Determination of Glufosinate, Glyphosate and Aminomethylphosphonic Acid in Water by High Performance Liquid Chromatography with Ultrasound Assisted Derivatization

The 2 mL of water sample was taken, and 6 mg of trisodium citrate dihydrate, and 1 mL of 0.05 mol·L^-1 sodium tetraborate solution, and 2 mL of 1 g·L^-1 9-fluorene methyl chloroform (FMOC-Cl) solution were added sequentially. The mixed solution was reacted to derivatize targets at room temperature with ultrasonic power of 250 W for 10 min. Then 0.40 g of sodium chloride was added for salting out, and the mixture was vortexed for 2 min, and settled for 1 min. The lower water phase was collected, and passed through a 0.45 μm filter membrane, and the filtrate was analyzed by high performance liquid chromatography. PAH C₁₈ chromatographic column was used as the stationary phase, and the mixed solutions composed of acetonitrile and 0.2% (volume fraction) phosphoric acid solution at different volume ratios were used as the mobile phase for gradient elution separation, and fluorescence detector was used for detection. It was shown that linear relationships between values of the mass concentration of glufosinate, glyphosate, and aminomethylphosphonic acid and the peak area of their derivatization products were kept in the range of 0.400-50.0 μg·L^-1, with detection limits (3.143s) of 0.2, 0.1, 0.1 μg·L^-1, respectively. Test for recovery was made according to the standard addition method, giving recoveries in the range of 87.6%-100%, and RSDs (n=6) of the determined values ranged from 5.7% to 12%. The proposed method was used for the analysis of actual water samples, and the detection results were all negative.