1
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An SJ, Kal Y, Jeong M, Kang S, Kwak B, Kim H, Ryu S, Cha S. Simple Protein Analysis by Droplet Paper Spray Ionization Mass Spectrometry with Polyolefin Silica-Based Paper. Molecules 2023; 28:7339. [PMID: 37959759 PMCID: PMC10647424 DOI: 10.3390/molecules28217339] [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] [Received: 09/27/2023] [Revised: 10/27/2023] [Accepted: 10/28/2023] [Indexed: 11/15/2023] Open
Abstract
Paper spray ionization mass spectrometry (PSI MS) has emerged as a notable method for the rapid analysis of biological samples. However, the typical cellulose-based paper tip is incompatible with protein detection due to the strong interaction between cellulose hydroxyl groups and proteins. In this study, we utilized a commercially available polyolefin-based synthetic paper, Teslin®, as an alternative PSI substrate for simple protein analysis. We have named this method "droplet PSI" MS, as the aqueous protein solution droplet retains its shape on the Teslin® paper tip. For droplet PSI, no further chemical pretreatment was necessary for the Teslin® substrate; the only required preparation was shaping the Teslin® paper into a triangular tip. In droplet PSI MS, protein ion signals were instantly detected from a protein solution droplet upon applying a spray solvent in situ along with high voltage (HV). When compared with conventional PSI MS, our method demonstrated superior sensitivity. The droplet PSI MS utilizing Teslin® also showcased flexibility in real-time observation of protein alterations induced by an acid additive. Additionally, the effects of spray solvent composition and the application method were discussed.
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Affiliation(s)
| | | | | | | | | | | | | | - Sangwon Cha
- Department of Chemistry, Dongguk University, Seoul 04620, Republic of Korea
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2
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Liu C, Wang Q, Hivick BE, Ai Y, Champagne PA, Pan Y, Chen H. Capture of Electrochemically Generated Fleeting Carbazole Radical Cations and Elucidation of Carbazole Dimerization Mechanism by Mass Spectrometry. Anal Chem 2020; 92:15291-15296. [PMID: 33084312 DOI: 10.1021/acs.analchem.0c01223] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The capture of reactive intermediates is important for the elucidation of reaction mechanisms. We report the first observation of electrochemically generated, short-lived radical cations of carbazole (t1/2 ≈ 97 μs) and two N-substituted carbazole derivatives by mass spectrometry. In addition, online investigation of the reactivity of electrochemically generated carbazole radical cations supports that the carbazole dimerization mechanism involves the reaction of one radical cation with one neutral molecule rather than the previously proposed coupling of two radical cations.
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Affiliation(s)
- Chengyuan Liu
- Department of Chemistry & Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102, United States.,National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, China
| | - Qi Wang
- Department of Chemistry & Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102, United States
| | - Brian E Hivick
- Department of Chemistry & Biochemistry, Ohio University, Athens, Ohio 45701, United States
| | - Yongling Ai
- Department of Chemistry & Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102, United States
| | - Pier Alexandre Champagne
- Department of Chemistry & Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102, United States
| | - Yang Pan
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, China
| | - Hao Chen
- Department of Chemistry & Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102, United States.,Department of Chemistry & Biochemistry, Ohio University, Athens, Ohio 45701, United States
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3
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Hu B, Yao ZP. Detection of native proteins using solid-substrate electrospray ionization mass spectrometry with nonpolar solvents. Anal Chim Acta 2018; 1004:51-57. [DOI: 10.1016/j.aca.2017.11.079] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 11/23/2017] [Accepted: 11/24/2017] [Indexed: 12/11/2022]
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4
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Wang H, Yong G, Brown SL, Lee HE, Zenaidee MA, Supuran CT, Donald WA. Supercharging protein ions in native mass spectrometry using theta capillary nanoelectrospray ionization mass spectrometry and cyclic alkylcarbonates. Anal Chim Acta 2018; 1003:1-9. [DOI: 10.1016/j.aca.2017.11.075] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 11/22/2017] [Accepted: 11/25/2017] [Indexed: 12/27/2022]
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5
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Lu M, Su Y, Zhao P, Ye X, Cai Y, Shi X, Masson E, Li F, Campbell JL, Chen H. Direct Evidence for the Origin of Bis-Gold Intermediates: Probing Gold Catalysis with Mass Spectrometry. Chemistry 2018; 24:2144-2150. [PMID: 29131927 PMCID: PMC6139295 DOI: 10.1002/chem.201703666] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Indexed: 11/11/2022]
Abstract
Gold-catalyzed alkyne hydration was studied by using in situ reacting mass spectrometry (MS) technology. By monitoring the reaction process in solution under different conditions (regular and very diluted catalyst concentrations, different pH values) and examining the reaction occurrence in the early reaction stage (1-2 ms after mixing) with MS, we collected a series of experimental evidence to support that the bis-gold complex is a potential key reaction intermediate. Furthermore, both experimental and computational studies confirmed that the σ,π-bis-gold complexes are not active intermediates toward nucleophilic addition. Instead, formation of geminally diaurated complex C is crucial for this catalytic process.
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Affiliation(s)
- Mei Lu
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry & Edison Institute of Biology, Ohio University, Athens, OH, 45701, USA
| | - Yijin Su
- Department of Chemistry, University of South Florida, Tampa, FL, 33620, USA
| | - Pengyi Zhao
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry & Edison Institute of Biology, Ohio University, Athens, OH, 45701, USA
| | - Xiaohan Ye
- Department of Chemistry, University of South Florida, Tampa, FL, 33620, USA
| | - Yi Cai
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry & Edison Institute of Biology, Ohio University, Athens, OH, 45701, USA
| | - Xiaodong Shi
- Department of Chemistry, University of South Florida, Tampa, FL, 33620, USA
| | - Eric Masson
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry & Edison Institute of Biology, Ohio University, Athens, OH, 45701, USA
| | - Fengyao Li
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry & Edison Institute of Biology, Ohio University, Athens, OH, 45701, USA
| | - J Larry Campbell
- AB Sciex, 71 Four Valley Drive, Concord, Ontario, L4K 4V8, Canada
| | - Hao Chen
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry & Edison Institute of Biology, Ohio University, Athens, OH, 45701, USA
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6
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Cheng S, Wu Q, Dewald HD, Chen H. Online Monitoring of Methanol Electro-Oxidation Reactions by Ambient Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:1005-1012. [PMID: 27562502 DOI: 10.1007/s13361-016-1450-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Revised: 05/25/2016] [Accepted: 07/10/2016] [Indexed: 06/06/2023]
Abstract
Online detection of methanol electro-oxidation reaction products [e.g., formaldehyde (HCHO)] by mass spectrometry (MS) is challenging, owing to the high salt content and extreme pH of the electrolyte solution as well as the difficulty in ionizing the reaction products. Herein we present an online ambient mass spectrometric approach for analyzing HCHO generated from methanol electro-oxidation, taking the advantage of high salt tolerance of desorption electrospray ionization mass spectrometry (DESI-MS). It was found that HCHO can be detected as PhNHNH+=CH2 (m/z 121) by DESI after online derivatization with PhNHNH2. With this approach, the analysis of HCHO from methanol electro-oxidation by MS was carried out not only in acidic condition but also in alkaline media for the first time. Efficiencies of different electrodes for methanol oxidation at different pHs were also evaluated. Our results show that Au electrode produces more HCHO than Pt-based electrodes at alkaline pH, while the latter have higher yields at acidic solution. The presented methodology would be of great value for elucidating fuel cell reaction mechanisms and for screening ideal fuel cell electrode materials. Graphical Abstract ᅟ.
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Affiliation(s)
- Si Cheng
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, OH, 45701, USA
| | - Qiuhua Wu
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, OH, 45701, USA
- College of Sciences, Agricultural University of Hebei, Baoding, Hebei, 071001, China
| | - Howard D Dewald
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, OH, 45701, USA.
| | - Hao Chen
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, OH, 45701, USA.
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7
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Investigating the structural transitions of proteins during dissolution by mass spectrometry. Talanta 2017; 164:418-426. [DOI: 10.1016/j.talanta.2016.11.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 11/07/2016] [Accepted: 11/09/2016] [Indexed: 11/17/2022]
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8
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Cheng S, Wu Q, Xiao H, Chen H. Online Monitoring of Enzymatic Reactions Using Time-Resolved Desorption Electrospray Ionization Mass Spectrometry. Anal Chem 2017; 89:2338-2344. [DOI: 10.1021/acs.analchem.6b03975] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Si Cheng
- Center
for Intelligent Chemical Instrumentation, Department of Chemistry
and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, Ohio 45701, United States,
| | - Qiuhua Wu
- Center
for Intelligent Chemical Instrumentation, Department of Chemistry
and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, Ohio 45701, United States,
- Department
of Chemistry, College of Science, Agricultural University of Hebei, Baoding 071001, China
| | - He Xiao
- Center
for Intelligent Chemical Instrumentation, Department of Chemistry
and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, Ohio 45701, United States,
| | - Hao Chen
- Center
for Intelligent Chemical Instrumentation, Department of Chemistry
and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, Ohio 45701, United States,
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9
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Yuill EM, Baker LA. Electrochemical Aspects of Mass Spectrometry: Atmospheric Pressure Ionization and Ambient Ionization for Bioanalysis. ChemElectroChem 2017. [DOI: 10.1002/celc.201600751] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Elizabeth M. Yuill
- Department of Chemistry; Indiana University; 800 E. Kirkwood Avenue Bloomington, Indiana 47405 USA
| | - Lane A. Baker
- Department of Chemistry; Indiana University; 800 E. Kirkwood Avenue Bloomington, Indiana 47405 USA
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10
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Zheng Q, Chen H. Development and Applications of Liquid Sample Desorption Electrospray Ionization Mass Spectrometry. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2016; 9:411-448. [PMID: 27145689 DOI: 10.1146/annurev-anchem-071015-041620] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Desorption electrospray ionization mass spectrometry (DESI-MS) is a recent advance in the field of analytical chemistry. This review surveys the development of liquid sample DESI-MS (LS-DESI-MS), a variant form of DESI-MS that focuses on fast analysis of liquid samples, and its novel analy-tical applications in bioanalysis, proteomics, and reaction kinetics. Due to the capability of directly ionizing liquid samples, liquid sample DESI (LS-DESI) has been successfully used to couple MS with various analytical techniques, such as microfluidics, microextraction, electrochemistry, and chromatography. This review also covers these hyphenated techniques. In addition, several closely related ionization methods, including transmission mode DESI, thermally assisted DESI, and continuous flow-extractive DESI, are briefly discussed. The capabilities of LS-DESI extend and/or complement the utilities of traditional DESI and electrospray ionization and will find extensive and valuable analytical application in the future.
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Affiliation(s)
- Qiuling Zheng
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, and Edison Biotechnology Institute, Ohio University, Athens, Ohio 45701;
| | - Hao Chen
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, and Edison Biotechnology Institute, Ohio University, Athens, Ohio 45701;
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11
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Cheng S, Wang J, Cai Y, Loo JA, Chen H. Enhancing Performance of Liquid Sample Desorption Electrospray Ionization Mass Spectrometry Using Trap and Capillary Columns. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 2015; 392:73-79. [PMID: 27239159 PMCID: PMC4878830 DOI: 10.1016/j.ijms.2015.09.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Desorption electrospray ionization mass spectrometry (DESI-MS) is a recent and important advance in the field that has extensive applications in surface analysis of solid samples but has also been extended to analysis of liquid samples. The liquid sample DESI typically employs a piece of fused silica capillary to transfer liquid sample for ionization. In this study, we present the improvement of liquid sample DESI-MS by replacing the sample transfer silica capillary with a trap column filled with chromatographic stationary phase materials (e.g., C4, C18). This type of trap column/liquid sample DESI can be used for trace analysis of organics and biomolecules such as proteins/peptides (in nM concentration) in high salt content matrices. Furthermore, when the sample transfer capillary is modified with enzyme covalently bound on its inside capillary wall, fast digestion (< 6 min) of proteins such as phosphoproteins can be achieved and the online digested proteins can be directly ionized using DESI with high sensitivity. The latter is ascribed to the freedom to select favorable spray solvent for the DESI analysis. Our data shows that liquid sample DESI-MS with a modified sample transfer capillary has significantly expanded its utility in bioanalysis.
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Affiliation(s)
- Si Cheng
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, OH, 45701, USA
| | - Jun Wang
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, OH, 45701, USA ; Department of forensic science, Jiangsu Police Institute, Nanjing, Jiang Su, 210031, China
| | - Yi Cai
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, OH, 45701, USA
| | - Joseph A Loo
- Department of Chemistry and Biochemistry, Department of Biological Chemistry, David Geffen School of Medicine at UCLA, and UCLA/DOE Institute for Genomics and Proteomics, University of California-Los Angeles, Los Angeles, California 90095, USA
| | - Hao Chen
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, OH, 45701, USA
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12
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Zheng Q, Liu Y, Chen Q, Hu M, Helmy R, Sherer EC, Welch CJ, Chen H. Capture of Reactive Monophosphine-Ligated Palladium(0) Intermediates by Mass Spectrometry. J Am Chem Soc 2015; 137:14035-8. [DOI: 10.1021/jacs.5b08905] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Qiuling Zheng
- Center
for Intelligent Chemical Instrumentation, Department of Chemistry
and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, Ohio 45701, United States
| | - Yong Liu
- Department of Process and Analytical Chemistry and Department of Structural Chemistry, Merck Research Laboratories, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Qinghao Chen
- Department of Process and Analytical Chemistry and Department of Structural Chemistry, Merck Research Laboratories, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Meihong Hu
- Center
for Intelligent Chemical Instrumentation, Department of Chemistry
and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, Ohio 45701, United States
| | - Roy Helmy
- Department of Process and Analytical Chemistry and Department of Structural Chemistry, Merck Research Laboratories, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Edward C. Sherer
- Department of Process and Analytical Chemistry and Department of Structural Chemistry, Merck Research Laboratories, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Christopher J. Welch
- Department of Process and Analytical Chemistry and Department of Structural Chemistry, Merck Research Laboratories, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Hao Chen
- Center
for Intelligent Chemical Instrumentation, Department of Chemistry
and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, Ohio 45701, United States
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13
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Kulyk DS, Miller CF, Badu-Tawiah AK. Reactive Charged Droplets for Reduction of Matrix Effects in Electrospray Ionization Mass Spectrometry. Anal Chem 2015; 87:10988-94. [PMID: 26437455 DOI: 10.1021/acs.analchem.5b02943] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Dmytro S. Kulyk
- Department of Chemistry and
Biochemistry, The Ohio State University, 100 West 18th Ave, Columbus, Ohio 43210, United States
| | - Colbert F. Miller
- Department of Chemistry and
Biochemistry, The Ohio State University, 100 West 18th Ave, Columbus, Ohio 43210, United States
| | - Abraham K. Badu-Tawiah
- Department of Chemistry and
Biochemistry, The Ohio State University, 100 West 18th Ave, Columbus, Ohio 43210, United States
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14
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Liu YM, Perry RH. Paper-Based Electrochemical Cell Coupled to Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2015; 26:1702-1712. [PMID: 26311335 DOI: 10.1007/s13361-015-1224-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 06/15/2015] [Accepted: 06/17/2015] [Indexed: 06/04/2023]
Abstract
On-line coupling of electrochemistry (EC) to mass spectrometry (MS) is a powerful approach for identifying intermediates and products of EC reactions in situ. In addition, EC transformations have been used to increase ionization efficiency and derivatize analytes prior to MS, improving sensitivity and chemical specificity. Recently, there has been significant interest in developing paper-based electroanalytical devices as they offer convenience, low cost, versatility, and simplicity. This report describes the development of tubular and planar paper-based electrochemical cells (P-EC) coupled to sonic spray ionization (SSI) mass spectrometry (P-EC/SSI-MS). The EC cells are composed of paper sandwiched between two mesh stainless steel electrodes. Analytes and reagents can be added directly to the paper substrate along with electrolyte, or delivered via the SSI microdroplet spray. The EC cells are decoupled from the SSI source, allowing independent control of electrical and chemical parameters. We utilized P-EC/SSI-MS to characterize various EC reactions such as oxidations of cysteine, dopamine, polycyclic aromatic hydrocarbons, and diphenyl sulfide. Our results show that P-EC/SSI-MS has the ability to increase ionization efficiency, to perform online EC transformations, and to capture intermediates of EC reactions with a response time on the order of hundreds of milliseconds. The short response time allowed detection of a deprotonated diphenyl sulfide intermediate, which experimentally confirms a previously proposed mechanism for EC oxidation of diphenyl sulfide to pseudodimer sulfonium ion. This report introduces paper-based EC/MS via development of two device configurations (tubular and planar electrodes), as well as discusses the capabilities, performance, and limitations of the technique.
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Affiliation(s)
- Yao-Min Liu
- Department of Chemistry, University of Illinois, Urbana, IL, 61801, USA
| | - Richard H Perry
- Department of Chemistry, University of Illinois, Urbana, IL, 61801, USA.
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15
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Lu M, Liu Y, Helmy R, Martin GE, Dewald HD, Chen H. Online Investigation of Aqueous-Phase Electrochemical Reactions by Desorption Electrospray Ionization Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2015; 26:1676-1685. [PMID: 26242804 DOI: 10.1007/s13361-015-1210-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 05/16/2015] [Accepted: 05/29/2015] [Indexed: 06/04/2023]
Abstract
Electrochemistry (EC) combined with mass spectrometry (MS) is a powerful tool for elucidation of electrochemical reaction mechanisms. However, direct online analysis of electrochemical reaction in aqueous phase was rarely explored. This paper presents the online investigation of several electrochemical reactions with biological relevance in the aqueous phase, such as nitrosothiol reduction, carbohydrate oxidation, and carbamazepine oxidation using desorption electrospray ionization mass spectrometry (DESI-MS). It was found that electroreduction of nitrosothiols [e.g., nitrosylated insulin B (13-23)] leads to free thiols by loss of NO, as confirmed by online MS analysis for the first time. The characteristic mass shift of 29 Da and the reduced intensity provide a quick way to identify nitrosylated species. Equally importantly, upon collision-induced dissociation (CID), the reduced peptide ion produces more fragment ions than its nitrosylated precursor ion (presumably the backbone fragmentation cannot compete with the facile NO loss for the precursor ion), thus facilitating peptide sequencing. In the case of saccharide oxidation, it was found that glucose undergoes electro-oxidation to produce gluconic acid at alkaline pH, but not at neutral and acidic pHs. Such a pH-dependent electrochemical behavior was also observed for disaccharides such as maltose and cellobiose. Upon electrochemical oxidation, carbamazepine was found to undergo ring contraction and amide bond cleavage, which parallels the oxidative metabolism observed for this drug in leucocytes. The mechanistic information of these redox reactions revealed by EC/DESI-MS would be of value in nitroso-proteome research and carbohydrate/drug metabolic studies.
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Affiliation(s)
- Mei Lu
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, OH, 45701, USA
| | - Yong Liu
- Department of Process and Analytical Chemistry, Merck Research Laboratories, Merck and Co., Inc., Rahway, NJ, 07065, USA.
| | - Roy Helmy
- Department of Process and Analytical Chemistry, Merck Research Laboratories, Merck and Co., Inc., Rahway, NJ, 07065, USA
| | - Gary E Martin
- Department of Process and Analytical Chemistry, Merck Research Laboratories, Merck and Co., Inc., Rahway, NJ, 07065, USA
| | - Howard D Dewald
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, OH, 45701, USA
| | - Hao Chen
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, OH, 45701, USA.
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16
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Brown TA, Chen H, Zare RN. Identification of Fleeting Electrochemical Reaction Intermediates Using Desorption Electrospray Ionization Mass Spectrometry. J Am Chem Soc 2015; 137:7274-7. [DOI: 10.1021/jacs.5b03862] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Timothy A. Brown
- Department
of Chemistry, Stanford University, Stanford, California 94305-5080, United States
| | - Hao Chen
- Center
for Intelligent Chemical Instrumentation, Department of Chemistry
and Biochemistry, and Edison Biotechnology Institute, Ohio University, Athens, Ohio 45701-2979, United States
| | - Richard N. Zare
- Department
of Chemistry, Stanford University, Stanford, California 94305-5080, United States
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17
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Cai Y, Zheng Q, Liu Y, Helmy R, Loo JA, Chen H. Integration of electrochemistry with ultra-performance liquid chromatography/mass spectrometry. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2015; 21:341-51. [PMID: 26307715 PMCID: PMC4552337 DOI: 10.1255/ejms.1318] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
This study presents the development of ultra-performance liquid chromatography (UPLC) mass spectrometry (MS) combined with electrochemistry (EC) for the first time and its application for the structural analysis of proteins/peptides that contain disulfide bonds. In our approach, a protein/peptide mixture sample undergoes a fast UPLC separation and subsequent electrochemical reduction in an electrochemical flow cell followed by online MS and tandem mass spectrometry (MS/MS) analyses. The electrochemical cell is coupled to the mass spectrometer using our recently developed desorption electrospray ionization (DESI) interface. Using this UPLC/EC/DESI-MS method, peptides that contain disulfide bonds can be differentiated from those without disulfide bonds, as the former are electroactive and reducible. MS/MS analysis of the disulfide-reduced peptide ions provides increased information on the sequence and disulfide-linkage pattern. In a reactive DESI- MS detection experiment in which a supercharging reagent was used to dope the DESI spray solvent, increased charging was obtained for the UPLC-separated proteins. Strikingly, upon online electrolytic reduction, supercharged proteins (e.g., α-lactalbumin) showed even higher charging, which will be useful in top- down protein structure MS analysis as increased charges are known to promote protein ion dissociation. Also, the separation speed and sensitivity are enhanced by approximately 1(~)2 orders of magnitude by using UPLC for the liquid chromatography (LC)/EC/MS platform, in comparison to the previously used high- performance liquid chromatography (HPLC). This UPLC/EC/DESI-MS method combines the power of fast UPLC separation, fast electrochemical conversion, and online MS structural analysis for a potentially valuable tool for proteomics research and bioanalysis.
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Affiliation(s)
- Yi Cai
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, OH, 45701 USA.
| | - Qiuling Zheng
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, OH, 45701 USA.
| | - Yong Liu
- Department of Analytical Chemistry, Merck Research Laboratories, Merck & Co., Inc., Rahway, NJ 07065, USA.
| | - Roy Helmy
- Department of Analytical Chemistry, Merck Research Laboratories, Merck & Co., Inc., Rahway, NJ 07065, USA.
| | - Joseph A Loo
- Dep artment of Chemistry and Biochemistry, Department of Biological Chemistry, David Geffen School of Medicine at UCLA, and UCLA/DOE Institute for Genomics and Proteomics, University of California-Los Angeles, Los Angeles, CA 90095, USA.
| | - Hao Chen
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, OH, 45701 USA.
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18
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Yao Y, Shams-Ud-Doha K, Daneshfar R, Kitova EN, Klassen JS. Quantifying protein-carbohydrate interactions using liquid sample desorption electrospray ionization mass spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2015; 26:98-106. [PMID: 25315460 DOI: 10.1007/s13361-014-1008-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Revised: 09/03/2014] [Accepted: 09/05/2014] [Indexed: 06/04/2023]
Abstract
The application of liquid sample desorption electrospray ionization mass spectrometry (liquid sample DESI-MS) for quantifying protein-carbohydrate interactions in vitro is described. Association constants for the interactions between lysozyme and β-D-GlcNAc-(1 → 4)-β-D-GlcNAc-(1 → 4)-D-GlcNAc and β-D-GlcNAc-(1 → 4)-β-D-GlcNAc-(1 → 4)-β-D-GlcNAc-(1 → 4)-D-GlcNAc, and between a single chain antibody and α-D-Galp-(1 → 2)-[α-D-Abep-(1 → 3)]-α-D-Manp-OCH3 and β-D-Glcp-(1 → 2)-[α-D-Abep-(1 → 3)]-α-D-Manp-OCH3 measured using liquid sample DESI-MS were found to be in good agreement with values measured by isothermal titration calorimetry and the direct ESI-MS assay. The reference protein method, which was originally developed to correct ESI mass spectra for the occurrence of nonspecific ligand-protein binding, was shown to reliably correct liquid sample DESI mass spectra for nonspecific binding. The suitability of liquid sample DESI-MS for quantitative binding measurements carried out using solutions containing high concentrations of the nonvolatile biological buffer phosphate buffered saline (PBS) was also explored. Binding of lysozyme to β-D-GlcNAc-(1 → 4)-β-D-GlcNAc-(1 → 4)-D-GlcNAc in aqueous solutions containing up to 1× PBS was successfully monitored using liquid sample DESI-MS; with ESI-MS the binding measurements were limited to concentrations less than 0.02 X PBS.
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Affiliation(s)
- Yuyu Yao
- Alberta Glycomics Center and Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada
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19
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Chen LC, Rahman MM, Hiraoka K. Super-Atmospheric Pressure Ion Sources: Application and Coupling to API Mass Spectrometer. Mass Spectrom (Tokyo) 2014; 3:S0024. [PMID: 26819896 DOI: 10.5702/massspectrometry.s0024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 11/28/2013] [Indexed: 11/23/2022] Open
Abstract
Pressurizing the ionization source to gas pressure greater than atmospheric pressure is a new tactic aimed at further improving the performance of atmospheric pressure ionization (API) sources. In principle, all API sources, such as ESI, APCI and AP-MALDI, can be operated at pressure higher than 1 atm if suitable vacuum interface is available. The gas pressure in the ion source can have different role for different ionization. For example, in the case of ESI, stable electrospray could be sustained for high surface tension liquid (e.g., pure water) under super-atmospheric pressure, owing to the absence of electric discharge. Even for nanoESI, which is known to work well with aqueous solution, its stability and sensitivity were found to be enhanced, particularly in the negative mode when the ion source was pressurized. For the gas phase ionization like APCI, measurement of gaseous compound also showed an increase in ion intensity with the ion source pressure until an optimum pressure at around 4-5 atm. The enhancement was due to the increased collision frequency among reactant ion and analyte that promoted the ion/molecule reaction and a higher intake rate of gas to the mass spectrometer. Because the design of vacuum interface for API instrument is based on the upstream pressure of 1 atm, some coupling aspects need to be considered when connecting the high pressure ion source to the mass spectrometer. Several coupling strategies are discussed in this paper.
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Affiliation(s)
- Lee Chuin Chen
- Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi
| | | | - Kenzo Hiraoka
- Clean Energy Research Center, University of Yamanashi
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Fisher CM, Kharlamova A, McLuckey SA. Affecting Protein Charge State Distributions in Nano-Electrospray Ionization via In-Spray Solution Mixing Using Theta Capillaries. Anal Chem 2014; 86:4581-8. [PMID: 24702054 DOI: 10.1021/ac500721r] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Christine M. Fisher
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907-2084, United States
| | - Anastasia Kharlamova
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907-2084, United States
| | - Scott A. McLuckey
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907-2084, United States
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21
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Montowska M, Rao W, Alexander MR, Tucker GA, Barrett DA. Tryptic digestion coupled with ambient desorption electrospray ionization and liquid extraction surface analysis mass spectrometry enabling identification of skeletal muscle proteins in mixtures and distinguishing between beef, pork, horse, chicken, and turkey meat. Anal Chem 2014; 86:4479-87. [PMID: 24673366 DOI: 10.1021/ac5003432] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The use of ambient desorption electrospray ionization mass spectrometry (DESI-MS) and liquid extraction surface analysis mass spectrometry (LESA-MS) is explored for the first time to analyze skeletal muscle proteins obtained from a mixture of standard proteins and raw meat. Single proteins and mixtures of up to five proteins (myoglobin, troponin C, actin, bovine serum albumin (BSA), tropomyosin) were deposited onto a polymer surface, followed by in situ tryptic digestion and comparative analysis using DESI-MS and LESA-MS using tandem electrospray MS. Peptide peaks specific to individual proteins were readily distinguishable with good signal-to-noise ratio in the five-component mixture. LESA-MS gave a more stable analysis and greater sensitivity compared with DESI-MS. Meat tryptic digests were subjected to peptidomics analysis by DESI-MS and LESA-MS. Bovine, horse, pig, chicken, and turkey muscle digests were clearly discriminated using multivariate data analysis (MVA) of the peptidomic data sets. The most abundant skeletal muscle proteins were identified and correctly classified according to the species following MS/MS analysis. The study shows, for the first time, that ambient ionization techniques such as DESI-MS and LESA-MS have great potential for species-specific analysis and differentiation of skeletal muscle proteins by direct surface desorption.
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Affiliation(s)
- Magdalena Montowska
- Centre for Analytical Bioscience, School of Pharmacy, University of Nottingham , University Park, Nottingham NG7 2RD, United Kingdom
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22
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Cai Y, Adams D, Chen H. A new splitting method for both analytical and preparative LC/MS. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2014; 25:286-92. [PMID: 24254577 DOI: 10.1007/s13361-013-0763-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 09/18/2013] [Accepted: 09/28/2013] [Indexed: 05/28/2023]
Abstract
This paper presents a novel splitting method for liquid chromatography/mass spectrometry (LC/MS) application, which allows fast MS detection of LC-separated analytes and subsequent online analyte collection. In this approach, a PEEK capillary tube with a micro-orifice drilled on the tube side wall is used to connect with LC column. A small portion of LC eluent emerging from the orifice can be directly ionized by desorption electrospray ionization (DESI) with negligible time delay (6~10 ms) while the remaining analytes exiting the tube outlet can be collected. The DESI-MS analysis of eluted compounds shows narrow peaks and high sensitivity because of the extremely small dead volume of the orifice used for LC eluent splitting (as low as 4 nL) and the freedom to choose favorable DESI spray solvent. In addition, online derivatization using reactive DESI is possible for supercharging proteins and for enhancing their signals without introducing extra dead volume. Unlike UV detector used in traditional preparative LC experiments, this method is applicable to compounds without chromophores (e.g., saccharides) due to the use of MS detector. Furthermore, this splitting method well suits monolithic column-based ultra-fast LC separation at a high elution flow rate of 4 mL/min. Figure ᅟ
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Affiliation(s)
- Yi Cai
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Ohio University, Athens, OH, 45701, USA
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23
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Rahman MM, Hiraoka K, Chen LC. Realizing nano electrospray ionization using disposable pipette tips under super atmospheric pressure. Analyst 2014; 139:610-7. [DOI: 10.1039/c3an01635h] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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24
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Liu P, Zhang J, Ferguson CN, Chen H, Loo JA. Measuring protein-ligand interactions using liquid sample desorption electrospray ionization mass spectrometry. Anal Chem 2013; 85:11966-72. [PMID: 24237005 PMCID: PMC3901310 DOI: 10.1021/ac402906d] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
We have previously shown that liquid sample desorption electrospray ionization-mass spectrometry (DESI-MS) is able to measure large proteins and noncovalently bound protein complexes (to 150 kDa) (Ferguson et al., Anal. Chem. 2011, 83, 6468-6473). In this study, we further investigate the application of liquid sample DESI-MS to probe protein-ligand interactions. Liquid sample DESI allows the direct formation of intact protein-ligand complex ions by spraying ligands toward separate protein sample solutions. This type of "reactive" DESI methodology can provide rapid information on binding stiochiometry, selectivity, and kinetics, as demonstrated by the binding of ribonuclease A (RNaseA, 13.7 kDa) with cytidine nucleotide ligands and the binding of lysozyme (14.3 kDa) with acetyl chitose ligands. A higher throughput method for ligand screening by liquid sample DESI was demonstrated, in which different ligands were sequentially injected as a segmented flow for DESI ionization. Furthermore, supercharging to enhance analyte charge can be integrated with liquid sample DESI-MS, without interfering with the formation of protein-ligand complexes.
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Affiliation(s)
- Pengyuan Liu
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California 90095, United States
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, United States
| | - Jiang Zhang
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California 90095, United States
| | - Carly N. Ferguson
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California 90095, United States
| | - Hao Chen
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, United States
| | - Joseph A. Loo
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California 90095, United States
- Department of Biological Chemistry, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, California 90095, United States
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25
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Zheng Q, Zhang H, Chen H. Integration of online digestion and electrolytic reduction with mass spectrometry for rapid disulfide-containing protein structural analysis. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 2013; 353:84-92. [PMID: 25419170 PMCID: PMC4240030 DOI: 10.1016/j.ijms.2013.04.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Bottom-up structural analysis of disulfide-bond containing proteins usually involves time-consuming offline enzymatic digestion, chemical reduction and thiol protection prior to mass spectrometric detection, which takes many hours. This paper presents an expedited bottom-up approach, employing desorption electrospray ionization-mass spectrometry (DESI-MS) coupled with online pepsin digestion and online electrochemical reduction of disulfide bonds. Peptides are generated in high digestion yield as its precursor protein in acidic aqueous solution flows through a pepsin column, which can undergo direct electrolysis. The electrolytic behaviors of peptides, as online monitored by DESI-MS, suggest the presence or absence of disulfide bonds in the peptides, and also provide information to relate disulfide bond-containing peptide precursors to their corresponding reduced products. Furthermore, selective electrolysis simply using different reduction potentials can be adopted to generate either partially or fully reduced peptides to assist disulfide bond mapping. In addition, it turns out that DESI is suitable for ionizing peptides in water without organic solvent additives (organic solvent additives would not be compatible with the use of pepsin column). The feasibility of this method was demonstrated using insulin, a protein carrying three pairs of disulfide-bonds as an example, in which all disulfide bond linkages and most of the protein sequence were successfully determined. Strikingly, this method shortens the sample digestion, reduction and MS detection from hours to less than 7 min, which could be of high value in high-throughput proteomics research.
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Affiliation(s)
- Qiuling Zheng
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Ohio University, Athens, OH 45701, USA
| | - Hao Zhang
- Department of Chemistry, Washington University, St. Louis, MO 63130, USA
- Corresponding author. Tel.: +1 314 935 7486
| | - Hao Chen
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Ohio University, Athens, OH 45701, USA
- Corresponding author. Tel.: +1 740 593 0719; fax: +1 740 597 3157
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26
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Li L, Yang SH, Lemr K, Havlicek V, Schug KA. Continuous flow-extractive desorption electrospray ionization: Analysis from “non-electrospray ionization-friendly” solvents and related mechanism. Anal Chim Acta 2013; 769:84-90. [DOI: 10.1016/j.aca.2013.01.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 01/07/2013] [Accepted: 01/11/2013] [Indexed: 11/25/2022]
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27
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Liu J, Zhang C, Sun J, Ren X, Luo H. Laser desorption dual spray post-ionization mass spectrometry for direct analysis of samples via two informative channels. JOURNAL OF MASS SPECTROMETRY : JMS 2013; 48:250-254. [PMID: 23378098 DOI: 10.1002/jms.3145] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2012] [Revised: 11/08/2012] [Accepted: 11/20/2012] [Indexed: 06/01/2023]
Abstract
A laser desorption dual spray post-ionization mass spectrometry method is described, and its usefulness is demonstrated with the examples of selective detection of food components, manipulation of protein charge state distribution and investigation on the formation of magic number clusters. The method is carried out by adopting two spray emitters for post-ionization of analytes desorbed by a pulsed infrared laser. Various components in a complex sample or distinct behavior of an analyte in two different spray reagents can be rapidly probed by the method quasi-simultaneously, highlighting the potential applications of this method for protein characterization, reaction study and food analysis.
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Affiliation(s)
- Jia Liu
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
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28
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Liu P, Lu M, Zheng Q, Zhang Y, Dewald HD, Chen H. Recent advances of electrochemical mass spectrometry. Analyst 2013; 138:5519-39. [DOI: 10.1039/c3an00709j] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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29
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Moore BN, Hamdy O, Julian RR. Protein structure evolution in liquid DESI as revealed by selective noncovalent adduct protein probing. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 2012; 330-332:220-225. [PMID: 23526115 PMCID: PMC3601934 DOI: 10.1016/j.ijms.2012.08.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Previous experiments based on charge state distributions have suggested that liquid desorption electrospray ionization (DESI) is capable of preserving solution phase protein structure during transfer to the gas phase (Journal of the American Society for Mass Spectrometry 21 (2010) 1730-1736). In order to examine this possibility more carefully, we have utilized selective non-covalent adduct protein probing (SNAPP) to evaluate protein structural evolution in both liquid DESI and standard ESI under a variety of conditions. Experiments with cytochrome c (Cytc) demonstrated that methanol induced conformational shifts previously observed with ESI are also easily observed with liquid DESI. However, undesirable acid-induced unfolding becomes apparent at very high concentrations of methanol in liquid DESI due to acetic acid in the spray solvent, suggesting that there are conditions under which liquid DESI will not preserve solution phase structure. The effects of ammonium acetate buffer on liquid DESI SNAPP experiments were examined by monitoring structural changes in myoglobin. Heme retention and SNAPP distributions were both preserved better in liquid DESI than traditional ESI, suggesting superior performance for liquid DESI in buffered conditions. Finally, liquid DESI SNAPP was used to study the natively disordered proteins α, β, and γ synuclein with SNAPP. α-Synuclein, the main component of fibrils found in patients with Parkinson's disease, yielded a significantly different SNAPP distribution compared to β and γ synuclein. This difference is indicative of highly accessible protonated basic side chains, a property known to promote fibril formation in proteins.
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Affiliation(s)
| | | | - Ryan R. Julian
- Corresponding author. Tel.: +1 951 827 3958. (R.R. Julian)
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30
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Yao ZP. Characterization of proteins by ambient mass spectrometry. MASS SPECTROMETRY REVIEWS 2012; 31:437-47. [PMID: 21898526 DOI: 10.1002/mas.20346] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 06/07/2011] [Accepted: 06/19/2011] [Indexed: 05/16/2023]
Abstract
Proteins play important roles in living systems and are topics of many fundamental and applied research projects. With the introduction of electrospray ionization and matrix-assisted laser desorption/ionization for analysis of biomacromolecules in the late 1980s, mass spectrometry has become an important tool for characterization of proteins. Characterization of proteins in raw samples by these mass spectrometric techniques, however, usually requires extensive sample pretreatment. Ambient ionization techniques are new mass spectrometric techniques that allow direct analysis of samples with no or little sample preparation. Can these techniques facilitate or even eliminate sample preparation for mass spectrometric analysis of proteins? Apart from sample preparation, do these techniques offer any new features for characterization of proteins as compared with conventional ESI or MALDI? Recent advances in characterization of proteins by ambient mass spectrometry are summarized and commented in this article.
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Affiliation(s)
- Zhong-Ping Yao
- State Key Laboratory for Chirosciences, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, China.
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31
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Lu M, Wolff C, Cui W, Chen H. Investigation of some biologically relevant redox reactions using electrochemical mass spectrometry interfaced by desorption electrospray ionization. Anal Bioanal Chem 2012; 403:355-65. [PMID: 22237914 PMCID: PMC3731448 DOI: 10.1007/s00216-011-5679-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 12/12/2011] [Accepted: 12/18/2011] [Indexed: 10/14/2022]
Abstract
Recently we have shown that, as a versatile ionization technique, desorption electrospray ionization (DESI) can serve as a useful interface to combine electrochemistry (EC) with mass spectrometry (MS). In this study, the EC/DESI-MS method has been further applied to investigate some aqueous phase redox reactions of biological significance, including the reduction of peptide disulfide bonds and nitroaromatics as well as the oxidation of phenothiazines. It was found that knotted/enclosed disulfide bonds in the peptides apamin and endothelin could be electrochemically cleaved. Subsequent tandem MS analysis of the resulting reduced peptide ions using collision-induced dissociation (CID) and electron-capture dissociation (ECD) gave rise to extensive fragment ions, providing a fast protocol for sequencing peptides with complicated disulfide bond linkages. Flunitrazepam and clonazepam, a class of nitroaromatic drugs, are known to undergo reduction into amines which was proposed to involve nitroso and N-hydroxyl intermediates. Now in this study, these corresponding intermediate ions were successfully intercepted and their structures were confirmed by CID. This provides mass spectrometric evidence for the mechanism of the nitro to amine conversion process during nitroreduction, an important redox reaction involved in carcinogenesis. In addition, the well-known oxidation reaction of chlorpromazine was also examined. The putative transient one-electron transfer product, the chlorpromazine radical cation (m/z 318), was captured by MS, for the first time, and its structure was also verified by CID. In addition to these observations, some features of the DESI-interfaced electrochemical mass spectrometry were discussed, such as simple instrumentation and the lack of background signal. These results further demonstrate the feasibility of EC/DESI-MS for the study of the biology-relevant redox chemistry and would find applications in proteomics and drug development research.
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Affiliation(s)
- Mei Lu
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Ohio University, Athens, OH 45701, USA
| | - Chloe Wolff
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Ohio University, Athens, OH 45701, USA
| | - Weidong Cui
- Department of Chemistry, Washington University, St. Louis, MO 63130, USA
| | - Hao Chen
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Ohio University, Athens, OH 45701, USA
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Wang Z, Zhang Y, Zhang H, Harrington PB, Chen H. Fast and selective modification of thiol proteins/peptides by N-(phenylseleno)phthalimide. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2012; 23:520-9. [PMID: 22223263 PMCID: PMC3704154 DOI: 10.1007/s13361-011-0317-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2011] [Revised: 12/03/2011] [Accepted: 12/07/2011] [Indexed: 05/15/2023]
Abstract
We previously reported that selenamide reagents such as ebselen and N-(phenylseleno)phthalimide (NPSP) can be used to selectively derivatize thiols for mass spectrometric analysis, and the introduced selenium tags are useful as they could survive or removed with collision-induced dissociation (CID). Described herein is the further study of the reactivity of various protein/peptide thiols toward NPSP and its application to derivatize thiol peptides in protein digests. With a modified protocol (i.e., dissolving NPSP in acetonitrile instead of aqueous solvent), we found that quantitative conversion of thiols can be obtained in seconds, using NPSP in a slight excess amount (NPSP:thiol of 1.1-2:1). Further investigation shows that the thiol reactivity toward NPSP reflects its chemical environment and accessibility in proteins/peptides. For instance, adjacent basic amino acid residues increase the thiol reactivity, probably because they could stabilize the thiolate form to facilitate the nucleophilic attack of thiol on NPSP. In the case of creatine phosphokinase, the native protein predominately has one thiol reacted with NPSP while all of four thiol groups of the denatured protein can be derivatized, in accordance with the corresponding protein conformation. In addition, thiol peptides in protein/peptide enzymatic digests can be quickly and effectively tagged by NPSP following tri-n-butylphosphine (TBP) reduction. Notably, all three thiols of the peptide QCCASVCSL in the insulin peptic digest can be modified simultaneously by NPSP. These results suggest a novel and selective method for protecting thiols in the bottom-up approach for protein structure analysis.
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Affiliation(s)
- Zhengfang Wang
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Ohio University, Athens, OH 45701, USA
| | - Yun Zhang
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Ohio University, Athens, OH 45701, USA
| | - Hao Zhang
- Department of Chemistry, Washington University, St. Louis, MO 63130, USA
| | - Peter B. Harrington
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Ohio University, Athens, OH 45701, USA
| | - Hao Chen
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Ohio University, Athens, OH 45701, USA
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D'Aloise P, Chen H. Rapid determination of flunitrazepam in alcoholic beverages by desorption electrospray ionization-mass spectrometry. Sci Justice 2012; 52:2-8. [DOI: 10.1016/j.scijus.2011.08.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Revised: 08/10/2011] [Accepted: 08/22/2011] [Indexed: 11/24/2022]
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Transient Ru-methyl formate intermediates generated with bifunctional transfer hydrogenation catalysts. Proc Natl Acad Sci U S A 2012; 109:2246-50. [PMID: 22315417 DOI: 10.1073/pnas.1118934109] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Desorption electrospray ionization (DESI) coupled to high-resolution Orbitrap mass spectrometry (MS) was used to study the reactivity of a (β-amino alcohol)(arene)RuCl transfer hydrogenation catalytic precursor in methanol (CH(3)OH). By placing [(p-cymene)RuCl(2)](2) on a surface and spraying a solution of β-amino alcohol in methanol, two unique transient intermediates having lifetimes in the submillisecond to millisecond range were detected. These intermediates were identified as Ru (II) and Ru (IV) complexes incorporating methyl formate (HCOOCH(3)). The Ru (IV) intermediate is not observed when the DESI spray solution is sparged with Ar gas, indicating that O(2) dissolved in the solvent is necessary for oxidizing Ru (II) to Ru (IV). These proposed intermediates are supported by high-resolution and high mass accuracy measurements and by comparing experimental to calculated isotope profiles. Additionally, analyzing the bulk reaction mixture using gas chromatography-MS and nuclear magnetic resonance spectroscopy confirms the formation of HCOOCH(3). These results represent an example that species generated from the (β-amino alcohol)(arene)RuCl (II) catalytic precursor can selectively oxidize CH(3)OH to HCOOCH(3). This observation leads us to propose a pathway that can compete with the hydrogen transfer catalytic cycle. Although bifunctional hydrogen transfer with Ru catalysts has been well-studied, the ability of DESI to intercept intermediates formed in the first few milliseconds of a chemical reaction allowed identification of previously unrecognized intermediates and reaction pathways in this catalytic system.
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35
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Hamdy OM, Julian RR. Reflections on charge state distributions, protein structure, and the mystical mechanism of electrospray ionization. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2012; 23:1-6. [PMID: 22076632 DOI: 10.1007/s13361-011-0284-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Revised: 10/18/2011] [Accepted: 10/19/2011] [Indexed: 05/31/2023]
Abstract
The connection between charge state distributions, protein structure, and mechanistic details of electrospray are discussed in relation to the emerging field of gas phase structural biology. Comparisons are drawn with the established area of enzymatic catalysis in organic solvents, which shares many similar challenges. Charge solvation emerges as a dominant force in both systems that must be dealt with to enable kinetic trapping of native structures in foreign environments. Potential methods for mediating unfavorable charge solvation effects are discussed and, ironically, do not include partial solvation by water. The importance of timescale in relation to the evolution of protein structure during the process of electrospray ionization is discussed. Finally several prospects for future endeavors are highlighted.
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36
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Ferguson CN, Benchaar SA, Miao Z, Loo JA, Chen H. Direct ionization of large proteins and protein complexes by desorption electrospray ionization-mass spectrometry. Anal Chem 2011; 83:6468-73. [PMID: 21774530 DOI: 10.1021/ac201390w] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Desorption electrospray ionization-mass spectrometry (DESI-MS) has advantages for rapid sample analysis with little or no sample pretreatment, but performance for large biomolecules has not been demonstrated. In this study, liquid sample DESI, an extended version of DESI used for analysis of liquid samples, was shown to have capabilities for direct ionization of large noncovalent protein complexes (>45 kDa) and proteins (up to 150 kDa). Protein complex ions (e.g., superoxide dismutase, enolase, and hemoglobin) desorbed from solution by liquid sample DESI were measured intact, indicating the capability of DESI for preserving weak noncovalent interactions. Doping the DESI spray solvent with supercharging reagents resulted in protein complex ions having increased multiple charging without complex dissociation. Ion mobility measurements of model protein cytochrome c showed that the supercharging reagent favored the more compact conformation for the lower charged protein ions. Liquid sample DESI of hydrophobic peptide gramicidin D suggests that the ionization mechanism involves a droplet pick-up mixing process. Measurement of liquid samples significantly extends the mass range of DESI-MS, allowing the analysis of high-mass proteins such as 150 kDa immunoglobulin G (IgG) and thus represents the largest protein successfully ionized by DESI to date.
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Affiliation(s)
- Carly N Ferguson
- Department of Chemistry and Biochemistry, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, California 90095, USA
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Campbell IS, Ton AT, Mulligan CC. Direct detection of pharmaceuticals and personal care products from aqueous samples with thermally-assisted desorption electrospray ionization mass spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2011; 22:1285-1293. [PMID: 21953111 DOI: 10.1007/s13361-011-0144-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2011] [Revised: 03/24/2011] [Accepted: 03/27/2011] [Indexed: 05/31/2023]
Abstract
An ambient mass spectrometric method based on desorption electrospray ionization (DESI) has been developed to allow rapid, direct analysis of contaminated water samples, and the technique was evaluated through analysis of a wide array of pharmaceutical and personal care product (PPCP) contaminants. Incorporating direct infusion of aqueous sample and thermal assistance into the source design has allowed low ppt detection limits for the target analytes in drinking water matrices. With this methodology, mass spectral information can be collected in less than 1 min, consuming ~100 μL of total sample. Quantitative ability was also demonstrated without the use of an internal standard, yielding decent linearity and reproducibility. Initial results suggest that this source configuration is resistant to carryover effects and robust towards multi-component samples. The rapid, continuous analysis afforded by this method offers advantages in terms of sample analysis time and throughput over traditional hyphenated mass spectrometric techniques.
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Affiliation(s)
- Ian S Campbell
- Department of Chemistry, Illinois State University, Normal, IL 61790, USA
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Miao Z, Chen H, Liu P, Liu Y. Development of Submillisecond Time-Resolved Mass Spectrometry Using Desorption Electrospray Ionization. Anal Chem 2011; 83:3994-7. [DOI: 10.1021/ac200842e] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Zhixin Miao
- Department of Chemistry and Biochemistry, Center for Intelligent Chemical Instrumentation, Ohio University, Athens, Ohio 45701, United States
| | - Hao Chen
- Department of Chemistry and Biochemistry, Center for Intelligent Chemical Instrumentation, Ohio University, Athens, Ohio 45701, United States
| | - Pengyuan Liu
- Department of Chemistry and Biochemistry, Center for Intelligent Chemical Instrumentation, Ohio University, Athens, Ohio 45701, United States
| | - Yan Liu
- Department of Chemistry and Biochemistry, Center for Intelligent Chemical Instrumentation, Ohio University, Athens, Ohio 45701, United States
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Zhang Y, Dewald HD, Chen H. Online Mass Spectrometric Analysis of Proteins/Peptides Following Electrolytic Cleavage of Disulfide Bonds. J Proteome Res 2011; 10:1293-304. [DOI: 10.1021/pr101053q] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yun Zhang
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, United States
| | - Howard D. Dewald
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, United States
| | - Hao Chen
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, United States
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Xu G, Chen B, Guo B, He D, Yao S. Detection of intermediates for the Eschweiler–Clarke reaction by liquid-phase reactive desorption electrospray ionization mass spectrometry. Analyst 2011; 136:2385-90. [DOI: 10.1039/c0an00879f] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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