title: Role of electrons in laser desorption/ionization mass spectrometry.
abstract: A nonmetallic sample support for matrix-assisted laser desorption/ionization (MALDI) mass spectrometry enhances the positive ion yield by 2 orders of magnitude and generally affects the charge balance in the desorption plume. We interpret the effects of the target material and of the sample preparation on MALDI mass spectra as a result of photoelectrons emitted upon laser irradiation of a metal target covered by a thin sample layer. These electrons are shown to play an important role in MALDI and laser desorption/ionization because they decrease the yield of positive ions, reduce ions with higher oxidation states, and affect the ion velocity distribution as well as the mass resolution. Understanding the role of these photoelectrons helps to clarify previously obscure aspects of the ion formation mechanism in MALDI.
authors: Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology (ETH), Zürich, ETH-Hönggerberg, CH-8093 Zürich, Switzerland.
authors: Vladimir E
authors: VE
authors: Frankevich
authors: Juan
authors: J
authors: Zhang
authors: Sebastian D
authors: SD
authors: Friess
authors: Maxim
authors: M
authors: Dashtiev
authors: Renato
authors: R
authors: Zenobi
mesh_terms: D000818:Animals; D001920:Bradykinin / Q000737:chemistry; D002417:Cattle; D004583:Electrons; D005841:Gentisates / Q000737:chemistry; D012710:Serum Albumin, Bovine / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D005841:Gentisates; D012710:Serum Albumin, Bovine; D001920:Bradykinin; C010925:2,5-dihydroxybenzoic acid