title: Direct Imaging Mass Spectrometry of Plant Leaves Using Surface-assisted Laser Desorption/Ionization with Sputter-deposited Platinum Film.
abstract: Plant leaves administered with systemic insecticides as agricultural chemicals were analyzed using imaging mass spectrometry (IMS). Matrix-assisted laser desorption/ionization (MALDI) is inadequate for the detection of insecticides on leaves because of the charge-up effect that occurs on the non-conductive surface of the leaves. In this study, surface-assisted laser desorption/ionization with a sputter-deposited platinum film (Pt-SALDI) was used for direct analysis of chemicals in plant leaves. Sputter-deposited platinum (Pt) films were prepared on leaves administered with the insecticides. A sputter-deposited Pt film with porous structure was used as the matrix for Pt-SALDI. Acephate and acetamiprid contained in the insecticides on the leaves could be detected using Pt-SALDI-MS, but these chemical components could not be adequately detected using MALDI-MS because of the charge-up effect. Enhancement of ion yields for the insecticides was achieved using Pt-SALDI, accompanied by prevention of the charge-up effect by the conductive Pt film. The movement of systemic insecticides in plants could be observed clearly using Pt-SALDI-IMS. The distribution and movement of components of systemic insecticides on leaves could be analyzed directly using Pt-SALDI-IMS. Additionally, changes in the properties of the chemicals with time, as an indicator of the permeability of the insecticides, could be evaluated.
authors.affiliation: Department of Chemistry and Materials Engineering, Faculty of Chemistry, Materials, and Bioengineering, Kansai University.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Ozawa
authors.forename: Issey
authors.initials: I
authors.lastname: Osaka
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hamada
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Murakami
authors.forename: Akio
authors.initials: A
authors.lastname: Miyazato
authors.forename: Hideya
authors.initials: H
authors.lastname: Kawasaki
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Arakawa
mesh_terms: D002623:Chemistry Techniques, Analytical / Q000379:methods*; D007306:Insecticides / Q000032:analysis*; D018515:Plant Leaves / Q000737:chemistry*; D010984:Platinum / Q000737:chemistry*; D059629:Signal-To-Noise Ratio; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D007306:Insecticides; D010984:Platinum