Abstract: A liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) method was developed for the determination of imidacloprid in vegetable and tea samples. The sample was first extracted with acetonitrile and then cleaned up with Florisil and active charcoal column. The precursor ion/product ion transitions m/z 256.0/209.3 and m/z 256.0/175.2 were monitored, and m/z 209.3 was used for quantification. The good linearity was obtained in the range of 0.01-0.5 mg/L with the correlation coefficients (r2) more than 0.997. The limit of quantification was 0.01 mg/kg. The recoveries were 76%-90% at the spiked levels of 0.01,0.05 and 0.2 mg/kg with the relative standard deviations of 7.4%-11.0%. The method is rapid, sensitive and specific for imidacloprid analysis.

Key words: imidacloprid, residues, tea , vegetable, liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS)