title: IR-MALDI ion mobility spectrometry.
abstract: The novel combination of infrared matrix-assisted laser dispersion and ionization (IR-MALDI) with ion mobility (IM) spectrometry makes it possible to investigate biomolecules in their natural environment, liquid water. As an alternative to an ESI source, the IR-MALDI source was implemented in an in-house-developed ion mobility (IM) spectrometer. The release of ions directly from an aqueous solution is based on a phase explosion, induced by the absorption of an IR laser pulse (λ = 2.94 μm, 6 ns pulse width), which disperses the liquid as nano- and micro-droplets. The prerequisites for the application of IR-MALDI-IM spectrometry as an analytical method are narrow analyte ion signal peaks for a high spectrometer resolution. This can only be achieved by improving the desolvation of ions. One way to full desolvation is to give the cluster ions sufficient time to desolvate. Two methods for achieving this are studied: the implementation of an additional drift tube, as in ESI-IM-spectrometry, and the delayed extraction of the ions. As a result of this optimization procedure, limits of detection between 5 nM and 2.5 μM as well as linear dynamic ranges of 2-3 orders of magnitude were obtained for a number of substances. The ability of this method to analyze simple mixtures is illustrated by the separation of two different surfactant mixtures.
authors.affiliation: Physical Chemistry, University of Potsdam, Karl-Liebknecht-Straße 24-25, 14476, Potsdam, Germany. jvillato@uni-potsdam.de.|BAM Federal Institute for Materials Research and Testing, Richard-Willstätter-Straße 11, 12489, Berlin, Germany. jvillato@uni-potsdam.de.|School of Analytical Sciences Adlershof (SALSA), Humboldt-Universität zu Berlin, Adlershof, Unter den Linden 6, 10099, Berlin, Germany. jvillato@uni-potsdam.de.
authors.forename: José
authors.identifier: http://orcid.org/0000-0001-7512-1497
authors.initials: J
authors.lastname: Villatoro
authors.affiliation: Physical Chemistry, University of Potsdam, Karl-Liebknecht-Straße 24-25, 14476, Potsdam, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Zühlke
authors.affiliation: Physical Chemistry, University of Potsdam, Karl-Liebknecht-Straße 24-25, 14476, Potsdam, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Riebe
authors.affiliation: BAM Federal Institute for Materials Research and Testing, Richard-Willstätter-Straße 11, 12489, Berlin, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Riedel
authors.affiliation: Physical Chemistry, University of Potsdam, Karl-Liebknecht-Straße 24-25, 14476, Potsdam, Germany.
authors.forename: Toralf
authors.initials: T
authors.lastname: Beitz
authors.affiliation: Physical Chemistry, University of Potsdam, Karl-Liebknecht-Straße 24-25, 14476, Potsdam, Germany.
authors.forename: Hans-Gerd
authors.initials: HG
authors.lastname: Löhmannsröben
mesh_terms: D004867:Equipment Design; D007259:Infrared Rays; D000075663:Ion Mobility Spectrometry / Q000295:instrumentation* / Q000379:methods; D007477:Ions / Q000737:chemistry; D007834:Lasers; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000295:instrumentation* / Q000379:methods
chemical_list: D007477:Ions
keywords: IR-MALDI; Ion mobility spectrometry; Laser