AMPA-15N – Synthesis and application as standard compound in traceable degradation studies of glyphosate

Stable isotope labeling of pollutants is a valuable tool to investigate their environmental transport and degradation. For the globally most frequently used herbicide glyphosate, such studies have, so far, been hampered by absence an analytical standard for its labeled metabolite AMPA-15N, which formed during degradation all commercially available glyphosate isotopologues. Without standard, detection quantitation e.g. with LC-MS/MS, not possible. Therefore, synthetic pathway AMPA-15N from benzamide-15N via hemiaminal was developed. obtained in sufficient yield purity be as compound LC-MS/MS analysis. Suitable MS-detection settings well calibration using internal (IS) approach were established Fmoc-derivatized AMPA-15N. The use different AMPA isotopologues IS complicated parallel formation [M+H]+ [M]+• AMPA-Fmoc precursor ions ESI-positive mode, causing signal interferences between analyte IS. We recommend either AMPA-13C–15N, AMPA-13C–15N-D2 or isotopologue IS, they do affect linearity curve. As proof concept, developed analysis procedure refine results field lysimeter experiment investigating leaching glyphosate-2-13C–15N. newly enabled soil extracts showed that similar amounts (0.05 – 0.22 mg·kg–1) parent primary persisted topsoil over study period one year, while vertical through column did occur compounds. herein concepts will facilitate future design execution experiments on fate glyphosate.