title: Quasi-simultaneous acquisition of hard electron ionization and soft single-photon ionization mass spectra during GC/MS analysis by rapid switching between both ionization methods: analytical concept, setup, and application on diesel fuel.
abstract: This work describes the realization of rapid switching between hard electron ionization (EI) and soft single-photon ionization (SPI) integrated in a compact orthogonal acceleration time-of-flight mass spectrometer. Vacuum-ultraviolet (VUV) photons of 9.8 eV (126 nm) emitted from the innovative electron-beam-pumped rare-gas excimer light source (EBEL) filled with argon are focused into the ion chamber by an ellipsoidal mirror optic for accomplishing of SPI. This novel orthogonal acceleration time-of-flight mass spectrometer with switching capability was hyphenated to one-dimensional gas chromatography (GC) and comprehensive two-dimensional (2D) gas chromatography (GC × GC) for the first time. Within this demonstration study, a maximum switching frequency of 80 Hz was applied for investigation of a mineral-oil-type diesel sample. This approach allows the quasi-simultaneous acquisition of complementary information about the fragmentation pattern (EI) as well as the molecular mass (SPI) of compounds within a single analysis. Furthermore, by application of a polar GC column for separation, the SPI data can be displayed in a 2D contour plot, leading to a comprehensive 2D characterization (GC × MS), whereas the typical group-type assignment for diesel is also met.
authors.affiliation: Joint Mass Spectrometry Centre, Cooperation Group Analysis of Complex Molecular Systems, Institute of Ecological Chemistry, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany.
authors.forename: Markus S
authors.initials: MS
authors.lastname: Eschner
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Gröger
authors.forename: Thomas
authors.initials: T
authors.lastname: Horvath
authors.forename: Marc
authors.initials: M
authors.lastname: Gonin
authors.forename: Ralf
authors.initials: R
authors.lastname: Zimmermann
mesh_terms: D001128:Argon / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry / Q000295:instrumentation / Q000379:methods*; D005742:Gasoline / Q000032:analysis*; D017785:Photons
chemical_list: D005742:Gasoline; D001128:Argon