| Autor: |
Rusli O; School of Chemistry, UNSW Sydney, Sydney, NSW, 2052, Australia. n.rijs@unsw.edu.au., Lloyd Williams OH; School of Chemistry, UNSW Sydney, Sydney, NSW, 2052, Australia. n.rijs@unsw.edu.au., Chakraborty P; Institute of Nanotechnology, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany., Neumaier M; Institute of Nanotechnology, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany., Hennrich F; Institute of Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany., Bakels S; Division of Bioanalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands.; Centre for Analytical Sciences Amsterdam, 1098 XH Amsterdam, The Netherlands., Hes K; Division of Bioanalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands.; Centre for Analytical Sciences Amsterdam, 1098 XH Amsterdam, The Netherlands., Rijs AM; Division of Bioanalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands.; Centre for Analytical Sciences Amsterdam, 1098 XH Amsterdam, The Netherlands., Ucur B; Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, NSW, 2522, Australia., Ellis SR; Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, NSW, 2522, Australia., Pachulicz RJ; Department of Chemistry, School of Physics, Chemistry and Earth Sciences, The University of Adelaide, Australia., Pukala TL; Department of Chemistry, School of Physics, Chemistry and Earth Sciences, The University of Adelaide, Australia., Rijs NJ; School of Chemistry, UNSW Sydney, Sydney, NSW, 2052, Australia. n.rijs@unsw.edu.au. |
| Abstrakt: |
Small differences in the structure and subsequent reactivity of glyphosate complexes can have a highly consequential impact due to the enormous quantities of glyphosate used globally. The gas phase metal speciation of glyphosate and its abundant metabolite, aminomethylphosphonic acid (AMPA), were determined using cross-platform electrospray ionisation ion mobility mass spectrometry. Monomeric [M + L - H] + complexes, and both larger, and/or higher order clusters formed with divalent metals (M = Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ , Mn 2+ , Co 2+ , Cu 2+ , and Zn 2+ ; and L = glyphosate and AMPA). Complexation occurred at more than one ligand donor site for [M + L - H] + , resulting in multidentate complexes. The type of complex depended on M, with central positions maximizing the interactions of the M with donor sites of the L preferred. The isomers were separated by ion mobility and experimental collisional cross sections ( N2 CCS exp ) were derived for all isolated species. An energy threshold DFT approach located the structural families and potential lowest energy forms; these were found to be consistent with confirmed condensed phase (reported crystal structures) and gas phase structures ( via infrared multiple photon dissociation, IRMPD). Theoretical nitrogen collisional cross sections ( N2 CCS calc ) of these confirmed structures tended to underestimate the N2 CCS exp for both [M + glyphosate - H] + and [M + AMPA - H] + complexes. Underestimation ranged between 1-20%, and was not uniform between species. By comparison, helium collisional cross sections ( He CCS exp and He CCS calc ) were in better agreement (within 1-3%). These findings suggest further refinements are needed to collisional cross section modelling for metal containing species, in particular for nitrogen drift gas. |
