Determination of 42 Kinds of Pesticide Residues with Gas Chromatography Mass Spectrometry and Selected Ion Monitoring

[Objective]To establish the method of gas chromatography mass spectrometry(GC-MS) and selected ion monitoring(SIM) for the determination of organophosphorus,pyrethroid,organochlorine,carbamate and weedicide pesticide residues in foods.[Methods] The pesticides were extracted with acetone and dichloromethane,warmed with water at 40℃,and circumrotated and evaporated until it was nearly dry,then it was purified by Envi Carb column and Sep Pak NH2 column.Afterwards,gas chromatography mass spectrometry(GC-MS) and selected ion monitoring(SIM) were used to determine 42 pesticide residues,such as organophosphorus,pyrethroid,organochlorine,carbamate and weedicide.[Results] All the 42 kinds of pesticide residues were drained out within 36 minutes,the separation was fine;the standard linear range was between 0.005~1.0μg/ml;correlation coefficient r was above 0.99;the labeled recovery rates were between 90% and 96%;the relative standard deviations(RSD) was below 10%;the limit of determination(LOD) was 0.005mg/kg(S/N=3).[Conclusion]This method is suitable for determining pesticide residues in foods with satisfactory sensitivity,accuracy and precision;it can rapidly detect 42 kinds of pesticide and the concentration level reaches the requirement for detection.