Liquid chromatography-tandem mass spectrometry (LC-MS/MS) based prevalence and dissipation analysis of acetamiprid and bifenthrin in okra after foliar application

The acetamiprid, and bifenthrin residues levels in the okra crop were assayed using a QuEChERS extraction method combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS). The technique was subsequently checked for linearity, matrix effect, recovery, repeatability, reproducibility, and limit of quantification (LOQ). A salting-out mixture comprising magnesium sulphate, sodium chloride, disodium hydrogen citrate sesquihydrate and trisodium citrate dihydrate offered quick and rapid extraction of acetamiprid and bifenthrin residues from okra. The devised method was found to be linear for the recovery of acetamiprid and bifenthrin with regression coefficients (R2) of 0.9577 and 0.9698, respectively. After applying a ready-made mixed formulation of acetamiprid (25 g a.i. ha-1) and bifenthrin (12.5 g a.i. ha-1), the average initial deposits on okra vegetables were 0.175 mg/kg and 0.062 mg/kg, respectively. The residues of acetamiprid and bifenthrin fell below the LOQ of 0.01 mg/kg after 14 and 4 days of foliar spray, respectively. The dissipation kinetics of acetamiprid and bifenthrin followed first-order kinetics with half-life values (t1/2) of 3.74 and 2.18 days, respectively. The comparison between observed levels of acetamiprid and bifenthrin and European Union Maximum Residual Limits reveals it is safe to harvest okra one day after applying the recommended dose. Overall, the salting out conditions followed by liquid chromatography coupled with tandem mass spectrometry may provide a rapid and pragmatic solution for analysts and stakeholders to ensure the adherence to the safety and responsible use of these pesticides in agriculture