title: A sample preparation method for recovering suppressed analyte ions in MALDI TOF MS.
abstract: In matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS), analyte signals can be substantially suppressed by other compounds in the sample. In this technical note, we describe a modified thin-layer sample preparation method that significantly reduces the analyte suppression effect (ASE). In our method, analytes are deposited on top of the surface of matrix preloaded on the MALDI plate. To prevent embedding of analyte into the matrix crystals, the sample solution were prepared without matrix and efforts were taken not to re-dissolve the preloaded matrix. The results with model mixtures of peptides, synthetic polymers and lipids show that detection of analyte ions, which were completely suppressed using the conventional dried-droplet method, could be effectively recovered by using our method. Our findings suggest that the incorporation of analytes in the matrix crystals has an important contributory effect on ASE. By reducing ASE, our method should be useful for the direct MALDI MS analysis of multicomponent mixtures.
authors.affiliation: Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands.
authors.forename: Xianwen
authors.initials: X
authors.lastname: Lou
authors.affiliation: Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands.
authors.forename: Bas F M
authors.initials: BF
authors.lastname: de Waal
authors.affiliation: Laboratory of Chemical Biology and Institute of Complex Molecular Systems (ICMS), Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands.
authors.forename: Lech-Gustav
authors.initials: LG
authors.lastname: Milroy
authors.affiliation: Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands.
authors.forename: Joost L J
authors.initials: JL
authors.lastname: van Dongen
mesh_terms: D007477:Ions / Q000032:analysis* / Q000737:chemistry*; D008055:Lipids / Q000737:chemistry; D008956:Models, Chemical; D010455:Peptides / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D007477:Ions; D008055:Lipids; D010455:Peptides; D011108:Polymers
keywords: MALDI TOF MS; modified thin-layer method; recovery; sample preparation method; suppressed analyte ions