title: Spatially resolved investigation of systemic and contact pesticides in plant material by desorption electrospray ionization mass spectrometry imaging (DESI-MSI).
abstract: Distribution of pesticides both on the surface of leaves and in cross sections of plant stem and leaves was investigated using desorption electrospray ionization mass spectrometry imaging (DESI-MSI) with a spatial resolution of 50-100 μm. Two commercially available insecticide sprays containing different contact pesticides were applied onto leaves of Cotoneaster horizontalis, and the distributions of all active ingredients were directly analyzed. The first spray contained pyrethrins and rapeseed oil, both known as natural insecticides. Each component showed an inhomogeneous spreading throughout the leaf, based on substance polarity and solubility. The second spray contained the synthetic insecticides imidacloprid and methiocarb. Imidacloprid accumulated on the border of the leaf, while methiocarb was distributed more homogenously. In order to investigate the incorporation of a systemically acting pesticide into Kalanchoe blossfeldiana, a commercially available insecticide tablet containing dimethoate was spiked to the soil of the plant. Cross sections of the stem and leaf were obtained 25 and 60 days after application. Dimethoate was mainly detected in the transport system of the plant after 25 days, while it was found to be homogenously distributed in a leaf section after 60 days.
authors.affiliation: Institute of Inorganic and Analytical Chemistry, Justus Liebig University, Schubertstraße 60, 35392, Giessen, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Gerbig
authors.affiliation: Landesbetrieb Hessisches Landeslabor, Schubertstraße 60, 35392, Giessen, Germany.
authors.forename: Hubertus E
authors.initials: HE
authors.lastname: Brunn
authors.affiliation: Institute of Inorganic and Analytical Chemistry, Justus Liebig University, Schubertstraße 60, 35392, Giessen, Germany.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Spengler
authors.affiliation: Institute of Inorganic and Analytical Chemistry, Justus Liebig University, Schubertstraße 60, 35392, Giessen, Germany. Sabine.Schulz@anorg.Chemie.uni-giessen.de.
authors.forename: Sabine
authors.initials: S
authors.lastname: Schulz
mesh_terms: D013058:Mass Spectrometry / Q000379:methods*; D010575:Pesticides / Q000032:analysis*; D018515:Plant Leaves / Q000737:chemistry*
chemical_list: D010575:Pesticides
keywords: Ambient ionization; Desorption electrospray ionization; Imaging mass spectrometry; In situ analysis; Pesticides