Determination of chlorophenoxy herbicides in waters by capillary gas chromatography with ion trap detection

A method for the determination of 4-chloro-2-methylphenoxyacetic acid (MCPA), 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) in water samples is reported. Methyl esterification with boron trifluoride-methanol (BF3-CH3OH) and mass spectrometric detection in the electron ionization mode (EI-MS) have been evaluated. The use of mass spectrometry detection places less pressure on the need for a very efficient clean-up procedure. Further, herbicides positively identified in samples are automatically confirmed without resorting to a mass spectrometer. In this procedure we can avoid the clean-up procedure and the use of anhydrous sodium sulfate as a drying agent. The water samples were acidified to pH