New Processes for Ionizing Nonvolatile Compounds in Mass Spectrometry: The Road of Discovery to Current State-of-the-Art.

This covers discovery and mechanistic aspects as well as initial applications of novel ionization processes for use in mass spectrometry that guided us in a series of subsequent discoveries, instrument developments, and commercialization. matrix-assisted ionization on an intermediate pressure matrix-assisted laser desorption/ionization source the use of a laser, high voltages, or any other added energy was simply unbelievable, at first. Individually and as a whole, the various discoveries and inventions started to paint, , an exciting new picture and outlook in mass spectrometry from which key developments grew that were at the time unimaginable, and continue to surprise us in its simplistic preeminence.

Instrumentation development, improvement, simplification, and miniaturization: The multifunctional plate source for use in mass spectrometry.

In remembrance of Prof. Dr Przybylski, we are presenting a vision towards his beloved mass spectrometry (MS) and its far-reaching promises outside of the academic laboratory. Sub-atmospheric pressure (AP) ionization MS is well positioned to make a step-change in direct ionization, a concept that allows ionization and mass analyses of volatile and nonvolatile molecules from clean or dirty samples, directly, accurately, sensitively, and in a straightforward manner that has the potential to expand the field of MS into unchartered application areas.

Sublimation Driven Ionization for Use in Mass Spectrometry: Mechanistic Implications.

Sublimation has been known at least since the middle ages. This process is frequently taught in schools through the use of phase diagrams. Astonishingly, such a well-known process appears to still harbor secrets.

Expression and Characterization of the Antimicrobial Peptide Oncocin and Variants Binding to Ribosomes.

Peptides have important biomedical applications, but poor correlation between and activities can limit their development for clinical use. The ability to generate peptides and monitor their expression with new mass spectrometric methods and biological activities would be an advantage for the discovery and improvement of peptide-based drugs. In this study, a plasmid-based system was used to express the ribosome-targeting peptide oncocin (19 amino acids, VDKPPYLPRPRPPRRIYNR) and to determine its direct antibacterial effects on Previous biochemical and structure studies showed that oncocin targets the bacterial ribosome.

Resolving Isomers of Star-Branched Poly(Ethylene Glycols) by IMS-MS Using Multiply Charged Ions.

Ion mobility spectrometry (IMS) mass spectrometry (MS) centers on the ability to separate gaseous structures by size, charge, shape, and followed by mass-to-charge (/). For oligomeric structures, improved separation is hypothesized to be related to the ability to extend structures through repulsive forces between cations electrostatically bonded to the oligomers. Here we show the ability to separate differently branched multiply charged ions of star-branched poly(ethylene glycol) oligomers (up to 2000 Da) regardless of whether formed by electrospray ionization (ESI) charged solution droplets or from charged solid particles produced directly from a surface by matrix-assisted ionization.

Comparison of gaseous ubiquitin ion structures obtained from a solid and solution matrix using ion mobility spectrometry/mass spectrometry.

Rationale: Examining surface protein conformations, and especially achieving this with spatial resolution, is an important goal. The recently discovered ionization processes offer spatial-resolution measurements similar to matrix-assisted laser desorption/ionization (MALDI) and produce charge states similar to electrospray ionization (ESI) extending higher-mass protein applications directly from surfaces on high-performance mass spectrometers. Studying a well-interrogated protein by ion mobility spectrometry-mass spectrometry (IMS-MS) to access effects on structures using a solid vs.

New mass spectrometry concepts for characterization of synthetic polymers and additives.

Rationale: New ionization processes have been developed for biological mass spectrometry (MS) in which the matrix lifts the nonvolatile analyte into the gas phase as ions without any additional energy input. We rationalized that additional fundamental knowledge is needed to assess analytical utility for the field of synthetic polymers and additives.

Methods: Different mass spectrometers (Thermo Orbitrap (Q-)Exactive (Focus); Waters SYNAPT G2(S)) were employed.

Toward understanding the ionization mechanism of matrix-assisted ionization using mass spectrometry experiment and theory.

Rationale: Matrix-assisted ionization (MAI) mass spectrometry does not require voltages, a laser beam, or added heat to initiate ionization, but it is strongly dependent on the choice of matrix and the vacuum conditions. High charge state distributions of nonvolatile analyte ions produced by MAI suggest that the ionization mechanism may be similar to that of electrospray ionization (ESI), but different from matrix-assisted laser desorption/ionization (MALDI). While significant information is available for MAI using mass spectrometers operating at atmospheric and intermediate pressure, little is known about the mechanism at high vacuum.

Unprecedented Ionization Processes in Mass Spectrometry Provide Missing Link between ESI and MALDI.

In the field of mass spectrometry, producing intact, highly-charged protein ions from surfaces is a conundrum with significant potential payoff in application areas ranging from biomedical to clinical research. Here, we report on the ability to form intact, highly-charged protein ions on high vacuum time-of-flight mass spectrometers in the linear and reflectron modes achievable using experimental conditions that allow effective matrix removal from both the sample surfaces and from the charged clusters formed by the laser ablation event. The charge states are the highest reported on high vacuum mass spectrometers, yet they remain at only around a third of the highest charge obtained using laser ablation with a suitable matrix at atmospheric pressure.

Spontaneous Charge Separation and Sublimation Processes are Ubiquitous in Nature and in Ionization Processes in Mass Spectrometry.

Ionization processes have been discovered by which small and large as well as volatile and nonvolatile compounds are converted to gas-phase ions when associated with a matrix and exposed to sub-atmospheric pressure. Here, we discuss experiments further defining these simple and unexpected processes. Charge separation is found to be a common process for small molecule chemicals, solids and liquids, passed through an inlet tube from a higher to a lower pressure region, with and without heat applied.

From common to rare Zingiberaceae plants - A metabolomics study using GC-MS.

Zingiberaceae plants, commonly known as gingers, have been popular for their medicinal and culinary uses since time immemorial. In spite of their numerous health-promoting applications, many Zingiberaceae plants still receive no scientific attention. Moreover, existing reports mostly focused only on the Zingiberaceae rhizomes.

Rapid high mass resolution mass spectrometry using matrix-assisted ionization.

Matrix-assisted ionization (MAI) is demonstrated to be a robust and sensitive analytical method capable of analyzing proteins such as cholera toxin B-subunit and pertussis toxin mutant from conditions containing relatively high amounts of inorganic salts, buffers, and preservatives without the need for prior sample clean-up or concentration. By circumventing some of the sample preparation steps, MAI simplifies and accelerates the analytical workflow for biological samples in complex media. The benefits of multiply charged ions characteristic of electrospray ionization (ESI) and the robustness of matrix-assisted laser desorption/ionization (MALDI) can be obtained from a single method, making it well suited for analysis of proteins and other biomolecules at ultra-high resolution as demonstrated on an Orbitrap Fusion where protein subunits were resolved for which MALDI-time-of-flight failed.

High-throughput characterization of small and large molecules using only a matrix and the vacuum of a mass spectrometer.

Matrix assisted ionization vacuum (MAIV) rapidly generates gas-phase analyte ions from subliming solid-phase matrix:analyte crystals for analysis by mass spectrometry (MS). Ionization from the solid-phase allows the use of a variety of surfaces for introducing matrix:analyte samples to the vacuum of a mass spectrometer, including common laboratory materials, such as disposable pipet tips, filter paper, tooth picks, and nylon mesh. MAIV is shown here to be capable of analyses as fast as 3 s per sample with achievable sensitivities in the low femtomole range.

Transmission geometry laserspray ionization vacuum using an atmospheric pressure inlet.

This represents the first report of laserspray ionization vacuum (LSIV) with operation directly from atmospheric pressure for use in mass spectrometry. Two different types of electrospray ionization source inlets were converted to LSIV sources by equipping the entrance of the atmospheric pressure inlet aperture with a customized cone that is sealed with a removable glass plate holding the matrix/analyte sample. A laser aligned in transmission geometry (at 180° relative to the inlet) ablates the matrix/analyte sample deposited on the vacuum side of the glass slide.

Toward high spatial resolution sampling and characterization of biological tissue surfaces using mass spectrometry.

Mass spectrometry has emerged as a powerful tool for the bioanalytical sciences because of its ability to characterize small and large biomolecules in vanishingly small amounts. A recurring motif in mass spectrometry aims to decipher the chemical composition of biological samples at the molecular level, requiring drastic improvements in the ability to interrogate well defined and highly spatially resolved areas of a sample surface. With the growth of novel ionization methods, numerous advances have been made in sampling biological tissue surfaces.

A new matrix assisted ionization method for the analysis of volatile and nonvolatile compounds by atmospheric probe mass spectrometry.

Matrix assisted ionization of nonvolatile compounds is shown not to be limited to vacuum conditions and does not require a laser. Simply placing a solution of analyte dissolved with a suitable matrix such as 3-nitrobenzonitrile (3-NBN) or 2,5-dihydroxyacetophenone on a melting point tube and gently heating the dried sample near the ion entrance aperture of a mass spectrometer using a flow of gas produces abundant ions of peptides, small proteins, drugs, and polar lipids. Fundamental studies point to matrix-mediated ionization occurring prior to the entrance aperture of the mass spectrometer.

Matrix assisted ionization in vacuum, a sensitive and widely applicable ionization method for mass spectrometry.

An astonishingly simple new method to produce gas-phase ions of small molecules as well as proteins from the solid state under cold vacuum conditions is described. This matrix assisted ionization vacuum (MAIV) mass spectrometry (MS) method produces multiply charged ions similar to those that typify electrospray ionization (ESI) and uses sample preparation methods that are nearly identical to matrix-assisted laser desorption/ionization (MALDI). Unlike these established methods, MAIV does not require a laser or voltage for ionization, and unlike the recently introduced matrix assisted ionization inlet method, does not require added heat.

Laserspray and matrix-assisted ionization inlet coupled to high-field FT-ICR mass spectrometry for peptide and protein analysis.

We present the first coupling of laser spray ionization inlet (LSII) and matrix assisted ionization inlet (MAII) to high-field Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) for generation of electrospray-like ions to take advantage of increased sensitivity, mass range, and mass resolving power afforded by multiple charging. We apply the technique to top-down protein analysis and characterization of metalloproteins. We also present a novel method for generation of multiply-charged copper-peptide complexes with varying degrees of copper adduction by LSII.