Rapid determination of organophosphorus pesticides in edible vegetable oils by direct microextraction using magnetic mesoporous silica microspheres

Abstract

AbstractThis study describes a rapid and sensitive method for the detection of four organophosphorus pesticides in edible vegetable oils by magnetic mesoporous silica microsphere (mSiO2@Fe3O4) extraction. Organophosphorus pesticides were directly extracted from oil sample using mSiO2@Fe3O4 after diluting with n‐hexane. Compared with traditional sample preparation methods, this procedure is less time consuming and it does not necessitate environmentally unfriendly solvent extraction / centrifugation processes. Moreover, the matrix effect can also be suppressed by size‐exclusion interaction due to mesoporous structure of mSiO2@Fe3O4 and large molecules of fat. Clean analytes were analyzed by liquid chromatography with tandem mass spectrometry. Variables affecting extraction of organophosphorus pesticides were optimized. Under the optimized conditions, the whole pretreatment process could be accomplished within 10 min. Acceptable linearity in the range of 5–1000 ng/g was obtained for four organophosphorus pesticides with satisfactory R2 of 0.9858∼0.9983. The limits of detection ranged from 0.2 to 0.6 ng/g. The method recoveries at three spiked concentration levels (10, 100 and 1000 ng/g) were from 92.1 to 108.6% with interday and intraday relative standard deviations less than 5.9 and 13.4%, respectively. Finally, the established method was successfully applied for the determination of organophosphorus pesticides in real edible vegetable oils.