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Trimpin S, Inutan ED, Pagnotti VS, Karki S, Marshall DD, Hoang K, Wang B, Lietz CB, Richards AL, Yenchick FS, Lee C, Lu IC, Fenner M, Madarshahian S, Saylor S, Chubatyi ND, Zimmerman T, Moreno-Pedraza A, Wang T, Adeniji-Adele A, Meher AK, Madagedara H, Owczarzak Z, Musavi A, Hendrickson TL, Peacock PM, Tomsho JW, Larsen BS, Prokai L, Shulaev V, Pophristic M, McEwen CN. Direct sub-atmospheric pressure ionization mass spectrometry: Evaporation/sublimation-driven ionization is amazing, fundamentally, and practically. JOURNAL OF MASS SPECTROMETRY : JMS 2024; 59:e5018. [PMID: 38736378 DOI: 10.1002/jms.5018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 12/08/2023] [Accepted: 03/04/2024] [Indexed: 05/14/2024]
Abstract
This paper covers direct sub-atmospheric pressure ionization mass spectrometry (MS). The discovery, applications, and mechanistic aspects of novel ionization processes for use in MS that are not based on the high-energy input from voltage, laser, and/or high temperature but on sublimation/evaporation within a region linking a higher to lower pressure and modulated by heat and collisions, are discussed, including how this new reality has guided a series of discoveries, instrument developments, and commercialization. A research focus, inter alia, is on how best to understand, improve, and use these novel ionization processes, which convert volatile and nonvolatile compounds from solids (sublimation) or liquids (evaporation) into gas-phase ions for analysis by MS providing reproducible, accurate, sensitive, and prompt results. Our perception on how these unprecedented versus traditional ionization processes/methods relate to each other, how they can be made to coexist on the same mass spectrometer, and an outlook on new and expanded applications (e.g., clinical, portable, fast, safe, and autonomous) is presented, and is based on ST's Opening lecture presentation at the Nordic Mass spectrometry Conference, Geilo, Norway, January 2023. Focus will be on matrix-assisted ionization (MAI) and solvent-assisted ionization (SAI) MS covering the period from 2010 to 2023; a potential paradigm shift in the making.
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Affiliation(s)
- Sarah Trimpin
- Department of Chemistry, Wayne State University, Detroit, Michigan, USA
- MSTM, LLC, Newark, Delaware, USA
| | - Ellen D Inutan
- Department of Chemistry, Wayne State University, Detroit, Michigan, USA
- MSTM, LLC, Newark, Delaware, USA
- Mindanao State University-Iligan Institute of Technology, Iligan City, Philippines
| | - Vincent S Pagnotti
- Department of Chemistry & Biochemistry, Saint Joseph's University, Philadelphia, Pennsylvania, USA
| | - Santosh Karki
- Department of Chemistry, Wayne State University, Detroit, Michigan, USA
- MSTM, LLC, Newark, Delaware, USA
| | - Darrell D Marshall
- Department of Chemistry, Wayne State University, Detroit, Michigan, USA
- MSTM, LLC, Newark, Delaware, USA
| | - Khoa Hoang
- MSTM, LLC, Newark, Delaware, USA
- Department of Chemistry & Biochemistry, Saint Joseph's University, Philadelphia, Pennsylvania, USA
| | - Beixi Wang
- Department of Chemistry, Wayne State University, Detroit, Michigan, USA
| | | | - Alicia L Richards
- Department of Chemistry, Wayne State University, Detroit, Michigan, USA
| | - Frank S Yenchick
- Department of Chemistry, Wayne State University, Detroit, Michigan, USA
| | - Chuping Lee
- Department of Chemistry, Wayne State University, Detroit, Michigan, USA
| | - I-Chung Lu
- Department of Chemistry, Wayne State University, Detroit, Michigan, USA
- Department of Chemistry, National Chung Hsing University, Taichung, Taiwan
| | - Madeleine Fenner
- Department of Chemistry & Biochemistry, Saint Joseph's University, Philadelphia, Pennsylvania, USA
| | - Sara Madarshahian
- Department of Chemistry & Biochemistry, Saint Joseph's University, Philadelphia, Pennsylvania, USA
| | - Sarah Saylor
- Department of Chemistry & Biochemistry, Saint Joseph's University, Philadelphia, Pennsylvania, USA
| | - Nicolas D Chubatyi
- Department of Chemistry & Biochemistry, Saint Joseph's University, Philadelphia, Pennsylvania, USA
| | - Teresa Zimmerman
- Department of Chemistry, Wayne State University, Detroit, Michigan, USA
| | | | - Tongwen Wang
- Department of Chemistry & Biochemistry, Saint Joseph's University, Philadelphia, Pennsylvania, USA
| | - Adetoun Adeniji-Adele
- Department of Chemistry & Biochemistry, Saint Joseph's University, Philadelphia, Pennsylvania, USA
| | - Anil K Meher
- Department of Chemistry, Wayne State University, Detroit, Michigan, USA
- MSTM, LLC, Newark, Delaware, USA
| | - Hasini Madagedara
- Department of Chemistry, Wayne State University, Detroit, Michigan, USA
| | - Zachary Owczarzak
- Department of Chemistry, Wayne State University, Detroit, Michigan, USA
| | - Ahmed Musavi
- Department of Chemistry, Wayne State University, Detroit, Michigan, USA
| | | | | | - John W Tomsho
- Department of Chemistry & Biochemistry, Saint Joseph's University, Philadelphia, Pennsylvania, USA
| | | | - Laszlo Prokai
- Department of Pharmacology and Neuroscience, The University of North Texas Health Science Center at Forth Worth, Fort Worth, Texas, USA
| | - Vladimir Shulaev
- Department of Biological Sciences, The University of North Texas, Denton, Texas, USA
| | - Milan Pophristic
- MSTM, LLC, Newark, Delaware, USA
- Department of Chemistry & Biochemistry, Saint Joseph's University, Philadelphia, Pennsylvania, USA
| | - Charles N McEwen
- MSTM, LLC, Newark, Delaware, USA
- Department of Chemistry & Biochemistry, Saint Joseph's University, Philadelphia, Pennsylvania, USA
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2
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Cho YT, Su H, Wu CY, Huang TL, Jeng J, Huang MZ, Wu DC, Shiea J. Molecular Mapping of Sebaceous Squalene by Ambient Mass Spectrometry. Anal Chem 2021; 93:16608-16617. [PMID: 34860507 DOI: 10.1021/acs.analchem.1c03983] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Squalene (SQ), a highly unsaturated sebaceous lipid, plays an important role in protecting human skin. To better understand the role of SQ in clinical medicine, an efficient analytical approach is needed to comprehensively study the distribution of SQ on different parts of the skin. In this study, sebaceous lipids were collected from different epidermal areas of a volunteer with sampling probes. Thermal desorption-electrospray ionization/mass spectrometry (TD-ESI/MS) was then used to characterize the lipid species on the probes, and each TD-ESI/MS analysis was completed within a few seconds without any sample pretreatment. The molecular mapping of epidermal squalene on whole-body skin was rendered by scaling the peak area of the extracted ion current (EIC) of SQ based on a temperature color gradient, where colors were assigned to the 1357 sampling locations on a 3D map of the volunteer. The image showed a higher SQ distribution on the face than any other area of the body, indicating the role of SQ in protecting facial skin. The results were in agreement with previous studies using SQ as a marker to explore sebaceous activity. The novelty and significance of this work are concluded as two points: (1) direct and rapid detection of all major classes of sebaceous lipids, including the unsaturated hydrocarbons (SQ) and nonpolar lipids (e.g., cholesterol). The results are unique compared to other conventional and ambient ionization mass spectrometry methods and (2) this is the first study to analyze SQ distribution on the whole-body skin by a high-throughput approach.
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Affiliation(s)
- Yi-Tzu Cho
- Department of Cosmetic Applications and Management, Yuh-Ing Junior College of Health Care & Management, No. 15, Lane 420, Dachang 2nd Road, Sanmin District, Kaohsiung 807634, Taiwan
| | - Hung Su
- Department of Chemistry, National Sun Yat-Sen University, No. 70, Lienhai Road, Gushan District, Kaohsiung 804201, Taiwan
| | - Ching-Ying Wu
- Department of Dermatology, College of Medicine, Kaohsiung Medical University, Kaohsiung 807378, Taiwan.,Department of Dermatology, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung 801735, Taiwan.,Department of Cosmetic Science, Chang Gung University of Science and Technology, Taoyuan 333324, Taiwan
| | - Tiao-Lai Huang
- Department of Psychiatry, Chang Gung Memorial Hospital-Kaohsiung Medical Center and Chang Gung University College of Medicine, Kaohsiung 833401, Taiwan.,Genomic and Proteomic Core Laboratory, Department of Medical Research, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 833401, Taiwan
| | - Jingyueh Jeng
- Department of Medicinal Chemistry, Chia Nan University of Pharmacy and Science, Tainan 717301, Taiwan
| | - Min-Zong Huang
- Department of Chemistry, National Sun Yat-Sen University, No. 70, Lienhai Road, Gushan District, Kaohsiung 804201, Taiwan
| | - Deng-Chyang Wu
- Division of Gastroenterology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 807378, Taiwan.,Regenerative Medicine and Cell Therapy Research Center, Kaohsiung Medical University, Kaohsiung 807378, Taiwan.,Department of Medicine, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807378, Taiwan
| | - Jentaie Shiea
- Department of Chemistry, National Sun Yat-Sen University, No. 70, Lienhai Road, Gushan District, Kaohsiung 804201, Taiwan.,Research Center for Environmental Medicine, Kaohsiung Medical University, Kaohsiung 807378, Taiwan.,Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 807378, Taiwan
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3
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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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Trimpin S, Pophristic M, Adeniji-Adele A, Tomsho JW, McEwen CN. Vacuum Matrix-Assisted Ionization Source Offering Simplicity, Sensitivity, and Exceptional Robustness in Mass Spectrometry. Anal Chem 2018; 90:11188-11192. [DOI: 10.1021/acs.analchem.8b03378] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Sarah Trimpin
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
- Cardiovascular Research Institute, School of Medicine, Wayne State University, Detroit, Michigan 48202, United States
- MSTM LLC, Newark, Delaware 19711, United States
| | | | - Adetoun Adeniji-Adele
- Department of Chemistry & Biochemistry, University of the Sciences, Philadelphia, Pennsylvania 19104, United States
| | - John W. Tomsho
- Department of Chemistry & Biochemistry, University of the Sciences, Philadelphia, Pennsylvania 19104, United States
| | - Charles N. McEwen
- MSTM LLC, Newark, Delaware 19711, United States
- Department of Chemistry & Biochemistry, University of the Sciences, Philadelphia, Pennsylvania 19104, United States
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Motoyama A, Kihara K. Mass Spectrometry in Cosmetic Science: Advanced Ionization Techniques for Detecting Trace Molecules in or on Human Skin. ACTA ACUST UNITED AC 2017; 6:S0071. [PMID: 28959516 DOI: 10.5702/massspectrometry.s0071] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 07/19/2017] [Indexed: 01/08/2023]
Abstract
To provide safe and effective products to customers in the cosmetic industry, mass spectrometry (MS) is an indispensable analytical tool. In addition to its outstanding sensitivity and specificity, the method is applicable to a wide variety of compounds, which makes it irreplaceable for the development of cosmetics, which requires the analysis of complex systems. Because most cosmetic products are applied directly to the skin and function as they are designed, monitoring the molecular compositions of endogenous or exogenous compounds in or on the skin is crucial to ensure the safety and efficacy of a cosmetic product. Recent advancements in MS and ionization techniques, such as MS imaging and ambient ionization, now provide access to richer and deeper molecular information with less time and effort. This brief review discusses advanced ionization techniques that are currently used in the field of cosmetic science using two examples, namely, the use of desorption electrospray ionization and zero-volt paperspray ionization to detect trace molecules in or on human skin.
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Affiliation(s)
| | - Keishi Kihara
- Shiseido Global Innovation Center, Shiseido Co., Ltd
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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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Meher AK, Chen YC. Electrospray Modifications for Advancing Mass Spectrometric Analysis. ACTA ACUST UNITED AC 2017; 6:S0057. [PMID: 28573082 DOI: 10.5702/massspectrometry.s0057] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 12/30/2016] [Indexed: 11/23/2022]
Abstract
Generation of analyte ions in gas phase is a primary requirement for mass spectrometric analysis. One of the ionization techniques that can be used to generate gas phase ions is electrospray ionization (ESI). ESI is a soft ionization method that can be used to analyze analytes ranging from small organics to large biomolecules. Numerous ionization techniques derived from ESI have been reported in the past two decades. These ion sources are aimed to achieve simplicity and ease of operation. Many of these ionization methods allow the flexibility for elimination or minimization of sample preparation steps prior to mass spectrometric analysis. Such ion sources have opened up new possibilities for taking scientific challenges, which might be limited by the conventional ESI technique. Thus, the number of ESI variants continues to increase. This review provides an overview of ionization techniques based on the use of electrospray reported in recent years. Also, a brief discussion on the instrumentation, underlying processes, and selected applications is also presented.
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Affiliation(s)
| | - Yu-Chie Chen
- Department of Applied Chemistry, National Chiao Tung University
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Affiliation(s)
- Patricia M Peacock
- First State IR, LLC , 118 Susan Drive, Hockessin, Delaware 19707, United States
| | - Wen-Jing Zhang
- Department of Chemistry, Wayne State University , 5101 Cass Avenue, Detroit, Michigan 48202, United States
| | - Sarah Trimpin
- Department of Chemistry, Wayne State University , 5101 Cass Avenue, Detroit, Michigan 48202, United States
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Meher AK, Chen YC. Combination of Raman Spectroscopy and Mass Spectrometry for Online Chemical Analysis. Anal Chem 2016; 88:9151-7. [PMID: 27571682 DOI: 10.1021/acs.analchem.6b02152] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Mass spectrometry (MS) and Raman spectroscopy are complementary analytical techniques used to provide information related to chemical structures and functional groups of target analytes. Each instrument provides specific chemical information. If these two analytical tools are coupled online, comprehensive structural information can be simultaneously collected from the analytes of interest without losing any important chemical information. Nevertheless, exploring a suitable interface for coupling of these analytical tools, which are governed with different operation principles, remains challenging. In this study, we used a small piece of tissue paper as an interface for hyphenating a Raman spectroscope and a mass spectrometer online. The paper played multiroles as sample loading substrate and an emitter to generate electrospray. Furthermore, it can facilitate surface-enhanced Raman spectroscopic analysis to improve analyte signals in Raman spectra. A sample droplet was placed on the tissue paper located close to the laser of the Raman spectroscope and the inlet of mass spectrometer. Raman spectra were first collected by the Raman spectroscope through laser irradiation followed by generation of electrospray on the edge of the paper for MS analysis. Positional isomers were used as model samples to demonstrate the effectiveness of the hyphenated analytical tool in distinguishing isomers. The feasibility of using this Raman-MS hyphenated technique for monitoring chemical reactions online in real time was also investigated.
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Affiliation(s)
- Anil Kumar Meher
- Department of Applied Chemistry, National Chiao Tung University , Hsinchu 300, Taiwan
| | - Yu-Chie Chen
- Department of Applied Chemistry, National Chiao Tung University , Hsinchu 300, Taiwan
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Trimpin S. "Magic" Ionization Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2016; 27:4-21. [PMID: 26486514 PMCID: PMC4686549 DOI: 10.1007/s13361-015-1253-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Revised: 08/05/2015] [Accepted: 08/12/2015] [Indexed: 05/11/2023]
Abstract
The systematic study of the temperature and pressure dependence of matrix-assisted ionization (MAI) led us to the discovery of the seemingly impossible, initially explained by some reviewers as either sleight of hand or the misinterpretation by an overzealous young scientist of results reported many years before and having little utility. The “magic” that we were attempting to report was that with matrix assistance, molecules, at least as large as bovine serum albumin (66 kDa), are lifted into the gas phase as multiply charged ions simply by exposure of the matrix:analyte sample to the vacuum of a mass spectrometer. Applied heat, a laser, or voltages are not necessary to achieve charge states and ion abundances only previously observed with electrospray ionization (ESI). The fundamentals of how solid phase volatile or nonvolatile compounds are converted to gas-phase ions without added energy currently involves speculation providing a great opportunity to rethink mechanistic understanding of ionization processes used in mass spectrometry. Improved understanding of the mechanism(s) of these processes and their connection to ESI and matrix-assisted laser desorption/ionization may provide opportunities to further develop new ionization strategies for traditional and yet unforeseen applications of mass spectrometry. This Critical Insights article covers developments leading to the discovery of a seemingly magic ionization process that is simple to use, fast, sensitive, robust, and can be directly applied to surface characterization using portable or high performance mass spectrometers.
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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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