UHPLC-MS/MS Determination of Residual Amounts of 34 Organophosphrous Pesticides in Rice

A method of UHPLC-MS/MS for the determination of residual amounts of 34 organophosphrous pesticides in rice was proposed. Sample was extracted with acetonitrile, and the extract was separated with n-hexane (saturated with acetonitrile) and NaCl solution by liquid-liquid partition. The supernatant was concentrated and purified by NH2-solid phase extraction column. The ACQUITY UPLC BEH C18 column was used as chromatographic column, and positive electrospray ionization as well as multiple reactions monitoring mode were used in the detection. Values of lower limit of determination (S/N≥10) of 34 organophosphrous pesticides found were less than 0.01 mg·kg-1. Tests for recovery and precision were made by addition of standard solution at 3 different concentration levels to rice samples which were then analyzed by the proposed method. Values of recovery found were in the range of 60.3%-112%, and values of RSD′s (n=6) less than 18%.