Determination of triazine herbicides in foods with liquid chromatography mass spectrometry

Eight residual triazine herbicides and three metribuzin metabolites in foods were determined by liquid chromatography mass spectrometry (LC-MS) with an atmospheric pressure chemical ionization (APCI) interface, under both positive and negative ion modes. Herbicides were extracted with acetonitrile, and no cleanup procedure was adopted in this method. Four foods were spiked with eight herbicides and three metabolites at 0.05 ppm. The average recoveries of these herbicides usually ranged from 82 to 99% and the relative standard deviations were usually around 10%. These results suggest that LC-MS with APCI can be used to determine residues of triazine herbicides in foods.