Detection of Glyphosate and 2,4-D in Water by Normal-phase Chromatography Electrospray Ionization Tandem Mass Spectrometry

Objectives To setup a method for detecting glyphosate and 2,4-D in drinking water by liquid chromatography-tandem mass spectrometry (LC-MS-MS).

Methods Using Chromatographic column: CAPCELL PAK ST(2.1 mm × 150 mm) and mobile phase: acetonitrile/10 mmol/L ammonium acetate solution (pH=10.10) for the separation of samples; after passing a 0.22 μm filter membrane, samples were detected by LC-MS-MS.

Results At spiked levels for glyphosate (100.0 ng/mL, 400.0 ng/mL) in water, the detected concentrations were 95.3±3.8 ng/mL and 402.7± 20.8 ng/mL, the average recoveries were 95.3% and 100.7%, and the linear regression coefficient for glyphosate at the concentration of 20.0~800.0 ng/mL was 0.9992. At spiked levels for 2,4-D (10.0 ng/mL, 40.0 ng/mL) in water, the detected concentrations were 9.7± 0.2 ng/mL and 38.6±1.0 ng/mL, the average recoveries were 97.0% and 96.5%, and the linear regression coefficient for 2,4-D at the concentration of 2.0~80.0 ng/mL was 0.9996. The limit of detection (S/N=10) for glyphosate was 4.0 ng/mL and for 2,4-D was 0.4 ng/mL.

Conclusions The method was simple and fast, had a good accuracy and high sensitivity, which could meet the needs for the determination of paraquat glyphosate and 2,4-D in drinking water.