Rapid HPLC-MS/MS Determination of Residual Amounts of 7 Benzoylurea Insecticides in Fruits

Residual amounts of 7 benzoylurea insecticides,i.e.,diflubenzuron,chlorbenzuron,triflumuron,hexaflumuron,flubenzuron,flufenozuron and chlorfluazuron,were determined by HPLC-MS/MS.The mode of multi-reaction monitoring negative ion scanning was adopted for both the quantitative and qualitative analysis.The fruit sample was extracted with petroleum ether,an aliquot of the extract was taken and evaporated to dryness by blowing with nitrogen when heated in a water bath at 45 ℃.The residue was taken up with 1.0 mL of methanol and used for HPLC-MS/MS analysis.The values of lower limit of determination (10S/N) of 2 μg·kg-1 were found for each of diflubenzuron chlorbenzuron,triflumuron,flufenoxuron and chlorfluazuron,and of 0.5 μg·kg-1 for hexaflumuron and flubenzuron.Linear relationships in the range within 100 μg·kg-1 were found for all of the 7 insecticides.Recovery and precision of the method were tested by standard addition method at 3 concentration levels.Results obtained were as follows: recovery 83.8%-94.4%;RSD′s (n=9) of repeatability 3.12%-7.43%,RSD′s (n=9) of reproducibility 3.96%-7.63%.