title: The application of ToF-SIMS to the analysis of herbicide formulation penetration into and through leaf cuticles.
abstract: Understanding the movement of the active ingredient in relation to the other formulation components following application is crucial to an overall understanding of herbicide performance. We describe the novel use of time-of-flight secondary ion mass spectrometry (ToF-SIMS) as a tool for following the movement of herbicide formulation components into and across plant cuticles. This technique provides new insights since it provides both high (sub-micron) spatial resolution combined with the chemical specificity associated with organic mass spectrometry. The components studied include the oligomeric ethoxylate surfactants Synperonic A7 and A20 and active ingredient Sulfosate (trimesium glyphosate). The movement of these molecules, both separately and when combined in a simple formulation, into the surface of Prunus laurocerasus leaves and across the isolated plant cuticle was investigated and clear differences in penetration/diffusion behaviour were identified. ToF-SIMS was uniquely able to (simultaneously) spatially resolve all the species involved, including the anion and cation components of the active ingredient. Also, using spectral reconstructions from the imaging raw data streams, the behaviour of individual oligomers within the surfactant distributions, could be assessed. The observations are discussed with reference to the action of surfactants identified in parallel micro-structural studies and the current understanding of herbicide uptake.
authors.affiliation: Laboratory of Biophysics and Surface Analysis, School of Pharmacy, University of Nottingham, University Park, Nottingham NG7 2RD, UK. mperkins@molprofiles.co.uk
authors.forename: M C
authors.initials: MC
authors.lastname: Perkins
authors.forename: G
authors.initials: G
authors.lastname: Bell
authors.forename: D
authors.initials: D
authors.lastname: Briggs
authors.forename: M C
authors.initials: MC
authors.lastname: Davies
authors.forename: A
authors.initials: A
authors.lastname: Friedman
authors.forename: C A
authors.initials: CA
authors.lastname: Hart
authors.forename: C J
authors.initials: CJ
authors.lastname: Roberts
authors.forename: F J M
authors.initials: FJ
authors.lastname: Rutten
mesh_terms: D002851:Chromatography, High Pressure Liquid; D006540:Herbicides / Q000737:chemistry / Q000493:pharmacokinetics*; D018613:Microscopy, Confocal; D018515:Plant Leaves / Q000378:metabolism*; D027861:Prunus / Q000378:metabolism; D018629:Spectrometry, Mass, Secondary Ion
chemical_list: D006540:Herbicides