31 May '16, 1pm
Glyphosate has been found in the urine of 93% of Americans tested
Glyphosate (N-(phosphonomethyl)glycine ) is directly analyzed using liquid chromatography- tandem mass spectrometry (LC-MS/MS). Water and urine samples are prepared for analysis by solid phase extraction using an ion exchange column. Extracted samples are injected to the LC-MS/MS and the analyte is separated using an Obelisc N column (SIELC Technologies, Prospect Heights, IL) through isocratic elution. Ionization of glyphosate is achieved using an electrospray ionization source operated in negative polarity. The analyte is detected by multiple reaction monitoring using a 13C-labelled glyphosate as internal standard. Quantification of the analyte is done by isotope dilution method using an eight-point calibration curve.