1
|
Alinezhad V, Ng YK, Mehta S, Konermann L. Uncovering the Pathway of Serine Octamer Magic Number Cluster Formation during Electrospray Ionization: Experiments and Simulations. J Am Chem Soc 2024; 146:26726-26742. [PMID: 39287424 DOI: 10.1021/jacs.4c05760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/19/2024]
Abstract
Electrospray ionization (ESI) of serine (Ser) solution generates Ser8H+ as an abundant magic number cluster. ESI clustering of most other solutes yields nonspecific stoichiometries. It is unclear why Ser8H+ dominates in the case of Ser, and how Ser8H+ forms during ESI. Even the location of Ser8H+ formation is contentious (in solution, in ESI droplets, or elsewhere). Here we unravel key aspects of the l-Ser8H+ formation pathway. Harsh ion sampling conditions promote the collision-induced dissociation (CID) of regular ESI analytes. Unexpectedly, Ser8H+ was seemingly resistant against CID during ion sampling, despite its extremely low tandem mass spectrometry (MS/MS) stability. This unusual behavior reveals that Ser8H+ forms during ion sampling. We propose the following pathway: (1) Nonspecific Ser clusters are released when ESI droplets evaporate to dryness. These initial clusters cover a wide size range, from a few Ser to hundreds or thousands of monomers. (2) The clusters undergo dissociation during ion sampling, mostly via successive loss of neutral monomers. For any source activation voltage, there is a subpopulation of clusters for which this CID cascade tends to terminate at the octamer level, culminating in Ser8H+-dominated product distributions. Mobile proton molecular dynamics simulations were used to model the entire pathway. Ser8H+ structures formed in these simulations were consistent with ion mobility experiments. The most compact structures resembled the model of [Scutelnic, V. J. Am. Chem. Soc. 2018, 140, 7554-7560], with numerous intermolecular salt bridges and H-bonds. Our findings illustrate how the interplay of association and dissociation reactions across phase boundaries can culminate in magic number clusters.
Collapse
Affiliation(s)
- Vida Alinezhad
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Yuen Ki Ng
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Sanvid Mehta
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| |
Collapse
|
2
|
He X, Guo X, Deng F, Zeng P, Wu B, Sun H, Zhao Z, Duan Y. A study of the transient gas flow affected ion transmission in atmospheric pressure interfaces based on large eddy simulation for electrospray ionization mass spectrometry. Talanta 2024; 274:125980. [PMID: 38579418 DOI: 10.1016/j.talanta.2024.125980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 03/05/2024] [Accepted: 03/20/2024] [Indexed: 04/07/2024]
Abstract
Modern atmosphere pressure interface (API) enables high-efficiency coupling between mass analyzers in high vacuum and atmosphere ionization sources such as electrospray ionization (ESI) source. The transient gas flow entering API possesses strong compressibility and turbulent characteristics, which exerts a huge impact on ion transmission. However, the instantaneous nature and vortical morphology of the turbulence in API and its affection in ion transmission were hardly covered in the reported research. Here we conduct a transient turbulent flow-affected ion transmission evaluation for two typical APIs, the ion funnel and the S-lens, based on scale-resolving large eddy simulation and electro-hydrodynamical ion tracing simulation. In our simulation, the transient properties of the gas flow in the two APIs are illustrated and analyzed in-depth. After experimentally validated on a homemade ESI-TOF-MS platform, the results suggest that the ion funnel can achieve a higher droplet desolvation rate by introducing a unique droplet recirculation mechanism. Meanwhile, the less-dispersed gas flow in S-lens is beneficial in actuating ions axially. In conclusion, the application of the scale-resolving turbulence model helps us to understand the complicated fluid-ion interaction mechanism in APIs and is promising in the development of mass spectrometry instruments of higher performance.
Collapse
Affiliation(s)
- Xingliang He
- Research Center of Analytical Instrumentation, School of Mechanical Engineering, Sichuan University, China
| | - Xing Guo
- Research Center of Analytical Instrumentation, School of Mechanical Engineering, Sichuan University, China
| | - Fulong Deng
- Research Center of Analytical Instrumentation, School of Mechanical Engineering, Sichuan University, China
| | - Pengyu Zeng
- Research Center of Analytical Instrumentation, School of Mechanical Engineering, Sichuan University, China
| | - Bin Wu
- Research Center of Analytical Instrumentation, School of Mechanical Engineering, Sichuan University, China
| | - Hong'en Sun
- Research Center of Analytical Instrumentation, School of Mechanical Engineering, Sichuan University, China
| | - Zhongjun Zhao
- Research Center of Analytical Instrumentation, School of Mechanical Engineering, Sichuan University, China; Aliben Science & Technology, China.
| | - Yixiang Duan
- Research Center of Analytical Instrumentation, School of Mechanical Engineering, Sichuan University, China; Aliben Science & Technology, China.
| |
Collapse
|
3
|
Hanifi K, Scrosati PM, Konermann L. MD Simulations of Peptide-Containing Electrospray Droplets: Effects of Parameter Settings on the Predicted Mechanisms of Gas Phase Ion Formation. J Phys Chem B 2024; 128:5973-5986. [PMID: 38864851 DOI: 10.1021/acs.jpcb.4c01241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2024]
Abstract
Electrospray ionization (ESI) mass spectrometry is widely used for interrogating peptides, proteins, and other biomolecular analytes. A growing number of laboratories use molecular dynamics (MD) simulations for uncovering ESI mechanisms by modeling the behavior of highly charged nanodroplets. The outcome of any MD simulation depends on certain assumptions and parameter settings, and it is desirable to optimize these factors by benchmarking computational data against experiments. Unfortunately, benchmarking of ESI simulations is difficult because experimentally generated gaseous ions do not generally retain any features that would reveal their formation pathway [e.g., the charged residue mechanism (CRM) or the ion evaporation mechanism (IEM)]. Here, we tackle this problem by examining the effects of various MD settings on the ESI behavior of the 9-residue peptide bradykinin in acidic aqueous droplets. Several parameters were found to significantly affect the kinetic competition between peptide IEM and CRM. By systematically probing the droplet behavior, we uncovered problems associated with certain settings, including peptide/solvent temperature imbalances, unexpected peptide deceleration during IEM, and a dependence of the ESI mechanism on the water model. We also noted different simulation outcomes for different force fields. On the basis of comprehensive tests, we propose a set of "best practice" parameter settings for MD simulations of ESI droplets. The strategies used here should be transferable to other types of droplet simulations, paving the way toward a more solid understanding of ESI mechanisms.
Collapse
Affiliation(s)
- Kasra Hanifi
- Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7
| | - Pablo M Scrosati
- Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7
| | - Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7
| |
Collapse
|
4
|
Heintz C, Schnödewind L, Braubach O, Kersten H, Benter T, Wißdorf W. Observation of Large, Charged Droplet Signatures within the High-Vacuum Region of a Commercial Electrospray TOF-MS. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024; 35:508-517. [PMID: 38408762 DOI: 10.1021/jasms.3c00383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
Electrospray ionization (ESI) is one of the most prominent atmospheric pressure ionization techniques in modern mass spectrometry. It generates charged droplets from an analyte-containing solution as an initial step in the ionization process. Textbooks and the majority of the articles assume the entire droplet evaporation and release of bare analyte ions within the ionization chamber. However, non-mass-spectrometry-related literature and recent reports demonstrate droplet observation in regions of the vacuum systems of a variety of mass spectrometers. In this work, we report on the observation of large droplet fragments within the orthogonal acceleration stage of a Bruker micrOTOF by connecting an oscilloscope to an auxiliary ion current detector downstream of the acceleration stage. Moreover, we detected fragment debris even with the MCP TOF detector by evaluating individual TOF spectra. Droplet fragments appear as pronounced and intensive pulses of the ion current. This observation is clearly connected to ESI, as other atmospheric pressure ionization methods do not show this behavior. The recorded droplet signatures show clear dependencies on the ion source and transfer stage parameters. The existence of large and highly charged droplets may adversely affect or at least impact the analytical performance of the instrument due to space charge or complex heterogeneous chemical reactions. Furthermore, the penetration of large charged aggregates into the vacuum system explains the reported surface contamination after multipole stages. This contamination of critical components leads to substantially higher maintenance efforts.
Collapse
Affiliation(s)
- Chris Heintz
- Department of Physical and Theoretical Chemistry, University of Wuppertal, Gaussstraße 20, 42119 Wuppertal, Germany
| | - Lisa Schnödewind
- Department of Physical and Theoretical Chemistry, University of Wuppertal, Gaussstraße 20, 42119 Wuppertal, Germany
| | - Oliver Braubach
- Department of Physical and Theoretical Chemistry, University of Wuppertal, Gaussstraße 20, 42119 Wuppertal, Germany
| | - Hendrik Kersten
- Department of Physical and Theoretical Chemistry, University of Wuppertal, Gaussstraße 20, 42119 Wuppertal, Germany
| | - Thorsten Benter
- Department of Physical and Theoretical Chemistry, University of Wuppertal, Gaussstraße 20, 42119 Wuppertal, Germany
| | - Walter Wißdorf
- Department of Physical and Theoretical Chemistry, University of Wuppertal, Gaussstraße 20, 42119 Wuppertal, Germany
| |
Collapse
|
5
|
Tüshaus J, Sakhteman A, Lechner S, The M, Mucha E, Krisp C, Schlegel J, Delbridge C, Kuster B. A region-resolved proteomic map of the human brain enabled by high-throughput proteomics. EMBO J 2023; 42:e114665. [PMID: 37916885 PMCID: PMC10690467 DOI: 10.15252/embj.2023114665] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 10/16/2023] [Accepted: 10/17/2023] [Indexed: 11/03/2023] Open
Abstract
Substantial efforts are underway to deepen our understanding of human brain morphology, structure, and function using high-resolution imaging as well as high-content molecular profiling technologies. The current work adds to these approaches by providing a comprehensive and quantitative protein expression map of 13 anatomically distinct brain regions covering more than 11,000 proteins. This was enabled by the optimization, characterization, and implementation of a high-sensitivity and high-throughput microflow liquid chromatography timsTOF tandem mass spectrometry system (LC-MS/MS) capable of analyzing more than 2,000 consecutive samples prepared from formalin-fixed paraffin embedded (FFPE) material. Analysis of this proteomic resource highlighted brain region-enriched protein expression patterns and functional protein classes, protein localization differences between brain regions and individual markers for specific areas. To facilitate access to and ease further mining of the data by the scientific community, all data can be explored online in a purpose-built R Shiny app (https://brain-region-atlas.proteomics.ls.tum.de).
Collapse
Affiliation(s)
- Johanna Tüshaus
- Proteomics and Bioanalytics, Department of Molecular Life Sciences, School of Life SciencesTechnical University of MunichMunichGermany
| | - Amirhossein Sakhteman
- Proteomics and Bioanalytics, Department of Molecular Life Sciences, School of Life SciencesTechnical University of MunichMunichGermany
| | - Severin Lechner
- Proteomics and Bioanalytics, Department of Molecular Life Sciences, School of Life SciencesTechnical University of MunichMunichGermany
| | - Matthew The
- Proteomics and Bioanalytics, Department of Molecular Life Sciences, School of Life SciencesTechnical University of MunichMunichGermany
| | - Eike Mucha
- Bruker Daltonics GmbH & Co. KGBremenGermany
| | | | - Jürgen Schlegel
- Department of Neuropathology, Klinikum Rechts der ISAR, School of MedicineTechnical University MunichMunichGermany
| | - Claire Delbridge
- Department of Neuropathology, Klinikum Rechts der ISAR, School of MedicineTechnical University MunichMunichGermany
| | - Bernhard Kuster
- Proteomics and Bioanalytics, Department of Molecular Life Sciences, School of Life SciencesTechnical University of MunichMunichGermany
- German Cancer Consortium (DKTK), Munich SiteHeidelbergGermany
| |
Collapse
|
6
|
Bertrand E, Rondeau D, Delhaye T, Castel X, Himdi M. From electrospray ionization to cold-spray ionization: How to evaluate the cooling effect on the gaseous ions? JOURNAL OF MASS SPECTROMETRY : JMS 2023; 58:e4977. [PMID: 37903539 DOI: 10.1002/jms.4977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 09/21/2023] [Accepted: 09/26/2023] [Indexed: 11/01/2023]
Abstract
Two methods of survival yields (SY) measurement treatment of thermometer ions whose fragmentation is activated by in-source collision induced dissociation have been investigated for evaluating the mean internal () and thermal () energies of gaseous ions produced by electrospray ionization and cold-spray ionization (CSI). One of the methods is based on the use of the internal energy distributions (P (Eint )) as sigmoid derivatives connecting the experimental survival yields of different substituted benzylpyridinium cations. The values are therefore converted in a thermal-like parameter called vibrational temperature (Tvib ) then obtained at each value of the voltage of the desolvation area. The second method is based on the modelling of ion behavior by the MassKinetics software where the value of the characteristic temperature parameter (Tchar ) is used for fitting theoretical survival yields (SYtheo ) with experimental data (SYexp ) calculated at several activation energy. A linear correlation is evidenced between the values of internal or thermal energy and the voltage of the orifice 1 at the origin of the ion activation in the desolvation area. The extrapolation at zero voltage of the thermal-like parameters (Tvib and Tchar ) indicates that, in agreement with the literature data, the ions are relatively hot in ESI (~650 K). But the use of a CSI source lowers this temperature down to ~300 K. In addition, with cold-spray ionization, this cooling effect is more important when methanol is used instead of acetonitrile although these two solvents have no influence on the gaseous ion temperature in electrospray ionization.
Collapse
|
7
|
Lattouf E, Anttalainen O, Hecht O, Ungethüm B, Kotiaho T, Hakulinen H, Vanninen P, Eiceman G. Quantitative Distributions of Product Ions and Reaction Times with a Binary Mixture of VOCs in Ambient Pressure Chemical Ionization. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:1768-1777. [PMID: 37452772 PMCID: PMC10401699 DOI: 10.1021/jasms.3c00189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 07/04/2023] [Accepted: 07/10/2023] [Indexed: 07/18/2023]
Abstract
A model to quantitatively predict ion abundances from atmospheric pressure chemical ionization (APCI) between hydrated protons and a volatile organic compound (VOC) was extended to binary mixtures of VOCs. The model includes differences in vapor concentrations, rate coefficients, and reaction times and is enhanced with cross reactions between neutral vapors and protonated monomers. In this model, two specific VOCs were considered, a ketone, 6-methyl-5-hepten-2-one (M, and an amine, 2,6-di-tert-butyl-pyridine (N), with measured "conditional rate coefficients" (in cm3·s-1) of kM = 1.11 × 10-9 and kN = 9.17 × 10-10, respectively. The cross reaction of MH+(H2O)x to NH+(H2O)y was measured as kcr = 1.31 × 10-12 at 60 °C. Cross reactions showed an impact on ion abundances at t > 30 ms for equal vapor concentrations of 100 ppb for M and N. In contrast, this impact was negligible for vapor concentrations of 1 ppb and did not exceed 5% change in product ion abundance up to 1000 ms reaction times. The model was validated with laboratory measurements to within ∼10% using an ion mobility spectrometer and effective reaction time obtained from computational fitting of experimental findings. This was necessitated by complex flow patterns in the ion source volume and was determined as ∼10.5 ms. The model has interpretative and predictive value for quantitative analysis of responses with ambient pressure ion sources for mass spectrometry and ion mobility spectrometry.
Collapse
Affiliation(s)
- Elie Lattouf
- VERIFIN,
Finnish Institute for Verification of the Chemical Weapons Convention,
Department of Chemistry, University of Helsinki, FI-00014 Helsinki, Finland
| | - Osmo Anttalainen
- VERIFIN,
Finnish Institute for Verification of the Chemical Weapons Convention,
Department of Chemistry, University of Helsinki, FI-00014 Helsinki, Finland
| | - Oliver Hecht
- AIRSENSE
Analytics Gmbh, Hagenower
Straße 73, 19061 Schwerin, Germany
| | - Bert Ungethüm
- AIRSENSE
Analytics Gmbh, Hagenower
Straße 73, 19061 Schwerin, Germany
| | - Tapio Kotiaho
- Drug
Research Program and Division of Pharmaceutical Chemistry and Technology
and Department of Chemistry, University
of Helsinki, FI-00014 Helsinki, Finland
| | - Hanna Hakulinen
- VERIFIN,
Finnish Institute for Verification of the Chemical Weapons Convention,
Department of Chemistry, University of Helsinki, FI-00014 Helsinki, Finland
| | - Paula Vanninen
- VERIFIN,
Finnish Institute for Verification of the Chemical Weapons Convention,
Department of Chemistry, University of Helsinki, FI-00014 Helsinki, Finland
| | - Gary Eiceman
- VERIFIN,
Finnish Institute for Verification of the Chemical Weapons Convention,
Department of Chemistry, University of Helsinki, FI-00014 Helsinki, Finland
- New
Mexico State University, 1175 N Horseshoe Dr., Las Cruces, New Mexico 88003, United States
| |
Collapse
|
8
|
Kloudová B, Strmeň T, Vrkoslav V, Chára Z, Pačes O, Cvačka J. Gas Dynamic Virtual Nozzle Sprayer for an Introduction of Liquid Samples in Atmospheric Pressure Ionization Mass Spectrometry. Anal Chem 2023; 95:4196-4203. [PMID: 36800482 PMCID: PMC10016749 DOI: 10.1021/acs.analchem.2c05349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
Electrospray may exhibit inadequate ionization efficiency in some applications. In such cases, atmospheric-pressure chemical ionization (APCI) and photoionization (APPI) can be used. Despite a wide application potential, no APCI and APPI sources dedicated to very low sample flow rates exist on the market. Since the ion source performance depends on the transfer of analytes from the liquid to the gas phase, a nebulizer is a critical component of an ion source. Here, we report on the nebulizer with a gas dynamic virtual nozzle (GDVN) and its applicability in APCI at microliter-per-minute flow rates. Nebulizers differing by geometrical parameters were fabricated and characterized regarding the jet breakup regime, droplet size, droplet velocity, and spray angle for liquid flow rates of 0.75-15.0 μL/min. A micro-APCI source with the GDVN nebulizer behaved as a mass-flow-sensitive detector and provided stable and intense analyte signals. Compared to a classical APCI source, an order of magnitude lower detection limit for verapamil was achieved. Mass spectra recorded with the nebulizer in dripping and jetting modes were almost identical and did not differ from normal APCI spectra. Clogging never occurred during the experiments, indicating the high robustness of the nebulizer. Low-flow-rate APCI and APPI sources with a GDVN sprayer promise new applications for low- and medium-polar analytes.
Collapse
Affiliation(s)
- Barbora Kloudová
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, CZ-166 10 Prague 6, Czech Republic.,Department of Analytical Chemistry, Faculty of Science, Charles University in Prague, Hlavova 2030/8, CZ-128 43 Prague 2, Czech Republic
| | - Timotej Strmeň
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, CZ-166 10 Prague 6, Czech Republic
| | - Vladimír Vrkoslav
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, CZ-166 10 Prague 6, Czech Republic
| | - Zdeněk Chára
- Institute of Hydrodynamics of the Czech Academy of Sciences, Pod Pat'ankou 30/5, CZ-166 12 Prague 6, Czech Republic
| | - Ondřej Pačes
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, CZ-166 10 Prague 6, Czech Republic
| | - Josef Cvačka
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, CZ-166 10 Prague 6, Czech Republic.,Department of Analytical Chemistry, Faculty of Science, Charles University in Prague, Hlavova 2030/8, CZ-128 43 Prague 2, Czech Republic
| |
Collapse
|
9
|
Investigation of the applicability of silica-graphene hybrid materials as stationary phases for capillary liquid chromatography. J Chromatogr A 2022; 1685:463618. [DOI: 10.1016/j.chroma.2022.463618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 08/01/2022] [Accepted: 10/27/2022] [Indexed: 11/06/2022]
|
10
|
Konermann L, Haidar Y. Mechanism of Magic Number NaCl Cluster Formation from Electrosprayed Water Nanodroplets. Anal Chem 2022; 94:16491-16501. [DOI: 10.1021/acs.analchem.2c04141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Yousef Haidar
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| |
Collapse
|
11
|
Bhanot JS, Fabijanczuk KC, Abdillahi AM, Chao HC, Pizzala NJ, Londry FA, Dziekonski ET, Hager JW, McLuckey SA. Adaptation and Operation of a Quadrupole/Time-of-Flight Tandem Mass Spectrometer for High Mass Ion/Ion Reaction Studies. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 2022; 478:116874. [PMID: 37032994 PMCID: PMC10081487 DOI: 10.1016/j.ijms.2022.116874] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
A commercial quadrupole/time-of-flight tandem mass spectrometer has been modified and evaluated for its performance in conducting ion/ion reaction studies involving high mass (>100 kDa) ions. Modifications include enabling the application of dipolar AC waveforms to opposing rods in three quadrupole arrays in the ion path. This modification allows for resonance excitation of ions to effect ion activation, selective ion isolation, and ion parking. The other set of opposing rods in each array is enabled for the application of dipolar DC voltages for the purpose of broad-band (non-selective) ion heating. The plates between each quadrupole array are enabled for the application of either DC or AC (or both) voltages. The use of AC voltages allows for the simultaneous storage of ions of opposite polarity, thereby enabling mutual storage ion/ion reactions. Ions derived from nano-electrospray ionization of GroEL and β-galactosidase under native conditions were used to evaluate limits of instrument performance, in terms of m/z range, ion isolation, and ion storage. After adjustment of the pulser frequency, ions as high in m/z as 400,000 were detected. Significant losses in efficiency were noted above m/z 250,000 that is likely due to roll-over in the ion detector efficiency and possibly also due to limitations in ion transfer efficiency from the collision quadrupole to the pulser region of the mass analyzer. No measurable decrease in the apparent mass resolving power was noted upon charge state reduction of the model ions. Resonance ejection techniques that employ the dipolar AC capabilities of the quadrupoles allow for ion isolation at m/z values much greater than the RF/DC limitation of Q1 of m/z = 2100. For example, at the highest low-mass cutoff achievable in the collision quadrupole (m/z = 500), it is possible to isolate ions of m/z as high as 62,000. This is limited by the lowest dipolar AC frequency (5 kHz) that can be applied. A simple model is included to provide for an estimate of the ion cloud radius based on ion m/z, ion z, and ion trap operating conditions. The model predicts that singly charged ions of 1 MDa and thermal energy can be contained in the ion trap at the maximum low-mass cutoff, although such an ion would not be detected efficiently. Doubly charged GroEL ions were observed experimentally. Collectively, the performance characteristics at high m/z, the functionality provided by the standard instrument capabilities, the modifications described above, and highly flexible instrument control software provide for a highly versatile platform for the study of high mass ion/ion reactions.
Collapse
Affiliation(s)
- Jay S. Bhanot
- Department of Chemistry, Purdue University, West Lafayette, IN, USA 47907-2084
| | | | | | - Hsi-Chun Chao
- Department of Chemistry, Purdue University, West Lafayette, IN, USA 47907-2084
| | - Nicolas J. Pizzala
- Department of Chemistry, Purdue University, West Lafayette, IN, USA 47907-2084
| | | | | | | | - Scott A. McLuckey
- Department of Chemistry, Purdue University, West Lafayette, IN, USA 47907-2084
| |
Collapse
|
12
|
Covey T. Where have all the ions gone, long time passing? Tandem quadrupole mass spectrometers with atmospheric pressure ionization sensitivity gains since the mid-1970s. A perspective. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2022:e9354. [PMID: 35830299 DOI: 10.1002/rcm.9354] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 05/09/2022] [Accepted: 07/07/2022] [Indexed: 06/15/2023]
Abstract
The gains in sensitivity since 1975 for quadrupole mass spectrometers equipped with atmospheric pressure ionization (API), and in particular triple quadrupole mass spectrometers (QqQs) since 1981, have been driven by the needs of the environmental, biomedical, agricultural, and other scientific research, industrial, regulatory, legal, and sporting communities to continually achieve lower limits of quantitation and identification. QqQs have realized a one-million-fold improvement in sensitivity attempting to address these needs over the past two score years. It is the purpose of this article to describe how that came about, not through an exhaustive review of the literature, but rather by describing what general approaches were used across the industry to improve sensitivity and provide some examples to illustrate its evolution. The majority of the gains came from the ion source and its interface to the vacuum system. "Sampling efficiency" is a measurement of the losses in this area so will be a focus of this review. The discovery of the phenomenon of collisional focusing was key to improving sampling efficiency because it enabled designs that increased the ion-containing gas loads from the ion source, using staged differential pumping backed by increasingly larger pumps, and prevented the scattering losses of ions in the resulting gas expansion inside vacuum. Likewise, systems with smaller pumps and lower ion-containing gas loads could be designed with size and cost reduction in mind while maintaining reasonable sampling efficiencies. As a consequence, advancements in the designs of both larger and smaller turbomolecular vacuum pumps were accelerated by pump manufacturers to accommodate the explosive growth in the use of API-QqQ and API-ion trap mass spectrometers that occurred in the 1990s and continued into the new millennium. Sampling efficiency was further improved by increasing the ion yield from electrospray by increasing the rate of droplet desolvation. An estimate of the practical limit to further sensitivity improvements beyond what has been achieved to date is provided to shed light on what to expect in the future. Lastly, the implications and unforeseen consequences of the sensitivity gains are considered with a particular focus on how they have enabled a dramatic increase in daily sample throughput on triple quadrupole and other types of mass spectrometers.
Collapse
|
13
|
Pursell ME, Sharif D, DeBastiani A, Li C, Majuta S, Li P, Valentine SJ. Development of cVSSI-APCI for the Improvement of Ion Suppression and Matrix Effects in Complex Mixtures. Anal Chem 2022; 94:9226-9233. [PMID: 35729103 PMCID: PMC9260805 DOI: 10.1021/acs.analchem.1c05136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The new ionization technique termed vibrating sharp-edge spray ionization (cVSSI) has been coupled with corona discharge to investigate atmospheric pressure chemical ionization (APCI) capabilities. The optimized source was evaluated for its ability to enhance ion signal intensity, overcome matrix effects, and limit ion suppression. The results have been compared with state-of-the-art ESI source performance as well as a new APCI-like source. In methanol, the ion signal intensity increased 10-fold and >10-fold for cocaine and the suppressed analytes, respectively. The ability to overcome ion suppression was improved from 2-fold to 16-fold for theophylline and vitamin D2, respectively. For aqueous samples, ion signal levels increased by two orders of magnitude for all analytes. In both solvent systems, the signal-to-noise ratios also increased for all suppressed analytes. One example of the characterization of low-ionizing (by ESI or cVSSI alone) species in the presence of high-ionizing species by direct analysis from a cotton swab is presented. The work is discussed with respect to the advantages of cVSSI-APCI for direct, in situ, and field analyses.
Collapse
Affiliation(s)
- Madison E. Pursell
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV 26506
| | - Daud Sharif
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV 26506
| | - Anthony DeBastiani
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV 26506
| | - Chong Li
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV 26506
| | - Sandra Majuta
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV 26506
| | - Peng Li
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV 26506
| | - Stephen J. Valentine
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV 26506
| |
Collapse
|
14
|
Porous layer open tubular nano liquid chromatography directly coupled to electron ionization mass spectrometry. J Chromatogr A 2022; 1674:463143. [PMID: 35588591 DOI: 10.1016/j.chroma.2022.463143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 04/29/2022] [Accepted: 05/11/2022] [Indexed: 11/20/2022]
Abstract
A 25 µm i.d x 1.2 m length PS-DVB porous layer open tubular column (PLOT) was prepared and assessed in the configuration of a nano liquid chromatography coupled to an electron ionization mass spectrometry system (OT-nanoLC-EI-Ms), via the direct insertion of the column outlet into the ionization source. The developed system's operational parameters were comprehensively studied, and the setup performance was investigated employing both unidimensional and column switching configurations. As a result, the OT-nanoLC-EI-MS system demonstrated competitive applicability in separating non-amenable ESI compounds, such as polyaromatic hydrocarbons (PAHs) and non-amenable GC compounds such as thermolabile pesticides. Furthermore, with excellent chromatographic performance, the PLOT columns can work under more compatible EI-detection conditions - such as the elution with 100% organic solvent. For example, PAHs retention factors ranged between 1.5 and 2.2 for 100% MeCN mobile phase, and more than 33,000 plates per meter for naphthalene at 50 nL/min flow rate. In analyzing thermolabile pesticides, the column switching PLOT-nanoLC-EI-MS system provided LODs of 25 µg/L, demonstrating suitable intra e interday reproducibility (% RSD < 13%, n = 3), and possibilities the direct injection of raw samples with suitable robustness.
Collapse
|
15
|
Ferré S, Boccard J, Rudaz S, González-Ruiz V. Evaluation of Prototype CE-MS Interfaces. Methods Mol Biol 2022; 2531:1-13. [PMID: 35941475 DOI: 10.1007/978-1-0716-2493-7_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Capillary electrophoresis-mass spectrometry (CE-MS) coupling is a powerful analytical solution bringing together the separation power of CE and the wealth of chemical information afforded by MS. Nevertheless, interfaces making the hyphenation of both techniques possible have always been the subject of a quest for improvement by their users in search for more sensitive and robust setups. This fact has led to numerous technical developments and new interface designs claiming to outrival existing approaches in different aspects. Nevertheless, the task of evaluating and comparing a new interface to previous solutions is not always straightforward. Issued from our own experience in the field, we herein propose a protocol to optimize the operation parameters of a new CE-MS interface design, assess its analytical performance, and compare it to a reference interface if desired. Electrospray stability, sensitivity, reproducibility, and robustness are practically evaluated as key elements of the process.
Collapse
Affiliation(s)
- Sabrina Ferré
- Institute of Pharmaceutical Sciences of Western Switzerland (ISPSO), University of Geneva, Geneva, Switzerland
- School of Pharmaceutical Sciences, University of Geneva, Geneva, Switzerland
| | - Julien Boccard
- Institute of Pharmaceutical Sciences of Western Switzerland (ISPSO), University of Geneva, Geneva, Switzerland
- School of Pharmaceutical Sciences, University of Geneva, Geneva, Switzerland
- Swiss Centre for Applied Human Toxicology, Basel, Switzerland
| | - Serge Rudaz
- Institute of Pharmaceutical Sciences of Western Switzerland (ISPSO), University of Geneva, Geneva, Switzerland
- School of Pharmaceutical Sciences, University of Geneva, Geneva, Switzerland
- Swiss Centre for Applied Human Toxicology, Basel, Switzerland
| | - Víctor González-Ruiz
- Institute of Pharmaceutical Sciences of Western Switzerland (ISPSO), University of Geneva, Geneva, Switzerland.
- School of Pharmaceutical Sciences, University of Geneva, Geneva, Switzerland.
- Swiss Centre for Applied Human Toxicology, Basel, Switzerland.
| |
Collapse
|
16
|
OUP accepted manuscript. J Appl Lab Med 2022; 7:945-970. [DOI: 10.1093/jalm/jfac010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 01/21/2022] [Indexed: 11/13/2022]
|
17
|
Huang DY, Wang MJ, Wu JJ, Chen YC. Ionization of Volatile Organics and Nonvolatile Biomolecules Directly from a Titanium Slab for Mass Spectrometric Analysis. Molecules 2021; 26:molecules26226760. [PMID: 34833852 PMCID: PMC8623480 DOI: 10.3390/molecules26226760] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/05/2021] [Accepted: 11/07/2021] [Indexed: 11/16/2022] Open
Abstract
Atmospheric pressure chemical ionization (APCI)-mass spectrometry (MS) and electrospray ionization (ESI)-MS can cover the analysis of analytes from low to high polarities. Thus, an ion source that possesses these two ionization functions is useful. Atmospheric surface-assisted ionization (ASAI), which can be used to ionize polar and nonpolar analytes in vapor, liquid, and solid forms, was demonstrated in this study. The ionization of analytes through APCI or ESI was induced from the surface of a metal substrate such as a titanium slab. ASAI is a contactless approach operated at atmospheric pressure. No electric contacts nor any voltages were required to be applied on the metal substrate during ionization. When placing samples with high vapor pressure in condensed phase underneath a titanium slab close to the inlet of the mass spectrometer, analytes can be readily ionized and detected by the mass spectrometer. Furthermore, a sample droplet (~2 μL) containing high-polarity analytes, including polar organics and biomolecules, was ionized using the titanium slab. One titanium slab is sufficient to induce the ionization of analytes occurring in front of a mass spectrometer applied with a high voltage. Moreover, this ionization method can be used to detect high volatile or polar analytes through APCI-like or ESI-like processes, respectively.
Collapse
Affiliation(s)
- De-Yi Huang
- Department of Applied Chemistry, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan;
- Department of Applied Chemistry, National Chiao Tung University, Hsinchu 300, Taiwan
| | - Meng-Jiy Wang
- Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan;
| | - Jih-Jen Wu
- Department of Chemical Engineering, National Cheng Kung University, Tainan 700, Taiwan;
| | - Yu-Chie Chen
- Department of Applied Chemistry, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan;
- Department of Applied Chemistry, National Chiao Tung University, Hsinchu 300, Taiwan
- Correspondence: ; Tel.: +886-3-5131527; Fax: +886-3-5723764
| |
Collapse
|
18
|
Javaheri H, Schneider BB. Ion Guide for Improved Atmosphere to Mass Spectrometer Vacuum Ion Transfer. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:1945-1951. [PMID: 33400869 DOI: 10.1021/jasms.0c00394] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Various approaches for transmitting ions from atmosphere to the deep vacuum required for mass analysis have been developed with the goal to increase the ion to gas ratio while maintaining high ion transmission efficiency. Since the vast majority of ion losses occurs in the atmospheric pressure ion source, an effective way to improve sampling of those ions is to increase the atmosphere to vacuum aperture diameter. However, as the aperture diameter is increased, the resulting intense free jet gas expansion and subsequent gas beam can scatter ions in the first vacuum region. The interface described here provides an optimized flow field to the second vacuum stage, with a unique geometry to counter the ion losses from scattering collisions with the gas. Two additional differentially pumped quadrupole ion guides are used to further improve the ion to gas ratio, resulting in an ion transfer efficiency improvement of 5-6× over a two-stage differentially pumped interface with quadrupole ion guides. The interface also demonstrates efficient declustering and fragmentation capabilities beneficial for reducing background chemical noise.
Collapse
Affiliation(s)
- Hassan Javaheri
- SCIEX, 71 Four Valley Drive, Concord, Ontario, Canada L4K 4V8
| | | |
Collapse
|
19
|
Markert C, Thinius M, Lehmann L, Heintz C, Stappert F, Wissdorf W, Kersten H, Benter T, Schneider BB, Covey TR. Observation of charged droplets from electrospray ionization (ESI) plumes in API mass spectrometers. Anal Bioanal Chem 2021; 413:5587-5600. [PMID: 34215914 PMCID: PMC8410725 DOI: 10.1007/s00216-021-03452-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 05/11/2021] [Accepted: 06/02/2021] [Indexed: 11/28/2022]
Abstract
Electrospray ionization (ESI) generates bare analyte ions from charged droplets, which result from spraying a liquid in a strong electric field. Experimental observations available in the literature suggest that at least a significant fraction of the initially generated droplets remain large, have long lifetimes, and can thus aspirate into the inlet system of an atmospheric pressure ionization mass spectrometer (API-MS). We report on the observation of fragment signatures from charged droplets penetrating deeply the vacuum stages of three commercial mass spectrometer systems with largely different ion source and spray configurations. Charged droplets can pass through the ion source and pressure reduction stages and even into the mass analyzer region. Since droplet signatures were found in all investigated instruments, the incorporation of charged droplets is considered a general phenomenon occurring with common spray conditions in ESI sources.
Collapse
Affiliation(s)
- Clara Markert
- Institute for Pure and Applied Mass Spectrometry, Physical and Theoretical Chemistry, University of Wuppertal, 42119, Wuppertal, Germany
| | - Marco Thinius
- Institute for Pure and Applied Mass Spectrometry, Physical and Theoretical Chemistry, University of Wuppertal, 42119, Wuppertal, Germany
| | - Laura Lehmann
- Institute for Pure and Applied Mass Spectrometry, Physical and Theoretical Chemistry, University of Wuppertal, 42119, Wuppertal, Germany
| | - Chris Heintz
- Institute for Pure and Applied Mass Spectrometry, Physical and Theoretical Chemistry, University of Wuppertal, 42119, Wuppertal, Germany
| | - Florian Stappert
- Institute for Pure and Applied Mass Spectrometry, Physical and Theoretical Chemistry, University of Wuppertal, 42119, Wuppertal, Germany
| | - Walter Wissdorf
- Institute for Pure and Applied Mass Spectrometry, Physical and Theoretical Chemistry, University of Wuppertal, 42119, Wuppertal, Germany.
| | - Hendrik Kersten
- Institute for Pure and Applied Mass Spectrometry, Physical and Theoretical Chemistry, University of Wuppertal, 42119, Wuppertal, Germany
| | - Thorsten Benter
- Institute for Pure and Applied Mass Spectrometry, Physical and Theoretical Chemistry, University of Wuppertal, 42119, Wuppertal, Germany
| | | | - Thomas R Covey
- SCIEX, 71 Four Valley Drive, Concord, ON, L4K 4V8, Canada
| |
Collapse
|
20
|
Schneider BB, Javaheri H, Bedford L, Covey TR. Sampling Efficiency Improvement to an Electrospray Ionization Mass Spectrometer and Its Implications for Liquid Chromatography Based Inlet Systems in the Nanoliter to Milliliter per Minute Flow Range. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:1441-1447. [PMID: 33979156 DOI: 10.1021/jasms.1c00053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
This paper describes electrospray sampling efficiency measurements obtained on a triple quadrupole mass spectrometer equipped with a large atmosphere to vacuum sampling aperture and modified ion optics designed to confine the ions traveling in the intense expanding gas beam and prevent scattering losses in the entrance optics of the mass analyzer. Sampling efficiency, defined as the ratio of the number of ions captured in the first vacuum stage of the entrance optics to the number of analyte molecules entering the ion source, is a measure of sensitivity that takes into account both ionization efficiency at atmospheric pressure, the efficiency of transporting the ions from atmosphere to vacuum, and the efficiency of confining them in the subsequent gas expansion before mass analysis. Sampling efficiency measurements were conducted under high-performance liquid chromatography sample introduction conditions using columns and flow rates spanning the nanoflow (300 nL/min), microflow (3-60 μL/min), and milliflow (100-500 μL/min) ranges. The results show a convergence in the sampling efficiencies across this range, narrowing the sensitivity gap between the nanoflow and higher flow rate ranges largely because nanoflow sampling efficiency has been shown to be close to 100% for more than a decade, leaving little room for improvement. Under situations where sample volumes are not limiting, lower concentration detection limits can now be achieved with the higher flow rate systems versus nanoflow as a direct consequence of the higher sample loading capacity of the columns and the reduction in the difference in their ion sampling efficiencies.
Collapse
Affiliation(s)
| | - Hassan Javaheri
- SCIEX, 71 Four Valley Drive, Concord, Ontario L4K 4 V8, Canada
| | - Leigh Bedford
- SCIEX, 71 Four Valley Drive, Concord, Ontario L4K 4 V8, Canada
| | - Thomas R Covey
- SCIEX, 71 Four Valley Drive, Concord, Ontario L4K 4 V8, Canada
| |
Collapse
|
21
|
Peng Z, Liu JX, Zhu H, Guo T, Xu L, Dong JG, Cheng P, Zhou Z. Development of a new atmospheric pressure plasmaspray ionization for ambient mass spectrometry. JOURNAL OF MASS SPECTROMETRY : JMS 2021; 56:e4629. [PMID: 32767454 DOI: 10.1002/jms.4629] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/29/2020] [Accepted: 07/20/2020] [Indexed: 06/11/2023]
Abstract
A new atmospheric pressure ionization method, plasmaspray ionization, termed as PSI, was developed to be an alternative ambient ion source for mass spectrometry. It comprises a plasma jet device and a sample spray part. While the nonthermal plasma jet strikes the surface of stainless steel tube out of the spray capillary, the sprayed sample will be ionized with the assistant of auxiliary gas. Although PSI is a little bit more complex than electrospray ionization (ESI) in instrument, it shows both better linearity and higher sensitivity for organic compounds. For protein samples, it presents wider distributions of multiply charged ions and higher mass resolution without sacrificing any sensitivity. For the mechanism of PSI, the charge build-up process on the tip of capillary should play a key role for the ion formation, and the stimulated pulsed voltage on the flow tube will promote the ion aggregation speed until the charge density is high enough. PSI source contains the features of plasma ionization and ESI and can be considered as a novel combo bridging these techniques. These results reflect that this method of PSI can be applied and further developed as a versatile new ion source for a wild range of organic and biological samples.
Collapse
Affiliation(s)
- Zhen Peng
- Institute of Mass Spectrometer and Atmospheric Environment, Jinan University, Guangzhou, China
| | - Ji-Xing Liu
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai, China
| | - Hui Zhu
- Kunshan Hexin Mass Spectrometry Technology Co., Ltd., Kunshan, China
| | - Teng Guo
- Institute of Mass Spectrometer and Atmospheric Environment, Jinan University, Guangzhou, China
| | - Li Xu
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai, China
| | - Jun-Guo Dong
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai, China
| | - Ping Cheng
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai, China
| | - Zhen Zhou
- Institute of Mass Spectrometer and Atmospheric Environment, Jinan University, Guangzhou, China
| |
Collapse
|
22
|
Martin LM, Konermann L. Sulfolane-Induced Supercharging of Electrosprayed Salt Clusters: An Experimental/Computational Perspective. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:486-496. [PMID: 33334096 DOI: 10.1021/jasms.0c00377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
It is well-known that supercharging agents (SCAs) such as sulfolane enhance the electrospray ionization (ESI) charge states of proteins, although the mechanistic origins of this effect remain contentious. Only very few studies have explored SCA effects on analytes other than proteins or peptides. This work examines how sulfolane affects electrosprayed NaI salt clusters. Such alkali metal halide clusters have played a key role for earlier ESI mechanistic studies, making them interesting targets for supercharging investigations. ESI of aqueous NaI solutions predominantly generated singly charged [NanI(n-1)]+ clusters. The addition of sulfolane resulted in abundant doubly charged [NanI(n-2)Sulfolanes]2+ species. These experimental data for the first time demonstrate that electrosprayed salt clusters can undergo supercharging. Molecular dynamics (MD) simulations of aqueous ESI nanodroplets containing Na+/I- with and without sulfolane were conducted to obtain atomistic insights into the supercharging mechanism. The simulations produced [NanIi]z+ and [NanIiSulfolanes]z+ clusters similar to those observed experimentally. The MD trajectories demonstrated that these clusters were released into the gas phase upon droplet evaporation to dryness, in line with the charged residue model. Sulfolane was found to evaporate much more slowly than water. This slow evaporation, in conjunction with the large dipole moment of sulfolane, resulted in electrostatic stabilization of the shrinking ESI droplets and the final clusters. Hence, charge-dipole stabilization causes the sulfolane-containing droplets and clusters to retain more charge, thereby providing the mechanistic foundation of salt cluster supercharging.
Collapse
Affiliation(s)
- Leanne M Martin
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| |
Collapse
|
23
|
Yin V, Konermann L. Probing the Effects of Heterogeneous Oxidative Modifications on the Stability of Cytochrome c in Solution and in the Gas Phase. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:73-83. [PMID: 32401029 DOI: 10.1021/jasms.0c00089] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Covalent modifications by reactive oxygen species can modulate the function and stability of proteins. Thermal unfolding experiments in solution are a standard tool for probing oxidation-induced stability changes. Complementary to such solution investigations, the stability of electrosprayed protein ions can be assessed in the gas phase by collision-induced unfolding (CIU) and ion-mobility spectrometry. A question that remains to be explored is whether oxidation-induced stability alterations in solution are mirrored by the CIU behavior of gaseous protein ions. Here, we address this question using chloramine-T-oxidized cytochrome c (CT-cyt c) as a model system. CT-cyt c comprises various proteoforms that have undergone MetO formation (+16 Da) and Lys carbonylation (LysCH2-NH2 → LysCHO, -1 Da). We found that CT-cyt c in solution was destabilized, with a ∼5 °C reduced melting temperature compared to unmodified controls. Surprisingly, CIU experiments revealed the opposite trend, i.e., a stabilization of CT-cyt c in the gas phase. To pinpoint the source of this effect, we performed proteoform-resolved CIU on CT-cyt c fractions that had been separated by cation exchange chromatography. In this way, it was possible to identify MetO formation at residue 80 as the key modification responsible for stabilization in the gas phase. Possibly, this effect is caused by newly formed contacts of the sulfoxide with aromatic residues in the protein core. Overall, our results demonstrate that oxidative modifications can affect protein stability in solution and in the gas phase very differently.
Collapse
Affiliation(s)
- Victor Yin
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| |
Collapse
|
24
|
Ahmed E, Xiao D, Kabir KMM, Fletcher J, Donald WA. Ambient Pressure Ion Funnel: Concepts, Simulations, and Analytical Performance. Anal Chem 2020; 92:15811-15817. [DOI: 10.1021/acs.analchem.0c02938] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ezaz Ahmed
- School of Chemistry, University of New South Wales, Sydney, NSW 2052 Australia
| | - Dan Xiao
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW 2052 Australia
| | - K. M. Mohibul Kabir
- School of Chemistry, University of New South Wales, Sydney, NSW 2052 Australia
| | - John Fletcher
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW 2052 Australia
| | - William A. Donald
- School of Chemistry, University of New South Wales, Sydney, NSW 2052 Australia
| |
Collapse
|
25
|
Saito-Shida S, Nagata M, Nemoto S, Akiyama H. Multi-residue determination of pesticides in green tea by gas chromatography-tandem mass spectrometry with atmospheric pressure chemical ionisation using nitrogen as the carrier gas. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2020; 38:125-135. [PMID: 33232630 DOI: 10.1080/19440049.2020.1846082] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Helium is commonly used as a carrier gas in gas chromatography-tandem mass spectrometry (GC-MS/MS); however, there are growing concerns regarding its global shortage and the resulting limited supply and high cost. Using nitrogen as an alternative carrier gas in GC-MS/MS with the widely used electron ionisation (EI) technique leads to a significantly lower sensitivity; thus, in this study, we explored the use of atmospheric-pressure chemical ionisation (APCI) as the ionisation method and examined the applicability of GC-(APCI)MS/MS with nitrogen gas for the determination of pesticide residues. GC-(APCI)MS/MS using nitrogen provided slightly wider peaks, and poorer isomeric separation compared to those using helium under identical conditions; however, the peak intensities were comparable. GC-(APCI)MS/MS using nitrogen was validated for 166 pesticides in green tea at a spiking level of 0.01 mg/kg and was compared with the conventional GC-(EI)MS/MS using helium gas. Except dimethomorph and resmethrin, GC-(APCI)MS/MS showed satisfactory results that were comparable to those of GC-(EI)MS/MS for most compounds, with trueness in the range of 73%-95% and relative standard deviations of <11%. The sensitivity and selectivity of GC-(APCI)MS/MS with nitrogen were superior to those of GC-(EI)MS/MS with helium. Therefore, GC-(APCI)MS/MS using nitrogen as the carrier gas, which has minimal concerns related to availability, could be a promising alternative to the conventional GC-(EI)MS/MS technique that employs helium.
Collapse
Affiliation(s)
| | - Mari Nagata
- Application Laboratory, Nihon Waters K.K., Waters Corporation , Tokyo, Japan
| | - Satoru Nemoto
- Division of Foods, National Institute of Health Sciences , Kanagawa, Japan
| | - Hiroshi Akiyama
- Division of Foods, National Institute of Health Sciences , Kanagawa, Japan
| |
Collapse
|
26
|
Bongaerts J, Segers K, Van Oudenhove L, Van Wanseele Y, Van Hulle M, De Bundel D, Mangelings D, Smolders I, Vander Heyden Y, Van Eeckhaut A. A comparative study of UniSpray and electrospray sources for the ionization of neuropeptides in liquid chromatography tandem mass spectrometry. J Chromatogr A 2020; 1628:461462. [PMID: 32822992 DOI: 10.1016/j.chroma.2020.461462] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 07/17/2020] [Accepted: 08/05/2020] [Indexed: 01/21/2023]
Abstract
Despite the extensive use of electrospray ionization (ESI) for the quantification of neuropeptides by liquid chromatography-tandem mass spectrometry (LC-MS/MS), poor ionization and transmission efficiency are described for this ionization interface. A new atmospheric pressure ionization source, named UniSpray, was recently developed and commercialized. In this study, the LC-MS performance of this new ionization interface is evaluated and compared with ESI for the quantification of seven neuropeptides. Besides comparison of signal intensities and charge state distributions, also signal-to-noise (S/N) ratios and accuracy and precision were assessed. Additionally, matrix effects of human precipitated plasma and rat microdialysate were evaluated as well as the effect of three supercharging agents on the ionization of the seven neuropeptides. UniSpray ionization resulted in signal intensities four to eight times higher at the optimal capillary/impactor voltage for all seven neuropeptides. S/N values at the other hand only increased by not more than a twofold when the UniSpray source was used. Moreover, UniSpray ionization resulted in a shift towards lower charge states for some neuropeptides. Evaluation of the matrix effects by a post-column infusion set-up resulted in different infusion profiles between ESI and UniSpray. The charge state distributions of the neuropeptides obtained with UniSpray are highly comparable with ESI. Finally, the effect of the supercharging agents on the ionization of the neuropeptides tends to be peptide-dependent with both ionization sources.
Collapse
Affiliation(s)
- Jana Bongaerts
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information (FASC), Center for Neurosciences (C4N), Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels, Belgium; Department of Analytical Chemistry, Applied Chemometrics and Molecular Modelling (FABI), Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels, Belgium.
| | - Karen Segers
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information (FASC), Center for Neurosciences (C4N), Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels, Belgium; Department of Analytical Chemistry, Applied Chemometrics and Molecular Modelling (FABI), Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels, Belgium.
| | | | - Yannick Van Wanseele
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information (FASC), Center for Neurosciences (C4N), Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels, Belgium.
| | | | - Dimitri De Bundel
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information (FASC), Center for Neurosciences (C4N), Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels, Belgium.
| | - Debby Mangelings
- Department of Analytical Chemistry, Applied Chemometrics and Molecular Modelling (FABI), Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels, Belgium.
| | - Ilse Smolders
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information (FASC), Center for Neurosciences (C4N), Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels, Belgium.
| | - Yvan Vander Heyden
- Department of Analytical Chemistry, Applied Chemometrics and Molecular Modelling (FABI), Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels, Belgium.
| | - Ann Van Eeckhaut
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information (FASC), Center for Neurosciences (C4N), Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels, Belgium.
| |
Collapse
|
27
|
Prabhu GRD, Ponnusamy VK, Witek HA, Urban PL. Sample Flow Rate Scan in Electrospray Ionization Mass Spectrometry Reveals Alterations in Protein Charge State Distribution. Anal Chem 2020; 92:13042-13049. [PMID: 32893617 DOI: 10.1021/acs.analchem.0c01945] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Sample flow rate is one of the parameters that influence the sensitivity of electrospray ionization (ESI) mass spectrometry. By varying the sample flow rate, initial droplets of different sizes can be generated. Protein molecules in small droplets may form gas-phase ions earlier than the ones in large droplets. Here, we have systematically studied the influence of sample flow rate on the ESI charge state distributions (CSDs) of model proteins. A dedicated programmable sample flow rate scanner was used to infuse protein samples at different flow rates into a mass spectrometer. The synergistic influence of sample flow rate and various electrolytes (ammonium acetate, ammonium bicarbonate, ammonium formate, and piperidine) was studied. Significant alterations to the CSDs with increasing flow rate were observed. For example, in the presence of ammonium acetate, at low flow rates, lower charge states of proteins showed high intensities, while at high flow rates, ions related to higher charge states of proteins dominated the spectra. On the other hand, in the presence of piperidine, a significant reduction in the ion currents of all charge states was observed during the flow rate scan. Our observations suggest that at low flow rates the protein molecules follow a charged residue model of ionization mechanism, and at high flow rates-due to structural changes in protein molecules in large ESI droplets-the charged residue and chain ejection models can possibly coexist. We propose the use of sample flow rate scan as a way to reveal the influence of flow rate on the CSDs of the studied proteins.
Collapse
Affiliation(s)
- Gurpur Rakesh D Prabhu
- Department of Applied Chemistry, National Chiao Tung University, 1001 University Road, Hsinchu 30010, Taiwan.,Department of Chemistry, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan
| | - Vinoth Kumar Ponnusamy
- Department of Medicinal and Applied Chemistry & Research Center for Environmental Medicine, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan.,Department of Medical Research, Kaohsiung Medical University Hospital, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan
| | - Henryk A Witek
- Department of Applied Chemistry, National Chiao Tung University, 1001 University Road, Hsinchu 30010, Taiwan.,Center for Emergent Functional Matter Science, National Chiao Tung University, 1001 University Road, Hsinchu 30010, Taiwan
| | - Pawel L Urban
- Department of Chemistry, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan.,Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan
| |
Collapse
|
28
|
Mass spectrometry-based metabolomics for an in-depth questioning of human health. Adv Clin Chem 2020; 99:147-191. [PMID: 32951636 DOI: 10.1016/bs.acc.2020.02.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Today, metabolomics is becoming an indispensable tool to get a more comprehensive analysis of complex living systems, providing insights on multiple aspects of physiology. Although its application in large scale population-based studies is very challenging due to the processing of large sample sets as well as the complexity of data information, its potential to characterize human health is well recognized. Technological advances in metabolomics pave the way for the efficient biomarker discovery of disease etiology, diagnosis and prognosis. Here, different steps of the metabolomics workflow, particularly mass spectrometry-based approaches, are discussed to demonstrate the potential of metabolomics to address biological questioning in human health. First an overview of metabolomics is provided with its interest in human health studies. Analytical development and advances in mass spectrometry instrumentation and computational tools are discussed regarding their application limits. Advancing metabolomics for applicability in human health and large-scale studies is presented and discussed in conclusion.
Collapse
|
29
|
Recent advances of ambient mass spectrometry imaging for biological tissues: A review. Anal Chim Acta 2020; 1117:74-88. [DOI: 10.1016/j.aca.2020.01.052] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 01/21/2020] [Accepted: 01/22/2020] [Indexed: 12/30/2022]
|
30
|
Strmeň T, Vrkoslav V, Bosáková Z, Cvačka J. Atmospheric pressure chemical ionization mass spectrometry at low flow rates: Importance of ion source housing. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2020; 34:e8722. [PMID: 31912928 DOI: 10.1002/rcm.8722] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 12/01/2019] [Accepted: 01/06/2020] [Indexed: 06/10/2023]
Abstract
RATIONALE Hyphenation of atmospheric pressure chemical ionization (APCI) mass spectrometry with capillary and micro high-performance liquid chromatography (HPLC) is attractive for many applications, but reliable ion sources dedicated to these conditions are still missing. There are a number of aspects to consider when designing such an ion source, including the susceptibility of the ionization processes to ambient conditions. Here we discuss the importance of ion source housing for APCI at low flow rates. METHODS Selected compounds dissolved in various solvents were used to study ionization reactions at 10 μL/min flow rate. APCI spectra were generated using the Ion Max-S source (Thermo Fisher Scientific) operated with or without the ion source housing. RESULTS The APCI spectra of most compounds measured in the open and enclosed ion sources were markedly different. The differences were explained by water and oxygen molecules that entered the plasma region of the open ion source. Water tended to suppress charge transfer processes while oxygen diminished electron capture reactions and prevented the formation of acetonitrile-related radical cations useful for localizing double bonds in lipids. The effects associated with the ion source housing were significantly less important for compounds that are easy to protonate or deprotonate. CONCLUSIONS The use of ion source housing prevented alternative ionization channels leading to unwanted or unexpected ions. Compared with the conventional flow rate mode (1 mL/min), the effects of ambient air components were significantly higher at 10 μL/min, emphasizing the need for ion source housing in APCI sources dedicated to low flow rates.
Collapse
Affiliation(s)
- Timotej Strmeň
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, CZ-166 10, Prague 6, Czech Republic
- Department of Analytical Chemistry, Faculty of Science, Charles University in Prague, Hlavova 2030/8, CZ-128 43, Prague 2, Czech Republic
| | - Vladimír Vrkoslav
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, CZ-166 10, Prague 6, Czech Republic
| | - Zuzana Bosáková
- Department of Analytical Chemistry, Faculty of Science, Charles University in Prague, Hlavova 2030/8, CZ-128 43, Prague 2, Czech Republic
| | - Josef Cvačka
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, CZ-166 10, Prague 6, Czech Republic
- Department of Analytical Chemistry, Faculty of Science, Charles University in Prague, Hlavova 2030/8, CZ-128 43, Prague 2, Czech Republic
| |
Collapse
|
31
|
Perraud V, Li X, Smith JN, Finlayson-Pitts BJ. Novel ionization reagent for the measurement of gas-phase ammonia and amines using a stand-alone atmospheric pressure gas chromatography (APGC) source. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2020; 34:e8561. [PMID: 31429122 DOI: 10.1002/rcm.8561] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 08/14/2019] [Accepted: 08/14/2019] [Indexed: 06/10/2023]
Abstract
RATIONALE Contaminants present in ambient air or in sampling lines can interfere with the target analysis through overlapping peaks or causing a high background. This study presents a positive outcome from the unexpected presence of N-methyl-2-pyrrolidone, released from a PALL HEPA filter, in the analysis of atmospherically relevant gas-phase amines using chemical ionization mass spectrometry. METHODS Gas-phase measurements were performed using a triple quadrupole mass spectrometer equipped with a modified atmospheric pressure gas chromatography (APGC) source which allows sampling of the headspace above pure amine standards. Gas-phase N-methyl-2-pyrrolidone (NMP) emitted from a PALL HEPA filter located in the inlet stream served as the ionizing agent. RESULTS This study demonstrates that some alkylamines efficiently form a [NMP + amine+H]+ cluster with NMP upon chemical ionization at atmospheric pressure. The extent of cluster formation depends largely on the proton affinity of the amine compared with that of NMP. Aromatic amines (aniline, pyridine) and diamines (putrescine) were shown not to form cluster ions with NMP. CONCLUSIONS The use of NMP as an ionizing agent with stand-alone APGC provided high sensitivity for ammonia and the smaller amines. The main advantages, in addition to sensitivity, are direct sampling into the APGC source and avoiding uptake on sampling lines which can be a significant problem with ammonia and amines.
Collapse
Affiliation(s)
- Véronique Perraud
- Department of Chemistry, University of California, Irvine, CA, 92697, USA
| | - Xiaoxiao Li
- Department of Chemistry, University of California, Irvine, CA, 92697, USA
| | - James N Smith
- Department of Chemistry, University of California, Irvine, CA, 92697, USA
| | | |
Collapse
|
32
|
Thinius M, Polaczek C, Langner M, Bräkling S, Haack A, Kersten H, Benter T. Charge Retention/Charge Depletion in ESI-MS: Experimental Evidence. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2020; 31:773-784. [PMID: 32150403 DOI: 10.1021/jasms.9b00044] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The effects of liquid and gas phase additives (chemical modifiers) on the ion signal distribution for Substance P (SP), recorded with a nanoelectrospray setup, are evaluated. Depletion of the higher charge state of Substance P ([SP+3H]3+) is observed with polar protic gas phase modifiers. This is attributed to their ability to form larger hydrogen-bonded clusters, whose proton affinity increases with cluster size. These clusters are able to deprotonate the higher charge state. "Supercharging agents" (SCAs) as well as aprotic polar gas phase modifiers, which promote the retention of the higher charge state of Substance P, do not form such large clusters under the given conditions and are therefore not able to deprotonate Substance P. Both SCAs and aprotic modifiers form clusters with the higher charge state, leading to stabilization of the charge. Whereas supercharging agents have low vapor pressures and are therefore enriched in late-stage electrospray droplets, the gas phase modifiers are volatile organic solvents. Collision induced dissociation experiments revealed that the addition of a modifier significantly delays the droplet evaporation and ion release process. This indicates that the droplet takes up the gas phase modifier to a certain extent (accommodation). Depending on the modifier's properties either charge depletion or retention may eventually be promoted.
Collapse
Affiliation(s)
- Marco Thinius
- Department of Physical and Theoretical Chemistry, University of Wuppertal, Gauss Str. 20, 42119 Wuppertal, Germany
| | - Christine Polaczek
- Department of Physical and Theoretical Chemistry, University of Wuppertal, Gauss Str. 20, 42119 Wuppertal, Germany
| | - Markus Langner
- Department of Physical and Theoretical Chemistry, University of Wuppertal, Gauss Str. 20, 42119 Wuppertal, Germany
| | - Steffen Bräkling
- Department of Physical and Theoretical Chemistry, University of Wuppertal, Gauss Str. 20, 42119 Wuppertal, Germany
| | - Alexander Haack
- Department of Physical and Theoretical Chemistry, University of Wuppertal, Gauss Str. 20, 42119 Wuppertal, Germany
| | - Hendrik Kersten
- Department of Physical and Theoretical Chemistry, University of Wuppertal, Gauss Str. 20, 42119 Wuppertal, Germany
| | - Thorsten Benter
- Department of Physical and Theoretical Chemistry, University of Wuppertal, Gauss Str. 20, 42119 Wuppertal, Germany
| |
Collapse
|
33
|
Wang W, Bajic S, John B, Emerson DR. Numerical Simulation of Flow Field and Ion Transport for Different Ion Source Sampling Interfaces of a Mass Spectrometer. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2020; 31:840-855. [PMID: 32134651 DOI: 10.1021/jasms.9b00103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Understanding ion transport mechanisms in the flow expansion section of the first vacuum region of a mass spectrometer (MS) with an atmospheric pressure ionization source is essential for optimizing the MS sampling interface design. In this study, numerical simulations of three types of ions in two different MS interface designs have been carried out. In contrast to previously reported numerical studies, nonequilibrium gas dynamics due to rarefied gas effects has been considered in modeling the flow expansion and a realistic space charge effect has been considered in a continuous ion injection mode. Numerical simulations reveal that a flat plate interface has a higher peak buffer gas velocity but a narrower zone of silence compared to the conical interface. Shock wave structures are clearly captured, and the Knudsen number distribution is displayed. Simulation results show that in the axial direction the buffer gas effect is much stronger than the electric force effect in the current configuration. The conical interface leads to both a strong ion acceleration in the zone of silence and a strong ion deceleration downstream. In the radial direction, both the electric force and buffer gas drag force play an important role. The conical interface introduces a relatively stronger ion focusing effect from the radial buffer gas effect and a stronger ion dispersion from the radial electric force than the flat plate interface. The net effect for the current configuration is an increase in ion losses for the conical interface. Nanoelectrospray ionization experiments were carried out to validate the ion transmission efficiency.
Collapse
Affiliation(s)
- Wei Wang
- STFC, Daresbury Laboratory, Warrington, Cheshire WA4 4AD, U.K
- Waters Corporation, Altrincham Rd, Wilmslow, Cheshire SK9 4AX, U.K
| | - Steve Bajic
- Waters Corporation, Altrincham Rd, Wilmslow, Cheshire SK9 4AX, U.K
| | - Benzi John
- STFC, Daresbury Laboratory, Warrington, Cheshire WA4 4AD, U.K
| | - David R Emerson
- STFC, Daresbury Laboratory, Warrington, Cheshire WA4 4AD, U.K
| |
Collapse
|
34
|
Zhang Q, Tian Y, Aliang M, Yu Q, Wang X. Implementation and study of dopant-assisted photoionization with a miniature capillary inlet ion trap mass spectrometer. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2020; 34:e8621. [PMID: 31658505 DOI: 10.1002/rcm.8621] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 09/26/2019] [Accepted: 10/01/2019] [Indexed: 06/10/2023]
Abstract
RATIONALE Dopant-assisted photoionization (PI) has been widely used in the mass spectrometric analysis of volatile compounds. Exploring simple doping methods will benefit parameter optimization and promote the application of this technique. METHODS A previously built miniature ion trap mass spectrometer was used to study dopant-assisted vacuum PI. The sampling system of this device was modified to provide three inlets for the simultaneous introduction of analytes, dopants, and auxiliary air. Then, dopant solution was directly injected into the ion trap chamber through a self-aspirating capillary inlet and rapidly evaporated without heating. Various dopant solutions were prepared and switched during the experiments. RESULTS When analyzing some aniline compounds, the signals of all analytes were improved by more than 10 times after the injection of 2% anisole solution as a dopant. In addition, anisole can provide analyte signals more than three times stronger than those provided by the other dopants. On the basis of the ionization energy selectivity of dopant-assisted PI, some isomers in the mass spectrometric analysis were distinguished using different additives. CONCLUSIONS In general, liquid doping is as feasible and as effective as other traditional methods, and using appropriate dopants with high PI efficiency or feeding more dopants contributes to the ionization of analytes. The proposed method also offers several unique merits, such as simple operation, low consumption, and smooth switching with minimal residue.
Collapse
Affiliation(s)
- Qian Zhang
- Division of Advanced Manufacturing, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, 100084, China
| | - Yuan Tian
- Division of Advanced Manufacturing, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China
| | - Mushage Aliang
- Division of Advanced Manufacturing, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China
| | - Quan Yu
- Division of Advanced Manufacturing, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China
| | - Xiaohao Wang
- Division of Advanced Manufacturing, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, 100084, China
| |
Collapse
|
35
|
Miniaturized liquid chromatography focusing on analytical columns and mass spectrometry: A review. Anal Chim Acta 2020; 1103:11-31. [DOI: 10.1016/j.aca.2019.12.064] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 12/19/2019] [Accepted: 12/20/2019] [Indexed: 12/17/2022]
|
36
|
Martin LM, Konermann L. Enhancing Protein Electrospray Charge States by Multivalent Metal Ions: Mechanistic Insights from MD Simulations and Mass Spectrometry Experiments. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2020; 31:25-33. [PMID: 32881517 DOI: 10.1021/jasms.9b00027] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The structure and reactivity of electrosprayed protein ions is governed by their net charge. Native proteins in non-denaturing aqueous solutions produce low charge states. More highly charged ions are formed when electrospraying proteins that are unfolded and/or exposed to organic supercharging agents. Numerous studies have explored the electrospray process under these various conditions. One phenomenon that has received surprisingly little attention is the charge enhancement caused by multivalent metal ions such as La3+ when electrospraying proteins out of non-denaturing solutions. Here, we conducted mass spectrometry and ion mobility spectrometry experiments, in combination with molecular dynamics (MD) simulations, to uncover the mechanistic basis of this charge enhancement. MD simulations of aqueous ESI droplets reproduced the experimental observation that La3+ boosts protein charge states relative to monovalent metals (e.g., Na+). The simulations showed that gaseous proteins were released by solvent evaporation to dryness, consistent with the charged residue model. Metal ion ejection kept the shrinking droplets close to the Rayleigh limit until ∼99% of the solvent had left. For droplets charged with Na+, metal adduction during the final stage of solvent evaporation produced low protein charge states. Droplets containing La3+ showed a very different behavior. The trivalent nature of La3+ favored adduction to the protein at a very early stage, when most of the solvent had not evaporated yet. This irreversible binding via multidentate contacts suppressed La3+ ejection from the vanishing droplets, such that the resulting gaseous proteins carried significantly more charge. Our results illustrate that MD simulations are suitable for uncovering intricate aspects of electrospray mechanisms, paving the way toward an atomistic understanding of mass spectrometry based analytical workflows.
Collapse
Affiliation(s)
- Leanne M Martin
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| |
Collapse
|
37
|
Mejía-Carmona K, Soares da Silva Burato J, Borsatto JVB, de Toffoli AL, Lanças FM. Miniaturization of liquid chromatography coupled to mass spectrometry. Trends Analyt Chem 2020. [DOI: 10.1016/j.trac.2019.115735] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
38
|
Duez Q, Metwally H, Hoyas S, Lemaur V, Cornil J, De Winter J, Konermann L, Gerbaux P. Effects of electrospray mechanisms and structural relaxation on polylactide ion conformations in the gas phase: insights from ion mobility spectrometry and molecular dynamics simulations. Phys Chem Chem Phys 2020; 22:4193-4204. [DOI: 10.1039/c9cp06391a] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Gas-phase polymer ions may retain structural features associated with their electrospray formation mechanisms.
Collapse
Affiliation(s)
- Quentin Duez
- Organic Synthesis and Mass Spectrometry Laboratory
- Center of Innovation and Research in Materials and Polymers (CIRMAP) – University of Mons (UMONS)
- B-7000 Mons
- Belgium
- Laboratory for Chemistry of Novel Materials
| | - Haidy Metwally
- Department of Chemistry
- The University of Western Ontario
- London
- Canada
| | - Sébastien Hoyas
- Organic Synthesis and Mass Spectrometry Laboratory
- Center of Innovation and Research in Materials and Polymers (CIRMAP) – University of Mons (UMONS)
- B-7000 Mons
- Belgium
- Laboratory for Chemistry of Novel Materials
| | - Vincent Lemaur
- Laboratory for Chemistry of Novel Materials
- Center of Innovation and Research in Materials and Polymers (CIRMAP) – University of Mons (UMONS)
- B-7000 Mons
- Belgium
| | - Jérôme Cornil
- Laboratory for Chemistry of Novel Materials
- Center of Innovation and Research in Materials and Polymers (CIRMAP) – University of Mons (UMONS)
- B-7000 Mons
- Belgium
| | - Julien De Winter
- Organic Synthesis and Mass Spectrometry Laboratory
- Center of Innovation and Research in Materials and Polymers (CIRMAP) – University of Mons (UMONS)
- B-7000 Mons
- Belgium
| | - Lars Konermann
- Department of Chemistry
- The University of Western Ontario
- London
- Canada
| | - Pascal Gerbaux
- Organic Synthesis and Mass Spectrometry Laboratory
- Center of Innovation and Research in Materials and Polymers (CIRMAP) – University of Mons (UMONS)
- B-7000 Mons
- Belgium
| |
Collapse
|
39
|
Quantitation of Cyclosporin A in Cell Culture Media by Differential Mobility Mass Spectrometry (DMS-MS/MS). Methods Mol Biol 2019. [PMID: 31729659 DOI: 10.1007/978-1-0716-0030-6_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Cell permeability is an important factor in determining the bioavailability of therapeutics that is usually measured by cell culture testing. The concentration of pharmaceutical in a medium such as Hank's Balanced Salt Solution with HEPES organic buffer (HBSS-HEPES) is measured at a series of time points, making simplicity and high throughput of the analytical method important characteristics. We report an electrospray differential mobility spectrometry mass spectrometry method (nanoESI-DMS-MS) for the rapid determination of cyclosporin A (CsA, cyclosporine) concentration in such a buffer. DMS technology provides gas phase atmospheric pressure ion filtration for small-molecule bioanalytical methods that suppresses interfering ions and reduces chemical noise, without the use of chromatography. This allows simplified sample preparation, fast calibration curve development, and shortened analysis times. It has also been noted that the DMS prefilter can reduce contamination of the mass spectrometer by salts, thereby extending mass spectrometer system uptime.In the application described here, DMS-MS/MS is applied to cyclosporine A (CsA) in cell medium. Sample preparation is limited to dilution with an ammonium acetate-methanol-water mobile phase and the addition of CsA-d4 internal standard. The isotope ratio data are obtained in DMS-MS MRM mode observing NH3 loss from the ammonium adduct of the two species. A calibration curve with high linearity (R2 = 0.998) is rapidly obtained with nearly zero intercept, while it was found that a liquid chromatography LC-MS method required a preliminary SPE step to obtain a linear calibration curve. The time for data acquisition in the DMS-MS MRM method with flow injection (FIA) or infusion introduction at ESI flow of 400 nL/min is typically 30 s leading to a cycle time of less than 1 min.
Collapse
|
40
|
Mullen M, Giordano BC. Combined secondary electrospray and corona discharge ionization (SECDI) for improved detection of explosive vapors using drift tube ion mobility spectrometry. Talanta 2019; 209:120544. [PMID: 31892090 DOI: 10.1016/j.talanta.2019.120544] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 11/06/2019] [Accepted: 11/07/2019] [Indexed: 12/26/2022]
Abstract
Secondary electrospray corona discharge ionization (SECDI) combines the principles of secondary electrospray ionization (SESI) and corona discharge (CD) to achieve higher sensitivity, which is demonstrated through the detection of 2,4,6-trinitrotoluene (TNT) and 2,6-dinitrotoluene (2,6-DNT) vapors using ion mobility spectrometry (IMS). Using SECDI, enhancements in the IMS signal for TNT and 2,6-DNT vapors at trace concentrations are as much as 2-26 times that observed with CD or SESI alone. The enhancement in sensitivity is hypothesized to result from an increase in ionization efficiency driven by a higher number of reactant ions associated with SECDI compared to either technique individually. The ability of SECDI to achieve higher sensitivity without the aid of dopant molecules demonstrates its merit as an alternative ionization technique.
Collapse
Affiliation(s)
- Matthew Mullen
- NRC Post-Doctoral Fellow, US Naval Research Laboratory, 4555 Overlook Ave SW, Washington, D.C., 20375, USA
| | - Braden C Giordano
- Chemistry Division, US Naval Research Laboratory, 4555 Overlook Ave SW, Washington, D.C., 20375, USA.
| |
Collapse
|
41
|
Kang Y, Schneider BB, Bedford L, Covey TR. Design Characteristics to Eliminate the Need for Parameter Optimization in Nanoflow ESI-MS. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:2347-2357. [PMID: 31418126 DOI: 10.1007/s13361-019-02301-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 07/23/2019] [Accepted: 07/23/2019] [Indexed: 06/10/2023]
Abstract
The sampling efficiency in electrospray ionization-mass spectrometry (ESI-MS) can be improved by decreasing the liquid flow rate to the nanoflow regime, where it is possible to draw a large fraction of the ESI plume into the mass spectrometer. This mode of operation is typically more difficult than ESI-MS at higher flow rates because it requires careful optimization of a number of parameters to achieve optimal sampling efficiency. In this work, we screened the relative impact on signal intensity and spray stability of factors that included sprayer position, spray electrode protrusion, sprayer tip shape, spray angle relative to the MS inlet, nebulizer gas flow rate, ESI potential, and means for generating the electric field to initiate electrospray. Based on the screening results, we explore the possibility of providing fixed optimal values for many of the key source parameters to eliminate much of the tuning that is required for conventional nanoflow sources. This approach has potential to greatly simplify nanoflow ESI-MS, while providing optimized sensitivity, stability, and robustness, with decreased variability between analyses.
Collapse
Affiliation(s)
- Yang Kang
- SCIEX, 71 Four Valley Drive, Concord, Ontario, L4K 4V8, Canada.
| | | | - Leigh Bedford
- SCIEX, 71 Four Valley Drive, Concord, Ontario, L4K 4V8, Canada
| | - Thomas R Covey
- SCIEX, 71 Four Valley Drive, Concord, Ontario, L4K 4V8, Canada
| |
Collapse
|
42
|
Ferré S, González-Ruiz V, Guillarme D, Rudaz S. Analytical strategies for the determination of amino acids: Past, present and future trends. J Chromatogr B Analyt Technol Biomed Life Sci 2019; 1132:121819. [PMID: 31704619 DOI: 10.1016/j.jchromb.2019.121819] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 09/25/2019] [Accepted: 09/27/2019] [Indexed: 12/27/2022]
Abstract
This review describes the analytical methods that have been developed over the years to tackle the high polarity and non-chromophoric nature of amino acids (AAs). First, the historical methods are briefly presented, with a strong focus on the use of derivatization reagents to make AAs detectable with spectroscopic techniques (ultraviolet and fluorescence) and/or sufficiently retained in reversed phase liquid chromatography. Then, an overview of the current analytical strategies for achiral separation of AAs is provided, in which mass spectrometry (MS) becomes the most widely used detection mode in combination with innovative liquid chromatography or capillary electrophoresis conditions to detect AAs at very low concentration in complex matrixes. Finally, some future trends of AA analysis are provided in the last section of the review, including the use of supercritical fluid chromatography (SFC), multidimensional liquid chromatography and electrophoretic separations, hyphenation of ion exchange chromatography to mass spectrometry, and use of ion mobility spectrometry mass spectrometry (IM-MS). Various application examples will also be presented throughout the review to highlight the benefits and limitations of these different analytical approaches for AAs determination.
Collapse
Affiliation(s)
- Sabrina Ferré
- Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, CMU - Rue Michel Servet 1, 1211 Geneva 4, Switzerland
| | - Víctor González-Ruiz
- Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, CMU - Rue Michel Servet 1, 1211 Geneva 4, Switzerland; Swiss Centre for Applied Human Toxicology (SCAHT), Switzerland
| | - Davy Guillarme
- Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, CMU - Rue Michel Servet 1, 1211 Geneva 4, Switzerland.
| | - Serge Rudaz
- Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, CMU - Rue Michel Servet 1, 1211 Geneva 4, Switzerland; Swiss Centre for Applied Human Toxicology (SCAHT), Switzerland
| |
Collapse
|
43
|
Zhang F, Hong J, Xu W, Qu F. Straight nano-electrospray ionization and its coupling of mobility capillary electrophoresis to mass spectrometry. Talanta 2019; 206:120183. [PMID: 31514879 DOI: 10.1016/j.talanta.2019.120183] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 07/24/2019] [Accepted: 07/26/2019] [Indexed: 12/18/2022]
Abstract
Mobility capillary electrophoresis (MCE) was developed previously in our group, which has the capabilities of ion separation and biomolecule hydrodynamic radius analysis. The coupling of MCE with mass spectrometry (MS) would greatly improve complex sample identification capability as well as system detection sensitivity. In the present study, a simple and robust ionization source, named as straight nano-electrospray ionization (nanoESI) source was developed, which was applied to couple MCE with MS. A stainless-steel needle attached directly at the end of an MCE capillary was used as the nanoESI emitter, and the connection between this emitter to the liquid flow in the MCE separation channel was established through a liquid bridge. After optimization, this straight nanoESI source enhanced the ion signal intensity by ~10 times when compared with a commercial nanoESI source. The MCE-straight nanoESI-MS system was also characterized in terms of mixture separation and peptide hydrodynamic radius measurements. Compared to our previous work when a UV detector was used in a commercial Lumex CE system (model Capel 105 M, St. Petersburg, Russia), peptides with much lower concentrations could be analyzed (from ~1 mg/mL to ~20 μg/mL) in terms of radius measurement.
Collapse
Affiliation(s)
- Fei Zhang
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Jie Hong
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Wei Xu
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China.
| | - Feng Qu
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China.
| |
Collapse
|
44
|
Wißdorf W, Lorenz M, Brockmann K, Benter T. Systematic Ion Source Parameter Assessment by Automated Determination of the Distribution of Ion Acceptance (DIA) Using APLI. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:1262-1275. [PMID: 31069698 DOI: 10.1007/s13361-019-02190-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 02/20/2019] [Accepted: 02/25/2019] [Indexed: 06/09/2023]
Abstract
The determination of the spatially resolved ion signal with atmospheric pressure laser ionization (APLI), which was introduced as distribution of ion acceptance (DIA), serves as a valuable tool for the understanding of complex and highly dynamical conditions in modern atmospheric pressure (AP) ion sources. DIA provides information about fluid dynamics, ion transport, and ion transformation processes in such sources and is an ideal basis for the validation of numerical models of the dynamics in the ion source enclosure.We present a fully automated setup for DIA measurements, which enabled us to acquire a comprehensive dataset of over 700 individual DIA measurements in a commercial AP ion source (Bruker Multi Purpose Ion Source, MPIS). Ion source parameters as voltages, gas heater temperatures and gas flows, were varied, and the effect of those parameters on the DIA of a chemically inert analyte, pyrene, was systematically investigated. It is shown that the response of the DIA is nonlinear and that gas dynamics largely dominates the ion transport in the ion source. Particularly, the position of the heated nebulizer, which is used to introduce one of two gas flows and the analyte into the ion source chamber, had a profound effect on the DIA. This suggests that the gas dynamics in the source switches between different states. The now available comprehensive DIA dataset reveals such critical effects and will guide further numerical modeling efforts to understand the details of the dynamics of ions in the source chamber. Graphical Abstract.
Collapse
Affiliation(s)
- Walter Wißdorf
- Department of Physical and Theoretical Chemistry, University of Wuppertal, Gauss Str. 20, 42119, Wuppertal, Germany.
| | - Matthias Lorenz
- Department of Physical and Theoretical Chemistry, University of Wuppertal, Gauss Str. 20, 42119, Wuppertal, Germany
- Oak Ridge National Laboratory, Center for Nanophase Materials Sciences, 1 Bethel Valley Rd, Oak Ridge, TN, 37831-6493, USA
| | - Klaus Brockmann
- Department of Physical and Theoretical Chemistry, University of Wuppertal, Gauss Str. 20, 42119, Wuppertal, Germany
| | - Thorsten Benter
- Department of Physical and Theoretical Chemistry, University of Wuppertal, Gauss Str. 20, 42119, Wuppertal, Germany
| |
Collapse
|
45
|
Cuyckens F. Mass spectrometry in drug metabolism and pharmacokinetics: Current trends and future perspectives. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2019; 33 Suppl 3:90-95. [PMID: 30019507 DOI: 10.1002/rcm.8235] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 07/06/2018] [Accepted: 07/08/2018] [Indexed: 06/08/2023]
Abstract
Drug Metabolism and Pharmacokinetics (DMPK) is a core scientific discipline within drug discovery and development as well as post-marketing. It helps to design and select the most promising drug candidate and obtain advanced insights on the processes that control absorption, distribution, metabolism and excretion (ADME) of the final drug candidate. Mass spectrometry is one of the key technologies applied in DMPK. Therefore, the continuous advances made in the field of mass spectrometry also directly impact the way in which we investigate the ADME properties of a compound, providing us with new tools to gather more information or improve our efficiency. An overview will be given of some important current trends and future perspectives in the field.
Collapse
Affiliation(s)
- Filip Cuyckens
- Janssen Research & Development, Turnhoutseweg 30, B-2340, Beerse, Belgium
| |
Collapse
|
46
|
Cutillas V, Murcia-Morales M, Gómez-Ramos MDM, Taha SM, Fernández-Alba AR. Supercritical fluid chromatography coupled to tandem mass spectrometry for the analysis of pesticide residues in dried spices. Benefits and drawbacks. Anal Chim Acta 2019; 1059:124-135. [DOI: 10.1016/j.aca.2019.01.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 12/05/2018] [Accepted: 01/07/2019] [Indexed: 12/13/2022]
|
47
|
Peters I, Metwally H, Konermann L. Mechanism of Electrospray Supercharging for Unfolded Proteins: Solvent-Mediated Stabilization of Protonated Sites During Chain Ejection. Anal Chem 2019; 91:6943-6952. [DOI: 10.1021/acs.analchem.9b01470] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Insa Peters
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Haidy Metwally
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| |
Collapse
|
48
|
Laaniste A, Leito I, Kruve A. ESI outcompetes other ion sources in LC/MS trace analysis. Anal Bioanal Chem 2019; 411:3533-3542. [PMID: 31025182 DOI: 10.1007/s00216-019-01832-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 03/14/2019] [Accepted: 04/04/2019] [Indexed: 11/26/2022]
Abstract
Choosing an appropriate ion source is a crucial step in liquid chromatography mass spectrometry (LC/MS) method development. In this paper, we compare four ion sources for LC/MS analysis of 40 pesticides in tomato and garlic matrices. We compare electrospray ionisation (ESI) source, thermally focused/heated electrospray (HESI), atmospheric pressure photoionisation (APPI) source with and without dopant, and multimode source in ESI mode, atmospheric pressure chemical ionisation (APCI) mode, and combined mode using both ESI and APCI, i.e. altogether seven different ionisation modes. The lowest limits of detection (LoDs) were obtained by ESI and HESI. Widest linear ranges were observed with the conventional ESI source without heated nebuliser gas. In comparison to HESI, ESI source was significantly less affected by matrix effect. APPI ranked second (after ESI) by not being influenced by matrix effect; therefore, it would be a good alternative to ESI if low LoDs are not required. Graphical abstract.
Collapse
Affiliation(s)
- Asko Laaniste
- Institute of Chemistry, University of Tartu, Ravila 14a, 50411, Tartu, Estonia.
| | - Ivo Leito
- Institute of Chemistry, University of Tartu, Ravila 14a, 50411, Tartu, Estonia
| | - Anneli Kruve
- Institute of Chemistry, University of Tartu, Ravila 14a, 50411, Tartu, Estonia
| |
Collapse
|
49
|
Hayasaka Y. Quantitative analysis of mousy off-flavour compound 2-acetyl tetrahydropyridine in wine using liquid chromatography tandem mass spectrometry interfaced with atmospheric chemical ionisation. J Chromatogr A 2019; 1588:108-114. [PMID: 30600164 DOI: 10.1016/j.chroma.2018.12.047] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 12/18/2018] [Accepted: 12/20/2018] [Indexed: 10/27/2022]
Abstract
2-Acetyltetrahydropyridine (ACTPY), tautomers of 2-acetyl-1,4,5,6-tetrahydropyridine and 2-acetyl-3,4,5,6-tetrahydropyridine, is reported as one of the major compounds responsible for mousy off-flavour wine. A simple and rapid method for the quantitation of ACTPY in wine using HPLC-APCI-MS/MS was developed. Only filtration and basification were required for sample preparation prior to analysis. The analytical run time was approximately 17 min for one sample. Precision and accuracy tests confirmed that the method was highly reliable and robust. Limits of quantitation (LOQ) for red and white wines were estimated to be 0.23 μg L-1, which was sufficiently sensitive to allow the quantitation of ACTPY at its odour threshold level in water. The method can be implemented for routine objective screening of wines for mousy off-flavour, to determine sensory threshold levels in wine and to aid further research aiming to reduce the occurrence of this fault in wine.
Collapse
Affiliation(s)
- Y Hayasaka
- The Australian Wine Research Institute, P. O. Box 197, Glen Osmond, South Australia 5064, Australia.
| |
Collapse
|
50
|
Konermann L, Metwally H, Duez Q, Peters I. Charging and supercharging of proteins for mass spectrometry: recent insights into the mechanisms of electrospray ionization. Analyst 2019; 144:6157-6171. [DOI: 10.1039/c9an01201j] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Molecular dynamics simulations have uncovered mechanistic details of the protein ESI process under various experimental conditions.
Collapse
Affiliation(s)
- Lars Konermann
- Department of Chemistry
- The University of Western Ontario
- London
- Canada
| | - Haidy Metwally
- Department of Chemistry
- The University of Western Ontario
- London
- Canada
| | - Quentin Duez
- Department of Chemistry
- The University of Western Ontario
- London
- Canada
| | - Insa Peters
- Department of Chemistry
- The University of Western Ontario
- London
- Canada
| |
Collapse
|