Vol. 9, Issue 5, Part C (2025)

This study involves development of multiresidue low cost, effective and quick, modified QUECHERS (Quick Easy Cheap Effective Rugged and Safe) extraction method and extract clean-up with MgSO₄, PSA & SPE including direct sample injection without clean-up at different spike levels in combination with high performance liquid chromatography coupled to tandem mass spectrometric with electrospray ionization (UPLC-MSMS-ESI) was performed. To study recovery efficiencies samples were spiked at 5, 10, 20 and 50 µg/kg in rice bran and paddy. Recoveries in rice bran from mixed clean-up of MgSO₄, PSA and C18 were ranged between 70-120% except at 5µg/kg where recovery of chlorpyrifos, formothion and phosalone were less than 70% and all the RSD calculated were found to be less than 20% for spike level of 5, 10, 20 and 50 µg/kg. Recoveries from individual clean-up reagents i.e., MgSO₄ and PSA were also within range of 70-120% (N=6) and RSD of less than 20% but recovery by solid phase extraction (SPE) were found to be ranged between i.e., 47-89% (N=6) at 20 µg/kg but were improved at higher spike level of 50µg/kg. Calibration curve linearity has coefficient of determination (R²) of 0.995 or higher starting from 5.0 to 200 µg/kg. Developed method successfully demonstrate the capability to quickly and efficiently determine multiresidue organophosphate pesticides in both rice bran and paddy crop by single LC-TQ-MS.