Dissipation kinetics, dietary risk assessment and decontamination studies of tolfenpyrad in okra

QuEChERS method with liquid chromatography-mass spectrometry (LC-MS/MS) technique was employed for the estimation of tolfenpyrad residues in okra crop. The method was validated in terms of linearity, matrix effect, limit of quantification (LOQ), limit of detection, recovery, repeatability and reproducibility as per SANTE guidelines. After two applications of tolfenpyrad @150 (X), 187.5 (1.25X), 300g a.i. ha-1 (2X), the mean initial residues were found to be 0.57, 0.78, and 1.21mgkg -1. The residues reached below limit of quantification of 0.01mgkg-1 after 10th, 15th, and 20th day at all the three doses, respectively. Dissipation kinetics of tolfenpyrad in okra was calculated to follow first order kinetics with half-life (T1/2) values of 2.10, 2.16, and 2.24 days at X, 1.25X and 2X dosages, respectively. Risk assessment in terms of hazard quotient (HQ) revealed that the application of tolfenpyrad was safe for safe consumption. Decontamination processes involved tap water wash, soaking in 2% salt solution, soaking in 2% salt solution along with boiling, soaking in 0.1% sodium bicarbonate solution, soaking in 0.01% potassium permanganate solution, boiling and frying. Frying followed by soaking in 2 per cent salt solution along with boiling proved to be highly effective in reducing tolfenpyrad residues by 80-85 and 76-79 per cent, respectively at all the three treatments.