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Trimpin S, Yenchick FS, Lee C, Hoang K, Pophristic M, Karki S, Marshall DD, Lu IC, Lutomski CA, El-Baba TJ, Wang B, Pagnotti VS, Meher AK, Chakrabarty S, Imperial LF, Madarshahian S, Richards AL, Lietz CB, Moreno-Pedraza A, Leach SM, Gibson SC, Elia EA, Thawoos SM, Woodall DW, Jarois DR, Davis ETJ, Liao G, Muthunayake NS, Redding MJ, Reynolds CA, Anthony TM, Vithanarachchi SM, DeMent P, Adewale AO, Yan L, Wager-Miller J, Ahn YH, Sanderson TH, Przyklenk K, Greenberg ML, Suits AG, Allen MJ, Narayan SB, Caruso JA, Stemmer PM, Nguyen HM, Weidner SM, Rackers KJ, Djuric A, Shulaev V, Hendrickson TL, Chow CS, Pflum MKH, Grayson SM, Lobodin VV, Guo Z, Ni CK, Walker JM, Mackie K, Inutan ED, McEwen CN. New Processes for Ionizing Nonvolatile Compounds in Mass Spectrometry: The Road of Discovery to Current State-of-the-Art. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024. [PMID: 39374043 DOI: 10.1021/jasms.3c00122] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/08/2024]
Abstract
This Perspective covers discovery and mechanistic aspects as well as initial applications of novel ionization processes for use in mass spectrometry that guided us in a series of subsequent discoveries, instrument developments, and commercialization. Vacuum matrix-assisted ionization on an intermediate pressure matrix-assisted laser desorption/ionization source without the use of a laser, high voltages, or any other added energy was simply unbelievable, at first. Individually and as a whole, the various discoveries and inventions started to paint, inter alia, an exciting new picture and outlook in mass spectrometry from which key developments grew that were at the time unimaginable, and continue to surprise us in its simplistic preeminence. We, and others, have demonstrated exceptional analytical utility. Our current research is focused on how best to understand, improve, and use these novel ionization processes through dedicated platforms and source developments. These ionization processes convert volatile and nonvolatile compounds from solid or liquid matrixes into gas-phase ions for analysis by mass spectrometry using, e.g., mass-selected fragmentation and ion mobility spectrometry to provide accurate, and sometimes improved, mass and drift time resolution. The combination of research and discoveries demonstrated multiple advantages of the new ionization processes and established the basis of the successes that lead to the Biemann Medal and this Perspective. How the new ionization processes relate to traditional ionization is also presented, as well as how these technologies can be utilized in tandem through instrument modification and implementation to increase coverage of complex materials through complementary strengths.
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Affiliation(s)
- Sarah Trimpin
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
- MSTM, LLC, Newark, Delaware 19711, United States
| | - Frank S Yenchick
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Chuping Lee
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Khoa Hoang
- MSTM, LLC, Newark, Delaware 19711, United States
- Saint Joseph's University, Philadelphia, Pennsylvania 19104, United States
| | - Milan Pophristic
- MSTM, LLC, Newark, Delaware 19711, United States
- Saint Joseph's University, Philadelphia, Pennsylvania 19104, United States
| | - Santosh Karki
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
- MSTM, LLC, Newark, Delaware 19711, United States
| | - Darrell D Marshall
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
- MSTM, LLC, Newark, Delaware 19711, United States
| | - I-Chung Lu
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
- Department of Chemistry, National Chung Hsing University, Taichung, 402, Taiwan
| | - Corinne A Lutomski
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Tarick J El-Baba
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Beixi Wang
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Vincent S Pagnotti
- Saint Joseph's University, Philadelphia, Pennsylvania 19104, United States
| | - Anil K Meher
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
- MSTM, LLC, Newark, Delaware 19711, United States
| | - Shubhashis Chakrabarty
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
- MSTM, LLC, Newark, Delaware 19711, United States
| | - Lorelei F Imperial
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Sara Madarshahian
- Saint Joseph's University, Philadelphia, Pennsylvania 19104, United States
| | - Alicia L Richards
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Christopher B Lietz
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | | | - Samantha M Leach
- Department of Forensic Sciences (DFS), Washington, D.C. 20024, United States
| | - Stephen C Gibson
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Efstathios A Elia
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Shameemah M Thawoos
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Daniel W Woodall
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Dean R Jarois
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Eric T J Davis
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Guochao Liao
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | | | - McKenna J Redding
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Christian A Reynolds
- Wayne State University School of Medicine, Detroit, Michigan 48201, United States
| | - Thilani M Anthony
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | | | - Paul DeMent
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Adeleye O Adewale
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Lu Yan
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - James Wager-Miller
- Gill Center for Biomolecular Science and Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana 47405, United States
| | - Young-Hoon Ahn
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Thomas H Sanderson
- Wayne State University School of Medicine, Detroit, Michigan 48201, United States
| | - Karin Przyklenk
- Wayne State University School of Medicine, Detroit, Michigan 48201, United States
| | - Miriam L Greenberg
- Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202, United States
| | - Arthur G Suits
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Matthew J Allen
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Srinivas B Narayan
- Detroit Medical Center: Detroit Hospital (DMC), Detroit, Michigan 48201, United States
| | - Joseph A Caruso
- Institute of Environmental Health Sciences, Wayne State University, Detroit Michigan 48202, United States
| | - Paul M Stemmer
- Institute of Environmental Health Sciences, Wayne State University, Detroit Michigan 48202, United States
| | - Hien M Nguyen
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Steffen M Weidner
- Federal Institute for Materials Research and Testing (BAM), Berlin 12489, Germany
| | - Kevin J Rackers
- Automation Techniques, Inc, Greensboro, North Carolina 27407, United States
| | - Ana Djuric
- College of Engineering, Wayne State University, Detroit, Michigan 48202, United States
| | - Vladimir Shulaev
- Department of Biological Sciences, BioDiscovery Institute, University of North Texas, Denton, Texas 76210, United States
| | - Tamara L Hendrickson
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Christine S Chow
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Mary Kay H Pflum
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Scott M Grayson
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | | | - Zhongwu Guo
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Chi-Kung Ni
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
| | - J Michael Walker
- Gill Center for Biomolecular Science and Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana 47405, United States
| | - Ken Mackie
- Gill Center for Biomolecular Science and Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana 47405, United States
| | - Ellen D Inutan
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
- MSTM, LLC, Newark, Delaware 19711, United States
- Mindanao State University Iligan Institute of Technology, Iligan City 9200, Philippines
| | - Charles N McEwen
- MSTM, LLC, Newark, Delaware 19711, United States
- Saint Joseph's University, Philadelphia, Pennsylvania 19104, United States
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2
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Zhai Z, Mavridou D, Damian M, Mutti FG, Schoenmakers PJ, Gargano AFG. Characterization of Complex Proteoform Mixtures by Online Nanoflow Ion-Exchange Chromatography-Native Mass Spectrometry. Anal Chem 2024; 96:8880-8885. [PMID: 38771719 PMCID: PMC11154664 DOI: 10.1021/acs.analchem.4c01760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 05/16/2024] [Accepted: 05/20/2024] [Indexed: 05/23/2024]
Abstract
The characterization of proteins and complexes in biological systems is essential to establish their critical properties and to understand their unique functions in a plethora of bioprocesses. However, it is highly difficult to analyze low levels of intact proteins in their native states (especially those exceeding 30 kDa) with liquid chromatography (LC)-mass spectrometry (MS). Herein, we describe for the first time the use of nanoflow ion-exchange chromatography directly coupled with native MS to resolve mixtures of intact proteins. Reference proteins and protein complexes with molecular weights between 10 and 150 kDa and a model cell lysate were separated using a salt-mediated pH gradient method with volatile additives. The method allowed for low detection limits (0.22 pmol of monoclonal antibodies), while proteins presented nondenatured MS (low number of charges and limited charge state distributions), and the oligomeric state of the complexes analyzed was mostly kept. Excellent chromatographic separations including the resolution of different proteoforms of large proteins (>140 kDa) and a peak capacity of 82 in a 30 min gradient were obtained. The proposed setup and workflows show great potential for analyzing diverse proteoforms in native top-down proteomics, opening unprecedented opportunities for clinical studies and other sample-limited applications.
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Affiliation(s)
- Ziran Zhai
- Analytical
Chemistry Group and Biocatalysis Group, Van’t Hoff Institute
for Molecular Sciences (HIMS), University
of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
- Centre
for Analytical Sciences Amsterdam, Van’t Hoff Institute for
Molecular Sciences (HIMS), University of
Amsterdam, Science Park
904, 1098 XH Amsterdam, The Netherlands
| | - Despoina Mavridou
- Analytical
Chemistry Group and Biocatalysis Group, Van’t Hoff Institute
for Molecular Sciences (HIMS), University
of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
- Centre
for Analytical Sciences Amsterdam, Van’t Hoff Institute for
Molecular Sciences (HIMS), University of
Amsterdam, Science Park
904, 1098 XH Amsterdam, The Netherlands
| | - Matteo Damian
- Analytical
Chemistry Group and Biocatalysis Group, Van’t Hoff Institute
for Molecular Sciences (HIMS), University
of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Francesco G. Mutti
- Analytical
Chemistry Group and Biocatalysis Group, Van’t Hoff Institute
for Molecular Sciences (HIMS), University
of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Peter J. Schoenmakers
- Analytical
Chemistry Group and Biocatalysis Group, Van’t Hoff Institute
for Molecular Sciences (HIMS), University
of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
- Centre
for Analytical Sciences Amsterdam, Van’t Hoff Institute for
Molecular Sciences (HIMS), University of
Amsterdam, Science Park
904, 1098 XH Amsterdam, The Netherlands
| | - Andrea F. G. Gargano
- Analytical
Chemistry Group and Biocatalysis Group, Van’t Hoff Institute
for Molecular Sciences (HIMS), University
of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
- Centre
for Analytical Sciences Amsterdam, Van’t Hoff Institute for
Molecular Sciences (HIMS), University of
Amsterdam, Science Park
904, 1098 XH Amsterdam, The Netherlands
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Trimpin S. A tutorial: Laserspray ionization and related laser-based ionization methods for use in mass spectrometry. MASS SPECTROMETRY REVIEWS 2023; 42:2234-2267. [PMID: 37462443 DOI: 10.1002/mas.21762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 09/30/2021] [Accepted: 11/15/2021] [Indexed: 08/09/2023]
Abstract
This Tutorial is to provide a summary of parameters useful for successful outcomes of laserspray ionization (LSI) and related methods that employ a laser to ablate a matrix:analyte sample to produce highly charged ions. In these methods the purpose of the laser is to transfer matrix-analyte clusters into the gas phase. Ions are hypothesized to be produced by a thermal process where emitted matrix:analyte gas-phase particles/clusters are charged and loss of matrix from the charged particles leads to release of the analyte ions into the gas phase. The thermal energy responsible for the charge-separation process is relatively low and not necessarily supplied by the laser; a heated inlet tube linking atmospheric pressure with the first vacuum stage of a mass spectrometer is sufficient. The inlet becomes the "ion source", and inter alia, pressure, temperature, and the matrix, which can be a solid, liquid, or combinations, become critical parameters. Injecting matrix:analyte into a heated inlet tube using laser ablation, a shockwave, or simply tapping, all produce the similar mass spectra. Applications are provided that showcase new opportunities in the field of mass spectrometry.
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Affiliation(s)
- Sarah Trimpin
- Department of Chemistry, Wayne State University, Detroit, Michigan, USA
- MSTM, LLC, Newark, Delaware, USA
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Majuta SN, DeBastiani A, Li P, Valentine SJ. Combining Field-Enabled Capillary Vibrating Sharp-Edge Spray Ionization with Microflow Liquid Chromatography and Mass Spectrometry to Enhance 'Omics Analyses. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:473-485. [PMID: 33417454 PMCID: PMC8132193 DOI: 10.1021/jasms.0c00376] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Field-enabled capillary vibrating sharp-edge spray ionization (cVSSI) has been combined with high-flow liquid chromatography (LC) and mass spectrometry (MS) to establish current ionization capabilities for metabolomics and proteomics investigations. Comparisons are made between experiments employing cVSSI and a heated electrospray ionization probe representing the state-of-the-art in microflow LC-MS methods for 'omics studies. For metabolomics standards, cVSSI is shown to provide an ionization enhancement by factors of 4 ± 2 for both negative and positive ion mode analyses. For chymotryptic peptides, cVSSI is shown to provide an ionization enhancement by factors of 5 ± 2 and 2 ± 1 for negative and positive ion mode analyses, respectively. Slightly broader high-performance liquid chromatography peaks are observed in the cVSSI datasets, and several studies suggest that this results from a slightly decreased post-split flow rate. This may result from partial obstruction of the pulled-tip emitter over time. Such a challenge can be remedied with the use of LC pumps that operate in the 10 to 100 μL·min-1 flow regime. At this early stage, the proof-of-principle studies already show ion signal advantages over state-of-the-art electrospray ionization (ESI) for a wide variety of analytes in both positive and negative ion mode. Overall, this represents a ∼20-50-fold improvement over the first demonstration of LC-MS analyses by voltage-free cVSSI. Separate comparisons of the ion abundances of compounds eluting under identical solvent conditions reveal ionization efficiency differences between cVSSI and ESI and may suggest varied contributions to ionization from different physicochemical properties of the compounds. Future investigations of parameters that could further increase ionization gains in negative and positive ion mode analyses with the use of cVSSI are briefly presented.
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Affiliation(s)
- Sandra N. Majuta
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown WV 26501
| | - Anthony DeBastiani
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown WV 26501
| | - Peng Li
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown WV 26501
| | - Stephen J. Valentine
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown WV 26501
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5
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Trimpin S, Marshall DD, Karki S, Madarshahian S, Hoang K, Meher AK, Pophristic M, Richards AL, Lietz CB, Fischer JL, Elia EA, Wang B, Pagnotti VS, Lutomski CA, El-Baba TJ, Lu IC, Wager-Miller J, Mackie K, McEwen CN, Inutan ED. An overview of biological applications and fundamentals of new inlet and vacuum ionization technologies. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2021; 35 Suppl 1:e8829. [PMID: 32402102 DOI: 10.1002/rcm.8829] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 05/01/2020] [Accepted: 05/10/2020] [Indexed: 06/11/2023]
Abstract
RATIONALE The developments of new ionization technologies based on processes previously unknown to mass spectrometry (MS) have gained significant momentum. Herein we address the importance of understanding these unique ionization processes, demonstrate the new capabilities currently unmet by other methods, and outline their considerable analytical potential. METHODS The inlet and vacuum ionization methods of solvent-assisted ionization (SAI), matrix-assisted ionization (MAI), and laserspray ionization can be used with commercial and dedicated ion sources producing ions from atmospheric or vacuum conditions for analyses of a variety of materials including drugs, lipids, and proteins introduced from well plates, pipet tips and plate surfaces with and without a laser using solid or solvent matrices. Mass spectrometers from various vendors are employed. RESULTS Results are presented highlighting strengths relative to ionization methods of electrospray ionization (ESI) and matrix-assisted laser desorption/ionization. We demonstrate the utility of multi-ionization platforms encompassing MAI, SAI, and ESI and enabling detection of what otherwise is missed, especially when directly analyzing mixtures. Unmatched robustness is achieved with dedicated vacuum MAI sources with mechanical introduction of the sample to the sub-atmospheric pressure (vacuum MAI). Simplicity and use of a wide array of matrices are attained using a conduit (inlet ionization), preferably heated, with sample introduction from atmospheric pressure. Tissue, whole blood, urine (including mouse, chicken, and human origin), bacteria strains and chemical on-probe reactions are analyzed directly and, especially in the case of vacuum ionization, without concern of carryover or instrument contamination. CONCLUSIONS Examples are provided highlighting the exceptional analytical capabilities associated with the novel ionization processes in MS that reduce operational complexity while increasing speed and robustness, achieving mass spectra with low background for improved sensitivity, suggesting the potential of this simple ionization technology to drive MS into areas currently underserved, such as clinical and medical applications.
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Affiliation(s)
- Sarah Trimpin
- Department of Chemistry, Wayne State University, Detroit, MI, 48202, USA
- MS™, LLC, Newark, DE, 19711, USA
| | - Darrell D Marshall
- Department of Chemistry, Wayne State University, Detroit, MI, 48202, USA
- MS™, LLC, Newark, DE, 19711, USA
| | - Santosh Karki
- Department of Chemistry, Wayne State University, Detroit, MI, 48202, USA
- MS™, LLC, Newark, DE, 19711, USA
| | | | - Khoa Hoang
- MS™, LLC, Newark, DE, 19711, USA
- University of the Sciences, Philadelphia, PA, 19104, USA
| | - Anil K Meher
- Department of Chemistry, Wayne State University, Detroit, MI, 48202, USA
- MS™, LLC, Newark, DE, 19711, USA
| | - Milan Pophristic
- MS™, LLC, Newark, DE, 19711, USA
- University of the Sciences, Philadelphia, PA, 19104, USA
| | - Alicia L Richards
- Department of Chemistry, Wayne State University, Detroit, MI, 48202, USA
| | | | - Joshua L Fischer
- Department of Chemistry, Wayne State University, Detroit, MI, 48202, USA
| | - Efstathios A Elia
- Department of Chemistry, Wayne State University, Detroit, MI, 48202, USA
| | - Beixi Wang
- Department of Chemistry, Wayne State University, Detroit, MI, 48202, USA
| | | | - Corinne A Lutomski
- Department of Chemistry, Wayne State University, Detroit, MI, 48202, USA
| | - Tarick J El-Baba
- Department of Chemistry, Wayne State University, Detroit, MI, 48202, USA
| | - I-Chung Lu
- Department of Chemistry, Wayne State University, Detroit, MI, 48202, USA
| | - James Wager-Miller
- Gill Center for Biomolecular Science and Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
| | - Ken Mackie
- Gill Center for Biomolecular Science and Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
| | - Charles N McEwen
- MS™, LLC, Newark, DE, 19711, USA
- University of the Sciences, Philadelphia, PA, 19104, USA
| | - Ellen D Inutan
- Department of Chemistry, Wayne State University, Detroit, MI, 48202, USA
- MS™, LLC, Newark, DE, 19711, USA
- Mindanao State University Iligan Institute of Technology, Iligan City, 9200, Philippines
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Trimpin S. Novel ionization processes for use in mass spectrometry: 'Squeezing' nonvolatile analyte ions from crystals and droplets. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2019; 33 Suppl 3:96-120. [PMID: 30138957 DOI: 10.1002/rcm.8269] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 07/29/2018] [Accepted: 08/15/2018] [Indexed: 05/25/2023]
Abstract
Together with my group and collaborators, I have been fortunate to have had a key role in the discovery of new ionization processes that we developed into new flexible, sensitive, rapid, reliable, and robust ionization technologies and methods for use in mass spectrometry (MS). Our current research is focused on how best to understand, improve, and use these novel ionization processes which convert volatile and nonvolatile compounds from solids or liquids into gas-phase ions for analysis by MS using e.g. mass-selected fragmentation and ion mobility spectrometry to provide reproducible, accurate, and improved mass and drift time resolution. In my view, the apex was the discovery of vacuum matrix-assisted ionization (vMAI) in 2012 on an intermediate pressure matrix-assisted laser desorption/ionization (MALDI) source without the use of a laser, high voltages, or any other added energy. Only exposure of the matrix:analyte to the sub-atmospheric pressure of the mass spectrometer was necessary to initiate ionization. These findings were initially rejected by three different scientific journals, with comments related to 'how can this work?', 'where do the charges come from?', and 'it is not analytically useful'. Meanwhile, we and others have demonstrated analytical utility without a complete understanding of the mechanism. In reality, MALDI and electrospray ionization are widely used in science and their mechanisms are still controversially discussed despite use and optimization of now 30 years. This Perspective covers the applications and mechanistic aspects of the novel ionization processes for use in MS that guided us in instrument developments, and provides our perspective on how they relate to traditional ionization processes.
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Affiliation(s)
- Sarah Trimpin
- Department of Chemistry, Wayne State University, Detroit, MI, 48202, USA
- Cardiovascular Research Institute, Wayne State University School of Medicine, Detroit, MI, 48201, USA
- MSTM, LLC, Newark, DE, 19711, USA
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7
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Fenner MA, Chakrabarty S, Wang B, Pagnotti VS, Hoang K, Trimpin S, McEwen CN. An LC/MS Method Providing Improved Sensitivity: Electrospray Ionization Inlet. Anal Chem 2017; 89:4798-4802. [DOI: 10.1021/acs.analchem.6b05172] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Madeline A. Fenner
- Department of Chemistry & Biochemistry, University of the Sciences, Philadelphia, Pennsylvania 19104, United States
| | | | - Beixi Wang
- Department
of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Vincent S. Pagnotti
- Department of Chemistry & Biochemistry, University of the Sciences, Philadelphia, Pennsylvania 19104, United States
| | - Khoa Hoang
- Department of Chemistry & Biochemistry, University of the Sciences, Philadelphia, Pennsylvania 19104, United States
| | - Sarah Trimpin
- Department
of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
- MSTM, LLC, Newark, Delaware 19711, United States
| | - Charles N. McEwen
- Department of Chemistry & Biochemistry, University of the Sciences, Philadelphia, Pennsylvania 19104, United States
- MSTM, LLC, Newark, Delaware 19711, United States
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8
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Chubatyi ND, McEwen CN. Improving the Sensitivity of Matrix-Assisted Ionization (MAI) Mass Spectrometry Using Ammonium Salts. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2015; 26:1649-56. [PMID: 26122522 DOI: 10.1007/s13361-015-1205-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Revised: 05/17/2015] [Accepted: 05/21/2015] [Indexed: 05/03/2023]
Abstract
In matrix-assisted ionization (MAI), analyte incorporated in a small molecule matrix is introduced into an aperture linking atmospheric pressure with the vacuum of a mass spectrometer. Gas-phase analyte ions are spontaneously produced without use of a laser or high voltage. Here we investigate analyte and background ion abundances upon addition of ammonium salts to various MAI matrix/analyte solutions. Regardless of the ammonium salt or matrix used, chemical background ions are suppressed and/or analyte ion abundance improved for basic small molecules, peptides, and proteins. Background ion abundances increase with increasing inlet temperature, but are suppressed with addition of any of a variety of ammonium salts without much effect on the total ion abundances of the analyte ions. However, at lower inlet temperature using the matrices 2-bromo-2-nitropropane-1,3-diol, 1,2-dicyanobenzene, and 3-nitrobenzonitrile (3-NBN), analyte ion abundance increases and any chemical background decreases upon addition of ammonium salt. The improvement in sensitivity using 3-NBN with ammonium salt allows full acquisition mass spectra consuming as little as 1 fmol of ubiquitin. More complete peptide coverage for 100 fmol of a BSA tryptic digest, and increased sensitivity of drugs spiked in urine and saliva were observed after ammonium salt addition to the 3-NBN matrix.
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9
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Wang B, Dearring CL, Wager-Miller J, Mackie K, Trimpin S. Drug detection and quantification directly from tissue using novel ionization methods for mass spectrometry. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2015; 21:201-10. [PMID: 26307700 PMCID: PMC4762651 DOI: 10.1255/ejms.1338] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Solvent assisted ionization inlet (SAII) and matrix assisted ionization vacuum (MAIV) were used to quantify rapidly an antipsychotic drug, clozapine, directly from surfaces with minimal sample preparation. This simple surface analysis method based on SAII- and MAIV-mass spectrometry (MS) was developed to allow the detection of endogenous lipids, metabolites, and clozapine directly from sections of mouse brain tissue. A rapid surface assessment was achieved by SAII with the assistance of heat applied to the mass spectrometer inlet. MAIV provided an improved reproducibility without the need of a heated inlet. In addition, isotope dilution and standard addition were used without sample clean-up, and the results correlate well with liquid chromatography tandem MS using sample work-up. Using the simple surface methods, standard solutions containing clozapine and a deuterated internal standard (clozapine-d8) at different concentration ratios were used in the extraction and quantification of clozapine from brain tissue sections of a drug-treated mouse using different tissue thicknesses. The amount of clozapine extracted by these surface methods was independent of tissue thickness.
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Affiliation(s)
- Beixi Wang
- Department of Chemistry, Wayne State University, Detroit, MI 48202.
| | | | - James Wager-Miller
- Department of Psychological & Brain Sciences, Indiana University, Bloomington, IN 47405.
| | - Ken Mackie
- Department of Psychological & Brain Sciences, Indiana University, Bloomington, IN 47405.
| | - Sarah Trimpin
- Department of Chemistry, Wayne State University, Detroit, MI 48202. Cardiovascular Research Institute, Wayne State University School of Medicine, Detroit, MI 48201.
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Cox JT, Marginean I, Smith RD, Tang K. On the ionization and ion transmission efficiencies of different ESI-MS interfaces. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2015; 26:55-62. [PMID: 25267087 PMCID: PMC4276539 DOI: 10.1007/s13361-014-0998-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 08/19/2014] [Accepted: 08/31/2014] [Indexed: 05/10/2023]
Abstract
The achievable sensitivity of electrospray ionization mass spectrometry (ESI-MS) is largely determined by the ionization efficiency in the ESI source and ion transmission efficiency through the ESI-MS interface. These performance characteristics are difficult to evaluate and compare across multiple platforms as it is difficult to correlate electrical current measurements to actual analyte ions reaching the detector of a mass spectrometer. We present an effective method to evaluate the overall ion utilization efficiency of an ESI-MS interface by measuring the total gas-phase ion current transmitted through the interface and correlating it to the observed ion abundance measured in the corresponding mass spectrum. Using this method, we systematically studied the ion transmission and ionization efficiencies of different ESI-MS interface configurations, including a single emitter/single inlet capillary, single emitter/multi-inlet capillary, and a subambient pressure ionization with nanoelectrospray (SPIN) MS interface with a single emitter and an emitter array, respectively. Our experimental results indicate that the overall ion utilization efficiency of SPIN-MS interface configurations exceeds that of the inlet capillary-based ESI-MS interface configurations.
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11
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Cox JT, Marginean I, Kelly RT, Smith RD, Tang K. Improving the sensitivity of mass spectrometry by using a new sheath flow electrospray emitter array at subambient pressures. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2014; 25:2028-37. [PMID: 24676894 PMCID: PMC4177967 DOI: 10.1007/s13361-014-0856-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 02/11/2014] [Accepted: 02/11/2014] [Indexed: 05/25/2023]
Abstract
Arrays of chemically etched emitters with individualized sheath gas capillaries were developed to enhance electrospray ionization (ESI) efficiency at subambient pressures. By incorporating the new emitter array in a subambient pressure ionization with nanoelectrospray (SPIN) source, both ionization efficiency and ion transmission efficiency were significantly increased, providing enhanced sensitivity in mass spectrometric analyses. The SPIN source eliminates the major ion losses of conventional ESI-mass spectrometry (MS) interfaces by placing the emitter in the first reduced pressure region of the instrument. The new ESI emitter array design developed in this study allows individualized sheath gas around each emitter in the array making it possible to generate an array of uniform and stable electrosprays in the subambient pressure (10 to 30 Torr) environment for the first time. The utility of the new emitter arrays was demonstrated by coupling the emitter array/SPIN source with a time of flight (TOF) mass spectrometer. The instrument sensitivity was compared under different ESI source and interface configurations including a standard atmospheric pressure single ESI emitter/heated capillary, single emitter/SPIN and multi-emitter/SPIN configurations using an equimolar solution of nine peptides. The highest instrument sensitivity was observed using the multi-emitter/SPIN configuration in which the sensitivity increased with the number of emitters in the array. Over an order of magnitude MS sensitivity improvement was achieved using multi-emitter/SPIN compared with using the standard atmospheric pressure single ESI emitter/heated capillary interface.
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12
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Trimpin S, Wang B. Inlet and Vacuum Ionization from Ambient Conditions. AMBIENT IONIZATION MASS SPECTROMETRY 2014. [DOI: 10.1039/9781782628026-00423] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The discovery that laser ablation of a common MALDI matrix at atmospheric pressure without use of a voltage produced ions with nearly identical charge states to ESI led to a series of new ionization methods that we have given the general term inlet and vacuum ionization. The initial thought that the laser was necessary for matrix-assisted ionization gave way to ionization requiring a heated inlet with a pressure-drop region and then to a matrix that could be a solvent or no matrix. This in turn led to laser ablation in vacuum producing multiply charged ions without an inlet, and finally to the present where we have found matrices that lift molecules into the gas phase as ions without any external energy source. Our mechanistic view of this new ionization process developed into ionization methods for use in mass spectrometry will be discussed. These methods are simple to use, safe, robust, and sensitive. Several approaches for high-throughput analyses of compounds irrespective of their molecular weight will be presented using low- and high-performance mass spectrometers.
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Affiliation(s)
- Sarah Trimpin
- Wayne State University, Department of Chemistry Detroit, MI USA
| | - Beixi Wang
- Wayne State University, Department of Chemistry Detroit, MI USA
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13
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El-Baba TJ, Lutomski CA, Wang B, Trimpin S. Characterizing synthetic polymers and additives using new ionization methods for mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2014; 28:1175-1184. [PMID: 24760557 DOI: 10.1002/rcm.6881] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Revised: 02/24/2014] [Accepted: 02/25/2014] [Indexed: 06/03/2023]
Abstract
RATIONALE New inlet and vacuum ionization methods provide advantages of specificity, simplicity and speed for the analysis of synthetic polymers and polymer additives directly from surfaces such as fibers using mass spectrometry (MS) on different commercial mass spectrometers (Waters SYNAPT G2, Thermo LTQ Velos). METHODS We compare inlet ionization methods with the recently discovered vacuum ionization method. This method, termed matrix assisted ionization vacuum (MAIV), utilizes the matrix 3-nitrobenzonitrile (3-NBN) for the analysis of synthetic polymers and additives without additional energy input by simply exposing the matrix:analyte:salt to the vacuum of the mass spectrometer. Matrix:analyte:salt samples can be introduced while dry (surfaces, e.g. glass slides, pipet tips) or slightly wet (e.g. filter paper, pipet tips). RESULTS Compounds ionized by these methods can be analyzed in both positive and negative detection modes through cationization or deprotonation, respectively. The dynamic range of the experiment can be enhanced, as well as structural analysis performed, by coupling the vacuum ionization method with ion mobility spectrometry mass spectrometry (IMS-MS) and tandem mass spectrometric (MS/MS) fragmentation. CONCLUSIONS The specificity of 3-NBN matrix to ionize small and large nonvolatile analyte molecules by MAIV makes this matrix a good choice for observing low-abundance additives in the presence of large amounts of synthetic polymer using MS.
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Affiliation(s)
- Tarick J El-Baba
- Department of Chemistry, Wayne State University, Detroit, MI, 48202, USA
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14
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Recent methodological advances in MALDI mass spectrometry. Anal Bioanal Chem 2014; 406:2261-78. [PMID: 24652146 DOI: 10.1007/s00216-014-7646-6] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 01/17/2014] [Accepted: 01/21/2014] [Indexed: 10/25/2022]
Abstract
Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is widely used for characterization of large, thermally labile biomolecules. Advantages of this analytical technique are high sensitivity, robustness, high-throughput capacity, and applicability to a wide range of compound classes. For some years, MALDI-MS has also been increasingly used for mass spectrometric imaging as well as in other areas of clinical research. Recently, several new concepts have been presented that have the potential to further advance the performance characteristics of MALDI. Among these innovations are novel matrices with low proton affinities for particularly efficient protonation of analyte molecules, use of wavelength-tunable lasers to achieve optimum excitation conditions, and use of liquid matrices for improved quantification. Instrumental modifications have also made possible MALDI-MS imaging with cellular resolution as well as an efficient generation of multiply charged MALDI ions by use of heated vacuum interfaces. This article reviews these recent innovations and gives the author's personal outlook of possible future developments.
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15
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Wang B, Trimpin S. High-throughput solvent assisted ionization inlet for use in mass spectrometry. Anal Chem 2013; 86:1000-6. [PMID: 24093975 DOI: 10.1021/ac400867b] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In this work we developed a multiplexed analysis platform providing a simple high-throughput means to characterize solutions. Automated analyses, requiring less than 5 s per sample without carryover and 1 s per sample, accepting minor cross contamination, was achieved using multiplexed solvent assisted ionization inlet (SAII) mass spectrometry (MS). The method involves sequentially moving rows of pipet tips containing sample solutions in close proximity to the inlet aperture of a heated mass spectrometer inlet tube. The solution is pulled from the container into the mass spectrometer inlet by the pressure differential at the mass spectrometer inlet aperture. This sample introduction method for direct injection of solutions is fast, easily implemented, and widely applicable, as is shown by applications ranging from small molecules to proteins as large as carbonic anhydrase (molecular weight ca. 29,000). MS/MS fragmentation is applicable for sample characterization. An x,y-stage and common imaging software are incorporated to map the location of components in the sample wells of a microtiter plate. Location within an x,y-array of different sample solutions and the relative concentration of the sample are displayed using ion intensity maps.
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Affiliation(s)
- Beixi Wang
- Department of Chemistry, Wayne State University , 5101 Cass Avenue, Detroit, Michigan 48202, United States
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16
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Trimpin S, Wang B, Lietz CB, Marshall DD, Richards AL, Inutan ED. New ionization processes and applications for use in mass spectrometry. Crit Rev Biochem Mol Biol 2013; 48:409-29. [DOI: 10.3109/10409238.2013.806887] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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17
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Lietz CB, Gemperline E, Li L. Qualitative and quantitative mass spectrometry imaging of drugs and metabolites. Adv Drug Deliv Rev 2013; 65:1074-85. [PMID: 23603211 DOI: 10.1016/j.addr.2013.04.009] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Revised: 03/27/2013] [Accepted: 04/09/2013] [Indexed: 12/26/2022]
Abstract
Mass spectrometric imaging (MSI) has rapidly increased its presence in the pharmaceutical sciences. While quantitative whole-body autoradiography and microautoradiography are the traditional techniques for molecular imaging of drug delivery and metabolism, MSI provides advantageous specificity that can distinguish the parent drug from metabolites and modified endogenous molecules. This review begins with the fundamentals of MSI sample preparation/ionization, and then moves on to both qualitative and quantitative applications with special emphasis on drug discovery and delivery. Cutting-edge investigations on sub-cellular imaging and endogenous signaling peptides are also highlighted, followed by perspectives on emerging technology and the path for MSI to become a routine analysis technique.
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18
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Haapala M, Suominen T, Kostiainen R. Capillary Photoionization: A High Sensitivity Ionization Method for Mass Spectrometry. Anal Chem 2013; 85:5715-9. [DOI: 10.1021/ac4002673] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Markus Haapala
- Division of Pharmaceutical Chemistry,
Faculty of Pharmacy, University of Helsinki, P.O. Box 56, FIN-00014 Viikinkaari
5 E, Finland
| | - Tina Suominen
- Division of Pharmaceutical Chemistry,
Faculty of Pharmacy, University of Helsinki, P.O. Box 56, FIN-00014 Viikinkaari
5 E, Finland
| | - Risto Kostiainen
- Division of Pharmaceutical Chemistry,
Faculty of Pharmacy, University of Helsinki, P.O. Box 56, FIN-00014 Viikinkaari
5 E, Finland
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19
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Trimpin S, Inutan ED. Matrix assisted ionization in vacuum, a sensitive and widely applicable ionization method for mass spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2013; 24:722-32. [PMID: 23526166 DOI: 10.1007/s13361-012-0571-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Revised: 12/07/2012] [Accepted: 12/14/2012] [Indexed: 05/25/2023]
Abstract
An astonishingly simple new method to produce gas-phase ions of small molecules as well as proteins from the solid state under cold vacuum conditions is described. This matrix assisted ionization vacuum (MAIV) mass spectrometry (MS) method produces multiply charged ions similar to those that typify electrospray ionization (ESI) and uses sample preparation methods that are nearly identical to matrix-assisted laser desorption/ionization (MALDI). Unlike these established methods, MAIV does not require a laser or voltage for ionization, and unlike the recently introduced matrix assisted ionization inlet method, does not require added heat. MAIV-MS requires only introduction of a crystalline mixture of the analyte incorporated with a suitable small molecule matrix compound such as 3-nitrobenzonitrile directly to the vacuum of the mass spectrometer. Vacuum intermediate pressure MALDI sources and modified ESI sources successfully produce ions for analysis by MS with this method. As in ESI-MS, ion formation is continuous and, without a laser, little chemical background is observed. MAIV, operating from a surface offers the possibility of significantly improved sensitivity relative to atmospheric pressure ionization because ions are produced in the vacuum region of the mass spectrometer eliminating losses associated with ion transfer from atmospheric pressure to vacuum. Mechanistic aspects and potential applications for this new ionization method are discussed.
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Affiliation(s)
- Sarah Trimpin
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA.
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Zhang Y, Fonslow BR, Shan B, Baek MC, Yates JR. Protein analysis by shotgun/bottom-up proteomics. Chem Rev 2013; 113:2343-94. [PMID: 23438204 PMCID: PMC3751594 DOI: 10.1021/cr3003533] [Citation(s) in RCA: 979] [Impact Index Per Article: 89.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Yaoyang Zhang
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Bryan R. Fonslow
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Bing Shan
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Moon-Chang Baek
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA
- Department of Molecular Medicine, Cell and Matrix Biology Research Institute, School of Medicine, Kyungpook National University, Daegu 700-422, Republic of Korea
| | - John R. Yates
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA
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21
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The potential for clinical applications using a new ionization method combined with ion mobility spectrometry-mass spectrometry. ACTA ACUST UNITED AC 2013. [DOI: 10.1007/s12127-013-0131-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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22
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Pagnotti VS, Chakrabarty S, McEwen CN. Carbonation and other super saturated gases as solution modifiers for improved sensitivity in solvent assisted ionization inlet (SAII) and ESI. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2013; 24:186-92. [PMID: 23296909 DOI: 10.1007/s13361-012-0535-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 10/31/2012] [Accepted: 11/04/2012] [Indexed: 05/25/2023]
Abstract
Solvent Assisted Ionization Inlet (SAII) produces ions in a heated inlet to a mass spectrometer from aqueous and aqueous/organic solutions with high sensitivity. However, the use of acid modifiers, which typically aids electrospray ionization, generally results in ion suppression in SAII. Here we demonstrate that the use of carbonation and other super-saturated gases as solution modifiers increases analyte ion abundance and reduces metal cation adduction in SAII. Carbonation is also found to enhance electrospray ionization. The mechanistic and practical utility of carbonation in mass spectrometry is addressed.
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Li J, Inutan ED, Wang B, Lietz CB, Green DR, Manly CD, Richards AL, Marshall DD, Lingenfelter S, Ren Y, Trimpin S. Matrix assisted ionization: new aromatic and nonaromatic matrix compounds producing multiply charged lipid, peptide, and protein ions in the positive and negative mode observed directly from surfaces. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2012; 23:1625-43. [PMID: 22895857 DOI: 10.1007/s13361-012-0413-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 05/09/2012] [Accepted: 05/11/2012] [Indexed: 05/25/2023]
Abstract
Matrix assisted inlet ionization (MAII) is a method in which a matrix:analyte mixture produces mass spectra nearly identical to electrospray ionization without the application of a voltage or the use of a laser as is required in laserspray ionization (LSI), a subset of MAII. In MAII, the sample is introduced by, for example, tapping particles of dried matrix:analyte into the inlet of the mass spectrometer and, therefore, permits the study of conditions pertinent to the formation of multiply charged ions without the need of absorption at a laser wavelength. Crucial for the production of highly charged ions are desolvation conditions to remove matrix molecules from charged matrix:analyte clusters. Important factors affecting desolvation include heat, vacuum, collisions with gases and surfaces, and even radio frequency fields. Other parameters affecting multiply charged ion production is sample preparation, including pH and solvent composition. Here, findings from over 100 compounds found to produce multiply charged analyte ions using MAII with the inlet tube set at 450 °C are presented. Of the compounds tested, many have -OH or -NH(2) functionality, but several have neither (e.g., anthracene), nor aromaticity or conjugation. Binary matrices are shown to be applicable for LSI and solvent-free sample preparation can be applied to solubility restricted compounds, and matrix compounds too volatile to allow drying from common solvents. Our findings suggest that the physical properties of the matrix such as its morphology after evaporation of the solvent, its propensity to evaporate/sublime, and its acidity are more important than its structure and functional groups.
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Affiliation(s)
- Jing Li
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA
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24
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Trimpin S, Wang B, Inutan ED, Li J, Lietz CB, Harron A, Pagnotti VS, Sardelis D, McEwen CN. A mechanism for ionization of nonvolatile compounds in mass spectrometry: considerations from MALDI and inlet ionization. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2012; 23:1644-60. [PMID: 22791582 DOI: 10.1007/s13361-012-0414-y] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 05/09/2012] [Accepted: 05/11/2012] [Indexed: 05/12/2023]
Abstract
Mechanistic arguments relative to matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) address observations that predominately singly charged ions are detected. However, recently a matrix assisted laser ablation method, laserspray ionization (LSI), was introduced that can use the same sample preparation and laser as MALDI, but produce highly charged ions from proteins. In MALDI, ions are generated from neutral molecules by the photon energy provided to a matrix, while in LSI ions are produced inside a heated inlet tube linking atmospheric pressure and the first vacuum region of the mass spectrometer. Some LSI matrices also produce highly charged ions with MALDI ion sources operated at intermediate pressure or high vacuum. The operational similarity of LSI to MALDI, and the large difference in charge states observed by these methods, provides information of fundamental importance to proposed ionization mechanisms for LSI and MALDI. Here, we present data suggesting that the prompt and delayed ionization reported for vacuum MALDI are both fast processes relative to producing highly charged ions by LSI. The energy supplied to produce these charged clusters/droplets as well as their size and time available for desolvation are determining factors in the charge states of the ions observed. Further, charged droplets/clusters may be a common link for ionization of nonvolatile compounds by a variety of MS ionization methods, including MALDI and LSI.
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Affiliation(s)
- Sarah Trimpin
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA.
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25
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Pagnotti VS, Chakrabarty S, Harron AF, McEwen CN. Increasing the Sensitivity of Liquid Introduction Mass Spectrometry by Combining Electrospray Ionization and Solvent Assisted Inlet Ionization. Anal Chem 2012; 84:6828-32. [DOI: 10.1021/ac3014115] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Vincent S. Pagnotti
- University of the Sciences, Department of Chemistry & Biochemistry, Philadelphia, Pennsylvania 19104, United States
| | - Shubhashis Chakrabarty
- University of the Sciences, Department of Chemistry & Biochemistry, Philadelphia, Pennsylvania 19104, United States
| | - Andrew F. Harron
- University of the Sciences, Department of Chemistry & Biochemistry, Philadelphia, Pennsylvania 19104, United States
| | - Charles N. McEwen
- University of the Sciences, Department of Chemistry & Biochemistry, Philadelphia, Pennsylvania 19104, United States
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26
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Chubatyi ND, Pagnotti VS, Bentzley CM, McEwen CN. High sensitivity steroid analysis using liquid chromatography/solvent-assisted inlet ionization mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2012; 26:887-92. [PMID: 22396024 DOI: 10.1002/rcm.6179] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
RATIONALE Steroids can be injected to behave as therapeutic agents to promote muscle growth and strength. Areas of concern include synthetic steroids in consumer meat and milk products and the presence of anabolic steroids in athletes. Here we demonstrate a new ionization method for high sensitivity steroid analysis using liquid chromatography/mass spectrometry (LC/MS). METHODS Solvent-assisted inlet ionization (SAII) mass spectrometry was coupled directly to an infusion pump or to a liquid chromatograph to determine the limits of detection and quantitation for selected steroids. LC/MS/MS data was acquired on a quadrupole time-of-flight (QTOF) mass spectrometer and high resolution-accurate mass LC/MS data was obtained on an Orbitrap mass spectrometer. RESULTS The SAII limit of detection for infusion into the Orbitrap using high mass resolution and accurate mass was shown, for the steroids studied, to be low ppqt and the limit of quantitation using LC/MS was low ppt. Low ppb levels were detected with high signal-to-noise from spiked urine using a simple Ziptip procedure without sample concentration. CONCLUSIONS LC/SAII-MS is more sensitive than electrospray ionization (ESI) at similar mobile phase flow rates for the analysis of steroids. Previous studies have shown LC/SAII-MS to have high sensitivity for analysis of peptides. The combined results suggests this easy to implement ionization method may advantageously replace ESI for a wide range of analyses.
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27
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Richards AL, Lietz CB, Wager-Miller J, Mackie K, Trimpin S. Localization and imaging of gangliosides in mouse brain tissue sections by laserspray ionization inlet. J Lipid Res 2012; 53:1390-8. [PMID: 22262808 DOI: 10.1194/jlr.d019711] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A new ionization method for the analysis of fragile gangliosides without undesired fragmentation or salt adduction is presented. In laserspray ionization inlet (LSII), the matrix/analyte sample is ablated at atmospheric pressure, and ionization takes place in the ion transfer capillary of the mass spectrometer inlet by a process that is independent of a laser wavelength or voltage. The softness of LSII allows the identification of gangliosides up to GQ1 with negligible sialic acid loss. This is of importance to the field of MS imaging, as undesired fragmentation has made it difficult to accurately map the spatial distribution of fragile ganglioside lipids in tissue. Proof-of-principle structural characterization of endogenous gangliosides using MS(n) fragmentation of multiply charged negative ions on a LTQ Velos and subsequent imaging of the GD1 ganglioside is demonstrated. This is the first report of multiply charged negative ions using inlet ionization. We find that GD1 is detected at higher levels in the mouse cortex and hippocampus compared with the thalamus. In LSII with the laser aligned in transmission geometry relative to the inlet, images were obtained in approximately 60 min using an inexpensive nitrogen laser.
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Affiliation(s)
- Alicia L Richards
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA
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