Parallel Operation of Electron Ionization and Chemical Ionization for GC-MS Using a Single TOF Mass Analyzer.

This work describes a novel mass spectrometer coupled to gas chromatography (GC-MS) that simultaneously displays the mass spectral information of electron (EI)- and chemical ionization (CI)-generated ion populations for a single chromatographic peak. After GC separation, the eluent is equally split and supplied in parallel to an EI and a novel CI source, both operating continuously. Precise switching of the ion optics provides the exact timing to consecutively extract the respective ion population from both sources and transfer them into a time-of-flight (TOF) mass analyzer.

Time-Of-Flight Mass Spectrometers Made in Switzerland: Examples of Mobile Applications.

Over the past decade, the technical requirements of analytical instrumentation have continuously risen driven by the demand for increasingly complex and demanding applications. TOFWERK, a Swiss company with the headquarters in Thun, has been at the forefront of this development by producing modular and ruggedized Time-Of-Flight Mass Spectrometers (TOFMS). They are often used to replace quadrupole mass analysers with more powerful TOF mass analysers.

Thermal Desorption-Vocus Enables Online Nondestructive Quantification of 2,4,6-Trichloroanisole in Cork Stoppers below the Perception Threshold.

2,4,6-Trichloroanisole (TCA) contamination of wine determines huge economic losses for the wine industry estimated to amount to several billion dollars yearly. Over 50 years of studies have determined that this problem is often caused by TCA contamination of the cork stopper, which releases TCA into the wine. The human threshold for TCA is extremely low.

Evaluation of a New Reagent-Ion Source and Focusing Ion-Molecule Reactor for Use in Proton-Transfer-Reaction Mass Spectrometry.

We evaluate the performance of a new chemical ionization source called Vocus, consisting of a discharge reagent-ion source and focusing ion-molecule reactor (FIMR) for use in proton-transfer-reaction time-of-flight mass spectrometry (PTR-TOF) measurements of volatile organic compounds (VOCs) in air. The reagent ion source uses a low-pressure discharge. The FIMR consists of a glass tube with a resistive coating, mounted inside a radio frequency (RF) quadrupole.

Improved resolution of hydrocarbon structures and constitutional isomers in complex mixtures using gas chromatography-vacuum ultraviolet-mass spectrometry.

Understanding the composition of complex hydrocarbon mixtures is important for environmental studies in a variety of fields, but many prevalent compounds cannot be confidently identified using traditional gas chromatography/mass spectrometry (GC/MS) techniques. This work uses vacuum-ultraviolet (VUV) ionization to elucidate the structures of a traditionally "unresolved complex mixture" by separating components by GC retention time, t(R), and mass-to-charge ratio, m/z, which are used to determine carbon number, N(C), and the number of rings and double bonds, N(DBE). Constitutional isomers are resolved on the basis of t(R), enabling the most complete quantitative analysis to date of structural isomers in an environmentally relevant hydrocarbon mixture.

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.

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.

Resistive glass IM-TOFMS.

The design of a new ion mobility mass spectrometer (IM-MS) is presented. This new design features an ambient-pressure resistive glass ion mobility drift tube (RGIMS) coupled to a high-resolution time-of-flight mass spectrometer (TOFMS) by an enhanced interface that includes two segmented quadrupoles. The interface design demonstrates an increase in sensitivity while maintaining high resolving power typically achieved for ambient-pressure IMS drift tubes.

Comprehensive multidimensional separation methods by hyphenation of single-photon ionization time-of-flight mass spectrometry (SPI-TOF-MS) with GC and GCxGC.

One- and comprehensive two-dimensional gas chromatography were hyphenated with soft photoionization mass spectrometry. The characteristics of these two- and three-dimensional comprehensive separation techniques are discussed in detail. Using the innovative electron beam pumped excimer light source (EBEL) for single-photon ionization (SPI), organic molecules with ionization energies (E ( i )) of below 9.

An ion trap-ion mobility-time of flight mass spectrometer with three ion sources for ion/ion reactions.

This instrument combines the capabilities of ion/ion reactions with ion mobility (IM) and time-of-flight (TOF) measurements for conformation studies and top-down analysis of large biomolecules. Ubiquitin ions from either of two electrospray ionization (ESI) sources are stored in a three dimensional (3D) ion trap (IT) and reacted with negative ions from atmospheric sampling glow discharge ionization (ASGDI). The proton transfer reaction products are then separated by IM and analyzed via a TOF mass analyzer.

Development and characterization of an aircraft aerosol time-of-flight mass spectrometer.

Vertical and horizontal profiles of atmospheric aerosols are necessary for understanding the impact of air pollution on regional and global climate. To gain further insight into the size-resolved chemistry of individual atmospheric particles, a smaller aerosol time-of-flight mass spectrometer (ATOFMS) with increased data acquisition capabilities was developed for aircraft-based studies. Compared to previous ATOFMS systems, the new instrument has a faster data acquisition rate with improved ion transmission and mass resolution, as well as reduced physical size and power consumption, all required advances for use in aircraft studies.

Performance, resolving power, and radial ion distributions of a prototype nanoelectrospray ionization resistive glass atmospheric pressure ion mobility spectrometer.

In this article, we describe and characterize a novel ion mobility spectrometer constructed with monolithic resistive glass desolvation and drift regions. This instrument is equipped with switchable corona discharge and nanoelectrospray ionization sources and a Faraday plate detector. Following description of the instrument, pulsing electronics, and data acquisition system, we examine the effects of drift gas flow rate and temperature, and of the aperture grid to anode distance on the observed resolving power and sensitivity.

Field-deployable, high-resolution, time-of-flight aerosol mass spectrometer.

The development of a new high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) is reported. The high-resolution capabilities of this instrument allow the direct separation of most ions from inorganic and organic species at the same nominal m/z, the quantification of several types of organic fragments (CxHy, CxHyOz, CxHyNp, CxHyOzNp), and the direct identification of organic nitrogen and organosulfur content. This real-time instrument is field-deployable, and its high time resolution (0.

Evaluation of a pulsed glow discharge time-of-flight mass spectrometer as a detector for gas chromatography and the influence of the glow discharge source parameters on the information volume in chemical speciation analysis.

The figures of merit of a pulsed glow discharge time-of-flight mass spectrometer (GD-TOFMS) as a detector for gas chromatography (GC) analysis were evaluated. The mass resolution for the GD-TOFMS was determined on FWHM in the high mass range (208Pb+) as high as 5,500. Precision of 400 subsequent analyses was calculated on 63Cu+ to be better than 1% RSD with no significant drift over the time of the analysis.

Lipid/peptide/nucleotide separation with MALDI-ion mobility-TOF MS.

Matrix-assisted laser desorption/ionization when combined with ion mobility-orthogonal time-of-flight mass spectrometry is a viable technique for fast separation and analysis of biomolecules in complex mixtures. Isobaric lipid, peptide, and oligonucleotide ions are preseparated before mass analysis by differences of up to 30% in mobility drift time. Ions of similar chemical type fall along well-defined "trend lines" (with deviations of approximately 3%) when plotted in two-dimensional representations of ion mobility as a function of m/z.

A resonant electron capture time-of-flight MS with trochoidal electron monochromator.

A prototype electron monochromator (EM) reflectron time-of-flight (TOF) mass spectrometer has been constructed and demonstrated to record resonant electron capture (REC) mass spectra of electron-capturing compounds. The electron energy is ramped from -1.7 to +25 eV at a preset frequency, and the energy spread of the electron beam at 15 nA is 100 meV or better.

Angiotensin II-acetylcholine noncovalent complexes analyzed with MALDI-ion mobility-TOF MS.

Matrix-assisted laser desorption ionization-ion mobility-orthogonal time-of-flight mass spectrometry (MALDI-IM oTOF MS) is a new technique that allows laser desorbed ion to be preseparated on the basis of their shape prior to mas analysis. Using this instrument, we tested the postulate that addition of a quaternary ammonium compound such as acetylcholine to the model phosphorylated peptide angio tensin II would enhance its detection by MALDI in two ways. First of all, the acetylcholine-peptide complex could ionize more efficiently than the bare phosphopeptide.

Oligonucleotide analysis with MALDI-ion-mobility-TOFMS.

Matrix-assisted laser-desorption ionization followed by ion-mobility separation and time-of-flight mass analysis (MALDI-IM-TOFMS) has been used to characterize native and chemically modified DNA oligonucleotides up to eight bases in length. Mobility resolution between 20 and 30 can be used to separate oligonucleotides of different length, but not to differentiate between isomers or even different compositions of the same length. MALDI-IM-TOFMS does, however, have additional utility in the analysis of mixtures of DNA oligonucleotides and peptides, because these classes of molecules can be distinguished on the basis of differences in their mobility.

A study of peptide-peptide interactions using MALDI ion mobility o-TOF and ESI mass spectrometry.

Matrix-assisted laser desorption ionization ion mobility coupled to orthogonal time-of-flight mass spectrometry (MALDI-IM-oTOF MS) is evaluated as a tool for studying non-covalent complex (NCX) formation between peptides. The NCX formed between dynorphin 1-7 and Mini Gastrin I is used as a model system for comparison to previous MALDI experiments (Woods, A. S.