DETERMINATION OF ATRAZINE AND HYDROXYATRAZINE IN AGRICULTURAL RUNOFF WATERS BY LIQUID-CHROMATOGRAPHY AND FAST ATOM BOMBARDMENT-HIGH RESOLUTION MASS-SPECTROMETRY

Agricultural surface water samples were collected after the first 2 ma jor runoff events in 1994 for determination of atrazine (ATR, 2-chloro -4-ethylamino-6-isopropylamino-s-triazine) and hydroxyatrazine (HA, et hylamino-4-hydroxy-6-isopropylamino-s-triazine), After addition of C-1 3(3)-labeled ATR and C-13(3)-labeled HA as internal standards, the che micals were quantitatively extracted and eluted from water samples by liquid-solid extraction with a carbon black cartridge. Liquid chromato graphy and fast atom bombardment-high resolution mass spectrometry wer e used to analyze the sample extracts, Concentrations of ATR ranged fr om 8.2 to 15.1 parts per billion (ppb) in the samples collected after both runoff events from a highly agricultural watershed in south-centr al Nebraska, HA concentrations ranged from 0.25 to 2.7 ppb in the wate r samples. Results obtained from both analytical procedures agreed wit hin a 15% deviation, As predicted from runoff events, the highest leve ls occurred in samples from the first collection on June 24, 1994, for both ATR and HA, whereas samples collected on July 5, 1994, contained much lower levels of HA.