Development of simultaneous analysis for organonitrogen and pyrethroid pesticides with GC/MS

A method was developed for determining 8 organonitrogen pesticides (isoprocarb, propoxur, chlorpropham, bendiocarb, pirimicarb, carbaryl, dichlofluanid and chinomethionat) and 8 pyrethroid pesticides (cyhalothrin, permethrin, cyfluthrin, cypermethrin, flucythrinate, fenvalerate, fluvalinate and deltamethrin) in fruits and vegetables by means of GC/MS. Pesticides were extracted from fruits and vegetables using a mixture of the dichloromethane, cyclohexane, and acetone (1:1:1), then the extracts were applied to a Florisil mini column for clean-up. No serious disturbing peaks were seen in the selected ion monitoring mode in GC/MS analysis, and the quantitation limits were 1 ppb for organonitrogen pesticides and 5 ppb for pyrethroid pesticides. Organonitrogen pesticides were spiked at 10 ppb and pyrethroid pesticides were spiked at 50 ppb in 9 kinds of samples. Except for bendiocarb, recoveries of pesticides were in the range of 63 similar to 77%. The proposed method is satisfactory for the screening of residual pesticides in vegetables and fruits.