Agilent Technologies announces highly sensitive method for analyzing herbicide amitrol in water

01-07-2004: Agilent Technologies Inc. announced a highly sensitive method available for characterizing amitrol in water at detection levels well below the European Commission advisory level of 0.1 ug/L.

Amitrol is used both as an herbicide and photographic chemical. A suspected carcinogen, it has been cited as a hazardous substance by the EPA and National Institute for Occupational Safety and Health.

Sub-parts-per-billion analysis of amitrol in water raises two challenges: Amitrol's low molecular weight does not produce a specific, recognizable ion in mass spectrometry, and this highly soluble compound is difficult to recover in a water sample. Both challenges can be solved by in situ derivatization with hexylchloroformate.

Agilent chemists used this derivatization technique, solid phase extraction and liquid chromatography/mass selective detection to analyze amitrol with minimum sample preparation. The scientists performed the analysis on an Agilent 1100 Series LC/MSD system operated in atmospheric pressure chemical ionization mode with selective ion monitoring and large volume injection (100 uL). This method characterized amitrol at the ppb level (0.02 ug/L).

The repeatability of the analysis was verified by quantifying six standard solutions (50 mL each) at 0.05 ppb amitrol and 0.5 ppb internal standard. The complete derivatization and extraction procedure gave a relative standard deviation of just 6.5 percent.