Rapid determination of glyphosate, glufosinate, bialaphos, and their major metabolites in serum by liquid chromatography-tandem mass spectrometry using hydrophilic interaction chromatography

We developed a simple and rapid method for the simultaneous determination of phosphorus-containing amino acid herbicides (glyphosate, glufosinate, bialaphos) and their major metabolites, aminomethylphosphonic acid (AMPA) and 3-methylphosphinicopropionic acid (MPPA), in human serum. Serum samples were filtrated through an ultrafiltration membrane to remove proteins. The filtrate was then washed with chloroform, and injected into a liquid chromatography-tandem mass spectrometry (LC-MS/MS) system. Chromatographic separation was achieved on a hydrophilic interaction chromatography (HILIC) column. Determination of the target herbicides and metabolites was successfully carried out without derivatization or solid phase extraction (SPE) cartridge clean-up. The recoveries of these compounds, added to human serum at 0.2 mu g/mL, ranged from 94% to 108%, and the relative standard deviations (RSDs) were within 5.9%. The limits of detection (LODs) were 0.01 mu g/mL for MPPA, 0.02 mu g/mL for AMPA, 0.03 mu g/mL for both glyphosate and glufosinate, and 0.07 mu g/mL for bialaphos, respectively. (C) 2011 Elsevier B.V. All rights reserved.