Determination of Amide Herbicide Residues in Drinking Water by Gas Chromatography-Tandem Mass Spectrometry

Objective To establish a method for determining propachlor, dimethenamid, acetochlor, alachlor, benthiocarb, metolachlor, butachlor, and pretilachlor in drinking water by solid-phase extraction and gas chromatography-tandem mass spectrometry (GC-MS/MS).

Methods The water samples were extracted by an activated C₁₈ solid-phase column, eluted by acetonitrile-toluene (3∶1, V/V) mixed solution, and then separated by DB-5 MS quartz capillary column, and qualitative and quantitative analyses were performed by GC-MS/MS in multiple reaction monitoring mode.

Results The eight amide herbicides showed a good linear relationship ranged from 1.0 μg/L to 200 μg/L, with a correlation coefficient above 0.999, and the detection limit of this method ranged from 0.14 to 0.32 ng/L. At three spiked concentration levels (0.005, 0.025, and 0.1 μg/L), the recoveries ranged from 75.8% to 106.6%, and the relative standard deviation ranged from 1.3% to 6.2%. This method was applied to the detection of samples, and amide herbicides were detected in water samples.

Conclusion The method is simple, rapid, sensitive, and accurate and can be used for the detection of common amide herbicides in drinking water.