U.S. Geological Survey
Open-File Report 01-454

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Methods of Analysis by the U.S. Geological Survey Organic Geochemistry Research Group--Determination of Glyphosate, Aminomethylphosphonic Acid, and Glufosinate in Water Using Online Solid-Phase Extraction and High-Performance Liquid Chromatography/Mass Spectrometry

Abstract

An analytical method for the determination of glyphosate, its principal degradation compound, aminomethylphosphonic acid (AMPA), and glufosinate in water with varying matrices has been developed. Four different sample matrices fortified at 0.2 and 2.0 Îg/L (micrograms per liter) were analyzed using precolumn derivatization with 9-fluorenylmethylchloroformate (FMOC). After derivatization, cleanup and concentration were accomplished using automated online solid-phase extraction followed by elution with the mobile phase allowing for direct injection into a liquid chromatograph/mass spectrometer (LC/MS). Analytical conditions for MS detection were optimized, and quantitation was carried out using the following representative ions: 390 and 168 for glyphosate; 332, 110, and 136 for AMPA; and 402, 180, and 206 for glufosinate. Matrix effects were minimized by utilizing standard addition for quantification and an isotope-labeled glyphosate (2-¹³C,¹⁵N) as the internal standard. Method detection limits (MDLs) were 0.084 Îg/L for glyphosate, 0.078 Îg/L for AMPA, and 0.057 Îg/L for glufosinate. The method reporting limits (MRLs) were set at 0.1 Îg/L for all three compounds. The mean recovery values ranged from 88.0 to 128.7 percent, and relative standard deviation values ranged from 5.6 to 32.6 percent.

Additional information about the Organic Geochemistry Research Laboratory can be found at: http://ks.water.usgs.gov/studies/reslab/

Lee, E.A., Strahan, A.P., and Thurman, E.M., 2002, Methods of Analysis by the U.S. Geological Survey Organic Geochemistry Research Group--Determination of Glyphosate, Aminomethylphosphonic Acid, and Glufosinate in Water Using Online Solid-Phase Extraction and High-Performance Liquid Chromatography/Mass Spectrometry: U.S. Geological Survey Open-File Report 01-454, 13 p.