SIMULTANEOUS DETERMINATION OF VARIOUS PES TICIDES IN RICE BY ION-TRAPGAS-CHROMATOGRAPHY MASS-SPECTROMETRIC (CHEMICAL-IONIZATION METHOD) ANALYSIS

Various pesticides in polished and unpolished rice were simultaneously extracted and determined by ion-trap GC/MS with chemical ionization u sing isobutane. Among 62 pesticides (25 organonitrogen pesticides, 25 organophosphorus pesticides, 7 organochlorine pesticides and 5 pyrethr oid pesticides), almost all, except BHC, endrin and endosulfan, gave s everal fragment ions in GC/MS (CI method) and the sensitivities were t en times higher than in the EI mode. Recoveries of the pesticides spik ed at 0.1 ppm in rice were more than 50% except for several pesticides , and the detection limit for each was 0.005 ppm by the proposed metho d.