy vegetables were selectd for study. Among the investigated commodities, leafy green vegetables have the highest matrix effects, MEs percentages ranged between (2 & 282%). The highest suppression in analytes response was observed for parsley with matrix ME (2–19%). Most of tested herbicides showed suppression extent at the lower fortified concentrations. Tomato recorded the highest enhancement in most of studied herbicides of MEs% ranged from (122 to 379%). Butachlor, chlorbromuron, fenoxaprop-p-ethyl, flufenacet, fluzafop-p-butyl, hexythiazox, prosulfocarb and pyriproxyfen showed ion suppresion for all vegetables matrices with MEs% ranged from (5 to 79%). Matrix effects (MEs) were evaluated by comparing the slopes of target analytes to prove reproducibility (n = 5). The current study emphasize using of matrix match calibration with these commodity pesticides combinations, whereas, ME’s were dependent on composition of analyte and co-eluting agents.

Keywords

• weedkillers
• agriculture products
• quechers
• multiresidue methods
• tandem mass spectroscopy
• signal suppression