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Jarrold MF. Single-Ion Mass Spectrometry for Heterogeneous and High Molecular Weight Samples. J Am Chem Soc 2024; 146:5749-5758. [PMID: 38394699 DOI: 10.1021/jacs.3c08139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2024]
Abstract
In charge detection mass spectrometry (CD-MS) the mass of each individual ion is determined from the measurement of its mass to charge ratio (m/z) and charge. Performing this measurement for thousands of ions allows mass distributions to be measured for heterogeneous and high mass samples that cannot be analyzed by conventional mass spectrometry (MS). CD-MS opens the door to accurate mass measurements for samples into the giga-Dalton regime, vastly expanding the reach of MS and allowing mass distributions to be determined for viruses, gene therapies, and vaccines. Following the success of CD-MS, single-ion mass measurements have recently been performed on an Orbitrap. CD-MS and Orbitrap individual ion mass spectrometry (I2MS) are described. Illustrative examples are provided, and the prospects for higher resolution measurements discussed. In the case of CD-MS, computer simulations indicate that much higher resolving powers are within reach. The ability to perform high-resolution CD-MS analysis of heterogeneous samples will be enabling and disruptive in top-down MS as high-resolution m/z and accurate charge measurements will allow very complex m/z spectra to be unraveled.
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Affiliation(s)
- Martin F Jarrold
- Chemistry Department, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47401, United States
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2
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Lai YH, Wang YS. Advances in high-resolution mass spectrometry techniques for analysis of high mass-to-charge ions. MASS SPECTROMETRY REVIEWS 2023; 42:2426-2445. [PMID: 35686331 DOI: 10.1002/mas.21790] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 01/27/2022] [Accepted: 04/07/2022] [Indexed: 06/15/2023]
Abstract
A major challenge in modern mass spectrometry (MS) is achieving high mass resolving power and accuracy for precision analyses in high mass-to-charge (m/z) regions. To advance the capability of MS for increasingly demanding applications, understanding limitations of state-of-the-art techniques and their status in applied sciences is essential. This review summarizes important instruments in high-resolution mass spectrometry (HRMS) and related advances to extend their working range to high m/z regions. It starts with an overview of HRMS techniques that provide adequate performance for macromolecular analysis, including Fourier-transform, time-of-flight (TOF), quadrupole-TOF, and related data-processing techniques. Methodologies and applications of HRMS for characterizing macromolecules in biochemistry and material sciences are summarized, such as top-down proteomics, native MS, drug discovery, structural virology, and polymer analyses.
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Affiliation(s)
- Yin-Hung Lai
- Genomics Research Center, Academia Sinica, Taipei, Taiwan, R.O.C
- Department of Chemical Engineering, National United University, Miaoli, Taiwan, R.O.C
- Institute of Food Safety and Health Risk Assessment, National Yang Ming Chiao Tung University, Taipei, Taiwan, R.O.C
| | - Yi-Sheng Wang
- Genomics Research Center, Academia Sinica, Taipei, Taiwan, R.O.C
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3
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Abstract
Charge detection mass spectrometry (CDMS) is a single-particle technique where the masses of individual ions are determined from simultaneous measurement of their mass-to-charge ratio (m/z) and charge. Masses are determined for thousands of individual ions, and then the results are binned to give a mass spectrum. Using this approach, accurate mass distributions can be measured for heterogeneous and high-molecular-weight samples that are usually not amenable to analysis by conventional mass spectrometry. Recent applications include heavily glycosylated proteins, protein complexes, protein aggregates such as amyloid fibers, infectious viruses, gene therapies, vaccines, and vesicles such as exosomes.
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Affiliation(s)
- Martin F Jarrold
- Chemistry Department, Indiana University, 800 E. Kirkwood Avenue, Bloomington, Indiana 47404, United States
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4
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Jiang LX, Plath LD, Halim MA, Friedrich S, Bier ME. Anatomy of Protein Electrospray Ionization Mass Spectra by Superconducting Tunnel Junction Mass and Energy Spectrometry. Anal Chem 2022; 94:5284-5292. [PMID: 35315644 DOI: 10.1021/acs.analchem.1c05074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cryogenic superconducting tunnel junction (STJ) detectors have the advantage of single-particle sensitivity, high quantum efficiency, low noise, and the ability to detect the time and relative impact energy of deposited ions. This makes them attractive for use in mass spectrometry (MS) and as a form of energy spectrometry. STJ cryodetectors have been coupled to time-of-flight (TOF) mass spectrometers equipped with a matrix-assisted laser desorption ionization (MALDI) source and to an electrospray ionization (ESI) TOF mass spectrometer. Here, a lab-made linear quadrupole ion trap (LIT) mass spectrometer system was coupled to an ESI source and a 16-channel Nb-STJ array with improved readout electronics. The goal was to investigate fundamentals of ESI-generated protein ions by further exploiting the advantage of resolving these ions in a third dimension of the relative energy deposited into the STJs. The proteins equine cytochrome c, bovine carbonic anhydrase, bovine serum albumin, and murine immunoglobulin G were studied using this ESI-LIT-STJ-MS instrument. Multiply charged monomers, multimers, and fragments from metastable ions were resolved from monomer peaks by differences in ion deposition energy even when these ions have the same mass-to-charge ratio as the corresponding monomer. The determination of a fragment mass from metastable decomposition is accomplished without knowing the charge state of the fragment. The average charge state of the multimers is reduced with each addition of a protein which is presumed to be a direct reflection of the surface area available for charging. Multiply charged in-source fragments have also been observed and distinguished in the mass spectrum of carbonic anhydrase by using the differences in the energy deposited in the STJs.
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Affiliation(s)
- Li-Xue Jiang
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213-2683, United States
| | - Logan D Plath
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213-2683, United States
| | - Mohammad A Halim
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213-2683, United States
| | - Stephan Friedrich
- Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Mark E Bier
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213-2683, United States
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5
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Brais CJ, Ibañez JO, Schwartz AJ, Ray SJ. RECENT ADVANCES IN INSTRUMENTAL APPROACHES TO TIME-OF-FLIGHT MASS SPECTROMETRY. MASS SPECTROMETRY REVIEWS 2021; 40:647-669. [PMID: 32779281 DOI: 10.1002/mas.21650] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 02/25/2020] [Accepted: 07/07/2020] [Indexed: 06/11/2023]
Abstract
Time-of-flight mass spectrometry (TOFMS) is one of the simplest and most powerful approaches for mass spectrometry. Realization of the advantages inherent in TOFMS requires innovation in the theory and practice of the technique. Instrumental developments, in turn, create new capabilities that enable applications in chemical measurement. This review focuses on the recent advances in TOFMS instrumentation. New strategies for ion acceleration, multiplexed detection, miniaturized TOFMS instruments, approaches to extend the length of ion flight, and novel ion detection technologies are reviewed. Techniques that change the basic paradigm of TOFMS by measuring m/z based on ion flight distance are considered, as are applications at the frontiers of instrumental performance. © 2020 John Wiley & Sons Ltd. Mass Spec Rev.
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Affiliation(s)
- Christopher J Brais
- Department of Chemistry, University at Buffalo, Buffalo, New York, 14260, USA
| | | | | | - Steven J Ray
- Department of Chemistry, University at Buffalo, Buffalo, New York, 14260, USA
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6
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Poindron A, Pedregosa-Gutierrez J, Jouvet C, Knoop M, Champenois C. Non-destructive detection of large molecules without mass limitation. J Chem Phys 2021; 154:184203. [PMID: 34241003 DOI: 10.1063/5.0046693] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The problem for molecular identification knows many solutions, which include mass spectrometers whose mass sensitivity depends on the performance of the detector involved. The purpose of this article is to show by means of molecular dynamics simulations how a laser-cooled ion cloud, confined in a linear radio-frequency trap, can reach the ultimate sensitivity providing the detection of individual charged heavy molecular ions. In our simulations, we model the laser-cooled Ca+ ions as two-level atoms, confined thanks to a set of constant and time oscillating electrical fields. A singly charged molecular ion with a mass of 106 amu is propelled through the ion cloud. The induced change in the fluorescence rate of the latter is used as the detection signal. We show that this signal is due to a significant temperature variation triggered by the Coulomb repulsion and amplified by the radio-frequency heating induced by the trap itself. We identify the optimum initial energy for the molecular ion to be detected, and furthermore, we characterize the performance of the detector for a large range of confinement voltages.
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Affiliation(s)
- A Poindron
- Aix Marseille University, CNRS, PIIM, Marseille, France
| | | | - C Jouvet
- Aix Marseille University, CNRS, PIIM, Marseille, France
| | - M Knoop
- Aix Marseille University, CNRS, PIIM, Marseille, France
| | - C Champenois
- Aix Marseille University, CNRS, PIIM, Marseille, France
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7
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Todd AR, Barnes LF, Young K, Zlotnick A, Jarrold MF. Higher Resolution Charge Detection Mass Spectrometry. Anal Chem 2020; 92:11357-11364. [PMID: 32806905 PMCID: PMC8587657 DOI: 10.1021/acs.analchem.0c02133] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Charge detection mass spectrometry is a single particle technique where the masses of individual ions are determined from simultaneous measurements of each ion's m/z ratio and charge. The ions pass through a conducting cylinder, and the charge induced on the cylinder is detected. The cylinder is usually placed inside an electrostatic linear ion trap so that the ions oscillate back and forth through the cylinder. The resulting time domain signal is analyzed by fast Fourier transformation; the oscillation frequency yields the m/z, and the charge is determined from the magnitudes. The mass resolving power depends on the uncertainties in both quantities. In previous work, the mass resolving power was modest, around 30-40. In this work we report around an order of magnitude improvement. The improvement was achieved by coupling high-accuracy charge measurements (obtained with dynamic calibration) with higher resolution m/z measurements. The performance was benchmarked by monitoring the assembly of the hepatitis B virus (HBV) capsid. The HBV capsid assembly reaction can result in a heterogeneous mixture of intermediates extending from the capsid protein dimer to the icosahedral T = 4 capsid with 120 dimers. Intermediates of all possible sizes were resolved, as well as some overgrown species. Despite the improved mass resolving power, the measured peak widths are still dominated by instrumental resolution. Heterogeneity makes only a small contribution. Resonances were observed in some of the m/z spectra. They result from ions with different masses and charges having similar m/z values. Analogous resonances are expected whenever the sample is a heterogeneous mixture assembled from a common building block.
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8
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Todd AR, Alexander AW, Jarrold MF. Implementation of a Charge-Sensitive Amplifier without a Feedback Resistor for Charge Detection Mass Spectrometry Reduces Noise and Enables Detection of Individual Ions Carrying a Single Charge. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2020; 31:146-154. [PMID: 32881508 DOI: 10.1021/jasms.9b00010] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Charge detection mass spectrometry (CDMS) depends on the measurement of the charge induced on a cylinder by individual ions by means of a charge-sensitive amplifier. Electrical noise limits the accuracy of the charge measurement and the smallest charge that can be detected. Thermal noise in the feedback resistor is a major source of electrical noise. We describe the implementation of a charge-sensitive amplifier without a feedback resistor. The design has significantly reduced 1/f noise facilitating the detection of high m/z ions and substantially reducing the measurement time required to achieve almost perfect charge accuracy. With the new design we have been able to detect individual ions carrying a single charge. This is an important milestone in the development of CDMS.
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Affiliation(s)
- Aaron R Todd
- Chemistry Department, Indiana University, Bloomington, Indiana 47405, United States
| | - Andrew W Alexander
- Chemistry Department, Indiana University, Bloomington, Indiana 47405, United States
| | - Martin F Jarrold
- Chemistry Department, Indiana University, Bloomington, Indiana 47405, United States
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9
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Tang Y, Xu Q, Li D, Xu W. A mini mass spectrometer with a low noise Faraday detector. Analyst 2020; 145:3892-3898. [DOI: 10.1039/d0an00420k] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A low noise Faraday detector and a data processing method were developed for a miniature ion trap mass spectrometer.
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Affiliation(s)
- Yang Tang
- School of Life Science
- Beijing Institute of Technology
- Beijing 100081
- China
| | - Qian Xu
- School of Life Science
- Beijing Institute of Technology
- Beijing 100081
- China
| | - Dayu Li
- School of Computer Science and Engineering
- Northeastern University
- Shenyang 110819
- China
| | - Wei Xu
- School of Life Science
- Beijing Institute of Technology
- Beijing 100081
- China
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10
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Todd AR, Jarrold MF. Dramatic Improvement in Sensitivity with Pulsed Mode Charge Detection Mass Spectrometry. Anal Chem 2019; 91:14002-14008. [PMID: 31589418 PMCID: PMC6834878 DOI: 10.1021/acs.analchem.9b03586] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Charge detection mass spectrometry (CDMS) is emerging as a valuable tool to determine mass distributions for heterogeneous and high-mass samples. It is a single-particle technique where masses are determined for individual ions from simultaneous measurements of their mass-to-charge ratio (m/z) and charge. Ions are trapped in an electrostatic linear ion trap (ELIT) and oscillate back and forth through a detection cylinder. The trap is open and able to trap ions for a small fraction of the total measurement time so most of the ions (>99.8%) in a continuous ion beam are lost. Here, we implement an ion storage scheme where ions are accumulated and stored in a hexapole and then injected into the ELIT at the right time for them to be trapped. This pulsed mode of operation increases the sensitivity of CDMS by more than 2 orders of magnitude, which allows much lower titer samples to be analyzed. A limit of detection of 3.3 × 108 particles/mL was obtained for hepatitis B virus T = 4 capsids with a 1.3 μL sample. The hexapole where the ions are accumulated and stored is a significant distance from the ion trap so ions are dispersed in time by their m/z values as they travel between the hexapole and the ELIT. By varying the delay time between ion release and trapping, different windows of m/z values can be trapped.
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Affiliation(s)
- Aaron R. Todd
- Chemistry Department, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Martin F. Jarrold
- Chemistry Department, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
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11
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Hogan JA, Jarrold MF. Optimized Electrostatic Linear Ion Trap for Charge Detection Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:2086-2095. [PMID: 29987663 DOI: 10.1007/s13361-018-2007-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 05/25/2018] [Accepted: 05/29/2018] [Indexed: 06/08/2023]
Abstract
In charge detection mass spectrometry (CDMS), ions are passed through a detection tube and the m/z ratio and charge are determined for each ion. The uncertainty in the charge and m/z determinations can be dramatically reduced by embedding the detection tube in an electrostatic linear ion trap (ELIT) so that ions oscillate back and forth through the detection tube. The resulting time domain signal can be analyzed by fast Fourier transforms (FFTs). The ion's m/z is proportional to the square of the oscillation frequency, and its charge is derived from the FFT magnitude. The ion oscillation frequency is dependent on the physical dimensions of the trap as well as the ion energy. A new ELIT has been designed for CDMS using the central particle method. In the new design, the kinetic energy dependence of the ion oscillation frequency is reduced by an order of magnitude. An order of magnitude reduction in energy dependence should have led to an order of magnitude reduction in the uncertainty of the m/z determination. In practice, a factor of four improvements was achieved. This discrepancy is probably mainly due to the trajectory dependence of the ion oscillation frequency. The new ELIT design uses a duty cycle of 50%. We show that a 50% duty cycle produces the lowest uncertainty in the charge determination. This is due to the absence of even-numbered harmonics in the FFT, which in turn leads to an increase in the magnitude of the peak at the fundamental frequency. Graphical Abstract ᅟ.
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Affiliation(s)
- Joanna A Hogan
- Chemistry Department, Indiana University, Bloomington, IN, 47405, USA
| | - Martin F Jarrold
- Chemistry Department, Indiana University, Bloomington, IN, 47405, USA.
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12
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Keifer DZ, Jarrold MF. Single-molecule mass spectrometry. MASS SPECTROMETRY REVIEWS 2017; 36:715-733. [PMID: 26873676 DOI: 10.1002/mas.21495] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 01/15/2016] [Indexed: 06/05/2023]
Abstract
In single-molecule mass spectrometry, the mass of each ion is measured individually; making it suitable for the analysis of very large, heterogeneous objects that cannot be analyzed by conventional means. A range of single-molecule mass spectrometry techniques has been developed, including time-of-flight with cryogenic detectors, a quadrupole ion trap with optical detection, single-molecule Fourier transform ion cyclotron resonance, charge detection mass spectrometry, quadrupole ion traps coupled to charge detector plates, and nanomechanical oscillators. In addition to providing information on mass and heterogeneity, these techniques have been used to study impact craters from cosmic dust, monitor the assembly of viruses, elucidate the fluorescence dynamics of quantum dots, and much more. This review focuses on the merits of each of these technologies, their limitations, and their applications. © 2016 Wiley Periodicals, Inc. Mass Spec Rev 36:715-733, 2017.
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Affiliation(s)
- David Z Keifer
- Department of Chemistry, Indiana University, 800 E. Kirkwood Ave., Bloomington, IN, 47401
| | - Martin F Jarrold
- Department of Chemistry, Indiana University, 800 E. Kirkwood Ave., Bloomington, IN, 47401
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13
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Keifer DZ, Pierson EE, Jarrold MF. Charge detection mass spectrometry: weighing heavier things. Analyst 2017; 142:1654-1671. [DOI: 10.1039/c7an00277g] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Charge detection mass spectrometry (CDMS) is a single molecule method where the mass of each ion is directly determined from individual measurements of its mass-to-charge ratio and charge.
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Affiliation(s)
| | - Elizabeth E. Pierson
- Department of Analytical Sciences
- Pharmaceutical Sciences and Clinical Supplies
- Merck Research Laboratories
- Merck & Co
- Inc
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14
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Keifer DZ, Motwani T, Teschke CM, Jarrold MF. Acquiring Structural Information on Virus Particles with Charge Detection Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2016; 27:1028-36. [PMID: 27020925 PMCID: PMC5095694 DOI: 10.1007/s13361-016-1362-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 02/04/2016] [Accepted: 02/06/2016] [Indexed: 05/10/2023]
Abstract
Charge detection mass spectrometry (CDMS) is a single-molecule technique particularly well-suited to measuring the mass and charge distributions of heterogeneous, MDa-sized ions. In this work, CDMS has been used to analyze the assembly products of two coat protein variants of bacteriophage P22. The assembly products show broad mass distributions extending from 5 to 15 MDa for A285Y and 5 to 25 MDa for A285T coat protein variants. Because the charge of large ions generated by electrospray ionization depends on their size, the charge can be used to distinguish hollow shells from more compact structures. A285T was found to form T = 4 and T = 7 procapsids, and A285Y makes a small number of T = 3 and T = 4 procapsids. Owing to the decreased stability of the A285Y and A285T particles, chemical cross-linking was required to stabilize them for electrospray CDMS.Graphical Abstract.
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Affiliation(s)
- David Z Keifer
- Department of Chemistry, Indiana University, Bloomington, IN, 47405, USA
| | - Tina Motwani
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, 06269, USA
| | - Carolyn M Teschke
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, 06269, USA
- Department of Chemistry, University of Connecticut, Storrs, CT, 06269, USA
| | - Martin F Jarrold
- Department of Chemistry, Indiana University, Bloomington, IN, 47405, USA.
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15
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Peng WP, Chou SW, Patil AA. Measuring masses of large biomolecules and bioparticles using mass spectrometric techniques. Analyst 2014; 139:3507-23. [DOI: 10.1039/c3an02329j] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Mass spectrometric techniques can measure the masses and fragments of large biomolecules and bioparticles.
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Affiliation(s)
- Wen-Ping Peng
- Department of Physics
- National Dong Hwa University
- Hualien, Republic of China
| | - Szu-Wei Chou
- Department of Physics
- National Dong Hwa University
- Hualien, Republic of China
| | - Avinash A. Patil
- Department of Physics
- National Dong Hwa University
- Hualien, Republic of China
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16
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Weidmann S, Mikutis G, Barylyuk K, Zenobi R. Mass discrimination in high-mass MALDI-MS. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2013; 24:1396-1404. [PMID: 23836380 DOI: 10.1007/s13361-013-0686-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 05/27/2013] [Accepted: 05/28/2013] [Indexed: 06/02/2023]
Abstract
In high-mass matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), the accessible m/z range is limited by the detector used. Therefore, special high-mass detectors based on ion conversion dynodes (ICDs) have been developed. Recently, we have found that mass bias may exist when such ICD detectors are used [Weidmann et al., Anal. Chem. 85(6), 3425-3432 (2013)]. In this contribution, the mass-dependent response of an ICD detector was systematically studied, the response factors for proteins with molecular weights from 35.9 to 129.9 kDa were determined, and the reasons for mass bias were identified. Compared with commonly employed microchannel plate detectors, we found that the mass discrimination is less pronounced, although ions with higher masses are weakly favored when using an ICD detector. The relative response was found to depend on the laser power used for MALDI; low-mass ions are discriminated against with higher laser power. The effect of mutual ion suppression in dependence of the proteins used and their molar ratio is shown. Mixtures consisting of protein oligomers that only differ in mass show less mass discrimination than mixtures consisting of different proteins with similar masses. Furthermore, mass discrimination increases for molar ratios far from 1. Finally, we present clear guidelines that help to choose the experimental parameters such that the response measured matches the actual molar fraction as closely as possible.
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Affiliation(s)
- Simon Weidmann
- Department of Chemistry and Applied Biosciences, ETH (Swiss Federal Institute of Technology) Zürich, Zürich, Switzerland
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17
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Park J, Aksamija Z, Shin HC, Kim H, Blick RH. Phonon-assisted field emission in silicon nanomembranes for time-of-flight mass spectrometry of proteins. NANO LETTERS 2013; 13:2698-2703. [PMID: 23621694 DOI: 10.1021/nl400873m] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Time-of-flight (TOF) mass spectrometry has been considered as the method of choice for mass analysis of large intact biomolecules, which are ionized in low charge states by matrix-assisted-laser-desorption/ionization (MALDI). However, it remains predominantly restricted to the mass analysis of biomolecules with a mass below about 50,000 Da. This limitation mainly stems from the fact that the sensitivity of the standard detectors decreases with increasing ion mass. We describe here a new principle for ion detection in TOF mass spectrometry, which is based upon suspended silicon nanomembranes. Impinging ion packets on one side of the suspended silicon nanomembrane generate nonequilibrium phonons, which propagate quasi-diffusively and deliver thermal energy to electrons within the silicon nanomembrane. This enhances electron emission from the nanomembrane surface with an electric field applied to it. The nonequilibrium phonon-assisted field emission in the suspended nanomembrane connected to an effective cooling of the nanomembrane via field emission allows mass analysis of megadalton ions with high mass resolution at room temperature. The high resolution of the detector will give better insight into high mass proteins and their functions.
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Affiliation(s)
- Jonghoo Park
- Department of Electrical Engineering, Kyungpook National University, Daegu, Korea
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18
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Jungmann JH, Heeren RMA. Detection systems for mass spectrometry imaging: a perspective on novel developments with a focus on active pixel detectors. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2013; 27:1-23. [PMID: 23239313 DOI: 10.1002/rcm.6418] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 09/21/2012] [Accepted: 09/23/2012] [Indexed: 05/18/2023]
Abstract
Instrumental developments for imaging and individual particle detection for biomolecular mass spectrometry (imaging) and fundamental atomic and molecular physics studies are reviewed. Ion-counting detectors, array detection systems and high mass detectors for mass spectrometry (imaging) are treated. State-of-the-art detection systems for multi-dimensional ion, electron and photon detection are highlighted. Their application and performance in three different imaging modes--integrated, selected and spectral image detection--are described. Electro-optical and microchannel-plate-based systems are contrasted. The analytical capabilities of solid-state pixel detectors--both charge coupled device (CCD) and complementary metal oxide semiconductor (CMOS) chips--are introduced. The Medipix/Timepix detector family is described as an example of a CMOS hybrid active pixel sensor. Alternative imaging methods for particle detection and their potential for future applications are investigated.
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Affiliation(s)
- Julia H Jungmann
- FOM Institute AMOLF, Science Park 104, 1098 XG, Amsterdam, The Netherlands
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Sclafani M, Marksteiner M, Keir FM, Divochiy A, Korneev A, Semenov A, Gol'tsman G, Arndt M. Sensitivity of a superconducting nanowire detector for single ions at low energy. NANOTECHNOLOGY 2012; 23:065501. [PMID: 22248823 DOI: 10.1088/0957-4484/23/6/065501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report on the characterization of a superconducting nanowire detector for ions at low kinetic energies. We measure the absolute single-particle detection efficiency η and trace its increase with energy up to η = 100%. We discuss the influence of noble gas adsorbates on the cryogenic surface and analyze their relevance for the detection of slow massive particles. We apply a recent model for the hot-spot formation to the incidence of atomic ions at energies between 0.2 and 1 keV. We suggest how the differences observed for photons and atoms or molecules can be related to the surface condition of the detector and we propose that the restoration of proper surface conditions may open a new avenue for SSPD-based optical spectroscopy on molecules and nanoparticles.
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Affiliation(s)
- Michele Sclafani
- Vienna Center for Quantum Science and Technology, Faculty of Physics, University of Vienna, Vienna, Austria
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20
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Affiliation(s)
- Feng Xian
- Department
of Chemistry and
Biochemistry, Florida State University,
95 Chieftain Way, Tallahassee, Florida 32310-4390, United States
| | - Christopher L. Hendrickson
- Department
of Chemistry and
Biochemistry, Florida State University,
95 Chieftain Way, Tallahassee, Florida 32310-4390, United States
- Ion Cyclotron Resonance Program, National High Magnetic Field Laboratory, 1800
East Paul Dirac Drive, Tallahassee, Florida 32310-4005, United States
| | - Alan G. Marshall
- Department
of Chemistry and
Biochemistry, Florida State University,
95 Chieftain Way, Tallahassee, Florida 32310-4390, United States
- Ion Cyclotron Resonance Program, National High Magnetic Field Laboratory, 1800
East Paul Dirac Drive, Tallahassee, Florida 32310-4005, United States
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21
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Mädler S, Boeri Erba E, Zenobi R. MALDI-ToF mass spectrometry for studying noncovalent complexes of biomolecules. Top Curr Chem (Cham) 2012; 331:1-36. [PMID: 22371170 DOI: 10.1007/128_2011_311] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) has been demonstrated to be a valuable tool to investigate noncovalent interactions of biomolecules. The direct detection of noncovalent assemblies is often more troublesome than with electrospray ionization. Using dedicated sample preparation techniques and carefully optimized instrumental parameters, a number of biomolecule assemblies were successfully analyzed. For complexes dissociating under MALDI conditions, covalent stabilization with chemical cross-linking is a suitable alternative. Indirect methods allow the detection of noncovalent assemblies by monitoring the fading of binding partners or altered H/D exchange patterns.
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Affiliation(s)
- Stefanie Mädler
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8093, Zurich, Switzerland
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22
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Park J, Qin H, Scalf M, Hilger RT, Westphall MS, Smith LM, Blick RH. A mechanical nanomembrane detector for time-of-flight mass spectrometry. NANO LETTERS 2011; 11:3681-3684. [PMID: 21806063 DOI: 10.1021/nl201645u] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We describe here a new principle for ion detection in time-of-flight (TOF) mass spectrometry in which an impinging ion packet excites mechanical vibrations in a silicon nitride (Si(3)N(4)) nanomembrane. The nanomembrane oscillations are detected by means of time-varying field emission of electrons from the mechanically oscillating nanomembrane. Ion detection is demonstrated in the MALDI-TOF analysis of proteins varying in mass from 5729 (insulin) to 150,000 (Immunoglobulin G) daltons. The detector response agrees well with the predictions of a thermomechanical model in which the impinging ion packet causes a nonuniform temperature distribution in the nanomembrane, exciting both fundamental and higher order oscillations.
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Affiliation(s)
- Jonghoo Park
- Electrical and Computer Engineering, University of Wisconsin, Madison, Wisconsin 53706, United States
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23
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Doussineau T, Bao CY, Clavier C, Dagany X, Kerleroux M, Antoine R, Dugourd P. Infrared multiphoton dissociation tandem charge detection-mass spectrometry of single megadalton electrosprayed ions. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2011; 82:084104. [PMID: 21895258 DOI: 10.1063/1.3628667] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
This work presents the implementation of tandem mass spectrometry for experiments on single electrosprayed ions from compounds of megadalton (MDa) molecular weight, using two charge detection devices. The first mass spectrometry stage (first charge detection device) combined with an ion gate allows both mass-to-charge ratio and charge selections of the megadalton ion of interest. The second stage is based on an electrostatic ion trap and consists of an image charge detection tube mounted between two ion mirrors. Single MDa ions can be stored for several dozen milliseconds. During the trapping time, single ions can be irradiated by a continuous wavelength CO(2) laser. We observe stepwise changes in the charge of a single trapped ion owing to multiphoton activation. Illustration of infrared multiphoton dissociation tandem mass spectrometry are given for single megadalton ions of poly(ethylene oxide)s and DNAs.
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24
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Erba EB, Zenobi R. Mass spectrometric studies of dissociation constants of noncovalent complexes. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c1pc90006d] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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25
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Suzuki K, Ohkubo M, Ukibe M, Chiba-Kamoshida K, Shiki S, Miki S, Wang Z. Charge-state-derivation ion detection using a super-conducting nanostructure device for mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2010; 24:3290-3296. [PMID: 20973003 DOI: 10.1002/rcm.4780] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Mass spectrometry (MS) is a method of analyzing ions based on their mass/charge (m/z) ratios. The m/z peak identification requires speculation on the ionic unit-charge states. This problem can be solved by using superconducting junction devices to measure the kinetic energies of single molecules. However, the kinetic energy measurement is followed by the dead time of 1-20 µs, which is fatally slow for modern high-resolution time-of-flight (TOF) analyzers. In this paper, we demonstrate that a superconducting nano-stripline detector (SSLD) composed of a 10-nm-thick and 800-nm-wide NbN strip realizes the charge-state derivation, and furthermore satisfies the ideal MS detector specifications such as a nano-second response, a short recovery time, a wide mass range, and no noise.
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Affiliation(s)
- K Suzuki
- Research Institute of Instrumentation Frontier, National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
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26
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Seyfried BK, Siekmann J, Belgacem O, Wenzel RJ, Turecek PL, Allmaier G. MALDI linear TOF mass spectrometry of PEGylated (glyco)proteins. JOURNAL OF MASS SPECTROMETRY : JMS 2010; 45:612-617. [PMID: 20527029 DOI: 10.1002/jms.1746] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
PEGylation of proteins is a fast growing field in biotechnology and pharmaceutical sciences owing to its ability to prolong the serum half-life time of recombinant proteins. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS) has been shown to be a powerful tool in the analysis of several PEGylated small proteins. Here we present data obtained with a standard secondary electron multiplier (SEM) and a high mass (HM) detector combined with a MALDI linear TOF MS system for the detection of PEGylated (glyco)proteins in the range of 60-600 kDa. Examples of MALDI TOF MS of small (interferon alpha2a), middle (human serum albumin (HSA)) and high molecular mass proteins (coagulation factor VIII and von Willebrand factor (vWF), both heavily glycosylated proteins) are presented. The particular challenge for the analysis was the heterogeneity of the (glyco)proteins in the high molecular weight range in combination with additional PEGylation, which even introduced more heterogeneity and was more challenging for interpretation. Nevertheless, the performance of MALDI linear TOF MS with both detector systems in terms molecular weight and heterogeneity determination depending on the m/z range was superior to the other methods. Although the SEM was able to obtain information about protein PEGylation in the mass range up to 100 kDa (e.g. PEGylated HSA), the HM system was crucial for detection of HM ions (e.g. PEGylated recombinant vWF), which was impossible with the standard SEM.
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Affiliation(s)
- Birgit K Seyfried
- Institute of Chemical Technologies and Analytics, Vienna University of Technology, Vienna, Austria
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27
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Chang HC. Ultrahigh-mass mass spectrometry of single biomolecules and bioparticles. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2009; 2:169-185. [PMID: 20636058 DOI: 10.1146/annurev-anchem-060908-155245] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Since the advent of soft ionization methods, mass spectrometry (MS) has found widespread application in the life sciences. Mass is now known to be a critical parameter for characterization of biomolecules and their complexes; it is also a useful parameter to characterize bioparticles such as viruses and cells. However, because of the genetic diversity of these entities, it is necessary to measure their masses individually and to obtain the corresponding mean masses and mass distributions. Here, I review recent technological developments that enable mass measurement of ultrahigh-mass biomolecules and bioparticles at the single-ion level. Some representative examples include cryodetection time-of-flight MS of single-megadalton protein ions, Millikan-type mass measurements of single viruses in a cylindrical ion trap, and charge-detection quadrupole ion trap MS of single whole cells. I also discuss the promises and challenges of these new technologies in real-world applications.
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Affiliation(s)
- Huan-Cheng Chang
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan.
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28
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Shiki S, Ukibe M, Sato Y, Tomita S, Hayakawa S, Ohkubo M. Kinetic-energy-sensitive mass spectrometry for separation of different ions with the same m/z value. JOURNAL OF MASS SPECTROMETRY : JMS 2008; 43:1686-1691. [PMID: 18698555 DOI: 10.1002/jms.1459] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A double-focusing mass spectrometer (MS) equipped with a superconducting-tunnel-junction (STJ) detector has been applied to measure relative ionization cross-sections for the production of ions that are accompanied by different ion species with the same mass-to-charge (m/z) value. The STJ detector fabricated for this study enables kinetic energy (E) measurement of incoming individual ions at a counting rate of up to approximately 100 k ions/s and an energy resolution (DeltaE/E) of 15%. Both high counting rate and high-energy resolution are necessary to independently determine both m and z and not the m/z value only in ion-counting MS experiments. Ions such as (14)N(2) (2+) and (14)N(+) with the same m/z value can be clearly discriminated using a kinetic-energy-sensitive MS. This fine discrimination capability allows direct determination of relative ionization cross-sections of the homonuclear diatomic ions (14)N(2) (2+)/(14)N(2) (+) and (16)O(2) (2+)/(16)O(2) (+), which are difficult to measure due to the strong interference by the signals of their dissociated atomic ions with noticeably large ionization cross-sections. The new instrument requires no low-abundance heteronuclear diatomic molecules of the forms (14)N(15)N or (16)O(17)O to carry out ionization studies and thus, is expected to be useful in fields such as atmospheric science, interstellar science, or plasma physics.
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Affiliation(s)
- Shigetomo Shiki
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8568, Japan
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29
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Aksenov AA, Bier ME. The analysis of polystyrene and polystyrene aggregates into the mega dalton mass range by cryodetection MALDI TOF MS. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2008; 19:219-230. [PMID: 18083529 DOI: 10.1016/j.jasms.2007.10.019] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2007] [Revised: 09/27/2007] [Accepted: 10/19/2007] [Indexed: 05/25/2023]
Abstract
Mass spectra of atactic polystyrene were collected into the mega-dalton mass range with a matrix-assisted laser desorption ionization time of flight (MALDI TOF) mass spectrometer, which incorporates a cryodetector comprised of an array of 16 superconducting tunnel junctions (STJ). The STJ cryodetector, theoretically, has no loss in signal response at any mass compared with the reduced signal found at high mass when using a conventional secondary-ionization detector. Since ion detection at high m/z is one of the fundamental limitations of mass spectrometry (MS), the cryodetector was used to explore the high m/z limit of the MALDI TOF technique for the analysis of two polymer types. Mass spectra were collected for polystyrene at Mn 170, 400, 900, and 2000 kDa and polymethyl methacrylate (PMMA) at Mn 62.6 kDa and 153.7 kDa. For polystyrene, the data showed a trend toward increased aggregation and charge state with mass. The Mn 2 MDa polystyrene data revealed a peak at m/z 2.2 MegaTh and a charge state analysis revealed that these ions were primarily polystyrene aggregates with a mass of approximately 4 MDa. This aggregate assignment was possible because the cryodetector response allows for the determination of a charge state up to about four. The contribution of each charge state for a selected peak can be determined in this fashion. This analysis revealed the preferential formation of doubly charged even-numbered aggregates over odd-numbered aggregates for high molecular mass polystyrene. A potential mechanism for the aggregation process for doubly charged species is discussed.
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Affiliation(s)
- Alexander A Aksenov
- Center for Molecular Analysis, Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213-2683, USA
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30
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Mabbett SR, Zilch LW, Maze JT, Smith JW, Jarrold MF. Pulsed acceleration charge detection mass spectrometry: application to weighing electrosprayed droplets. Anal Chem 2007; 79:8431-9. [PMID: 17929878 DOI: 10.1021/ac071513s] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We describe a new approach to measuring the masses of individual macroions. The method employs a pulsed acceleration tube located between two sensitive image charge detectors. The charge and velocity of the macroion are recorded with the first image charge detector. The ion is pulse accelerated through a known voltage drop, and then the charge and velocity are remeasured using the second image charge detector. The mass of the ion is deduced from its charge and its initial and final velocities. The approach has been used to measure masses in the 10(10)-10(14) Da range with z = 10(3)-10(6) and m/z = 10(6)-10(9). It should be extendable to masses of <10(6) Da. We have used the method to determine the size and charge of water droplets transmitted through a capillary interface and an aperture interface. The droplets detected from the aperture interface are approximately 1 order of magnitude smaller in mass than those detected from the capillary interface. The droplets from both interfaces have relatively low charges, particularly with the capillary interface where they are only charged to a small fraction of the Rayleigh limit. These results suggest that the aerodynamic breakup of the droplets plays a significant role in the mechanism of electrospray ionization.
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Affiliation(s)
- Sarah R Mabbett
- Chemistry Department, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, USA
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31
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Wenzel RJ, Matter U, Schultheis L, Zenobi R. Analysis of megadalton ions using cryodetection MALDI time-of-flight mass spectrometry. Anal Chem 2007; 77:4329-37. [PMID: 16013843 DOI: 10.1021/ac0482054] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Presented are initial results from the first commercially available matrix-assisted laser desorption/ionization time-of-flight mass spectrometer specifically designed for the sensitive detection of very high mass ions (macromizer, Comet AG). This new instrument utilizes a 16-element superconducting tunnel junction detector coupled with a fully adjustable gimbal-mounted ion source/focusing region that allows unparalleled sensitivity for detection of singly charged high molecular weight ions. Using this new technology, the singly charged ions in the megadalton region are detected from immunoglobulin M and von Willebrand factor proteins. This detector technology also measures the kinetic energy of the particles impacting the detector, which can be correlated to the charge of the particles. Immunoglobulin G and streptavidin were used to demonstrate the ability of the macromizer instrument to detect high-mass ions and to discern the charge state of the ions.
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Affiliation(s)
- Ryan J Wenzel
- Department of Chemistry, ETH Hönggerberg, CH-8093 Zürich, Switzerland, and Comet AG, CH-3175 Flamatt, Switzerland
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32
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Müller R, Allmaier G. Molecular weight determination of ultra-high mass compounds on a standard matrix-assisted laser desorption/ionization time-of-flight mass spectrometer: PAMAM dendrimer generation 10 and immunoglobulin M. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2006; 20:3803-6. [PMID: 17120275 DOI: 10.1002/rcm.2809] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
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33
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Peng WP, Cai Y, Chang HC. Optical detection methods for mass spectrometry of macroions. MASS SPECTROMETRY REVIEWS 2004; 23:443-465. [PMID: 15290710 DOI: 10.1002/mas.20002] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Detection of macroions has been a challenge in the field of mass spectrometry. Conventional ionization-based detectors, relying on production and multiplication of secondary electrons, are restricted to detection for charged particles of m/z < 1 x 10(6). While both energy-sensitive and charge-sensitive detectors have been developed recently to overcome the limitation, they are not yet in common use. Photon-sensitive detectors are suggested to be an alternative, with which detection of macroions (or charged particles) by either elastic light scattering (ELS) or laser-induced fluorescence (LIF) has been possible. In this article, we provide a critical review on the developments of novel optical detection methods for mass spectrometry of macroions, including both micron-sized and nano-sized synthetic polymers as well as high-mass biomolecules. Design and development of new spectrometers making possible observations of the mass spectra of macroions with sizes in the range of 10-10(3) nm or masses in the range of 1-10(6) MDa are illustrated. The potential and promise of this optical approach toward macroion detection with high efficiency are discussed in practical aspects.
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Affiliation(s)
- Wen-Ping Peng
- Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei, Taiwan 106
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34
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Cristoni S, Bernardi LR. Development of new methodologies for the mass spectrometry study of bioorganic macromolecules. MASS SPECTROMETRY REVIEWS 2003; 22:369-406. [PMID: 14528493 DOI: 10.1002/mas.10062] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In recent years, mass spectrometry has been increasingly used for the analysis of various macromolecules of biological, biomedical, and biochemical interest. This increase has been made possible by two key developments: the advent of electrospray ionization (ESI) and matrix-assisted laser desorption ionization (MALDI) sources. The two new techniques produce a significant increase in mass range and in sensitivity that led to the development of new applications and of new analyzer designs, software, and robotics. This review, apart from the description of the status of mass spectrometry in the analysis of bioorganic macromolecules, is mainly devoted to the illustration of the more recent promising techniques and on their possible future evolution.
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Affiliation(s)
- Simone Cristoni
- Università degli Studi di Milano, Centro Interdisciplinare Studi Bio-molecolari e Applicazioni Industriali CISI, Via Fratelli Cervi 93, 20090 Segrate Milano, Italy.
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35
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Cai Y, Peng WP, Chang HC. Ion trap mass spectrometry of fluorescently labeled nanoparticles. Anal Chem 2003; 75:1805-11. [PMID: 12713037 DOI: 10.1021/ac0206723] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mass spectra of fluorescently labeled polystyrene nanoparticles have been obtained using a combined technique of matrix-assisted laser desorption/ionization (MALDI), laser-induced fluorescence (LIF), and a dual quadrupole ion trap mass spectrometer. The spectrometer is designed in such a way that the first trap serves as a trapping and mass-analyzing device, while the second trap serves to capture and concentrate the ions ejected from the first trap for fluorescence detection. An enhancement in the LIF signal by more than 3 orders of magnitude is achieved with the help of the second trap, making mass/charge (m/z) analysis of the nanoparticles possible. Additional unique features of this mass spectrometer include that frequency scan (0.5-50 kHz) at a constant voltage (200 V), instead of voltage scan at a constant frequency, is implemented to widen the spectral analysis range of the instrument. The implementation has allowed the spectrometer to operate at relatively high buffer gas pressures (50 mTorr), crucial for effective trapping of the nanometer-sized particles generated by MALDI. We present in this report the first mass spectra of fluorescently labeled nanoparticles with a size of 27 nm using this new mass spectrometric approach. The utility of this method in the study of biological macromolecules or particles is demonstrated with dye-labeled IgG.
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Affiliation(s)
- Y Cai
- Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei, Taiwan 106
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36
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Current literature in mass spectrometry. JOURNAL OF MASS SPECTROMETRY : JMS 2001; 36:976-987. [PMID: 11523099 DOI: 10.1002/jms.95] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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37
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Rabin MW, Hilton GC, Martinis JM. Application of ion-impact energy measurement to electrospray ionization mass spectrometry of proteins and protein mixtures. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2001; 12:826-831. [PMID: 11444605 DOI: 10.1016/s1044-0305(01)00254-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We have used a normal metal-insulator-superconductor (NIS) microcalorimeter to measure the impact energy of protein ions produced by electrospray ionization (ESI) in a magnetic-sector mass spectrometer (MS). We have used these measurements to resolve spectral ambiguities and to analyze protein mixtures. Energy measurement may be useful for the direct MS analysis of complex biopolymer mixtures that normally would confound ESI-MS deconvolution algorithms.
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Affiliation(s)
- M W Rabin
- National Institute of Standards and Technology, Boulder, Colorado 80305-3328, USA.
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38
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Affiliation(s)
- J Godovac-Zimmermann
- Center for Molecular Medicine, Department of Medicine, University College London, 5 University Street, London WC1E 6JJ, United Kingdom.
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39
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Westmacott G, Frank M, Labov SE, Benner WH. Using a superconducting tunnel junction detector to measure the secondary electron emission efficiency for a microchannel plate detector bombarded by large molecular ions. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2000; 14:1854-1861. [PMID: 11006596 DOI: 10.1002/1097-0231(20001015)14:19%3c1854::aid-rcm102%3e3.0.co;2-m] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
An energy-sensitive superconducting tunnel junction (STJ) detector was used to measure the secondary electron emission efficiency, epsilon(e), for a microchannel plate (MCP) detector bombarded by large (up to 66 kDa), slow moving (<40 km/s) molecular ions. The method used is new and provides a more direct procedure for measuring the efficiency of secondary electron emission from a surface. Both detectors were exposed simultaneously to nearly identical ion fluxes. By exposing only a small area of the MCP detector to ions, such that the area exposed was effectively the same as the size of the STJ detector, the number of ions detected with each detector were directly comparable. The STJ detector is 100% efficient for detecting ions in the energy regime investigated and therefore it can be used to measure the detection efficiency and secondary electron emission efficiency of the MCP. The results are consistent with measurements made by other groups and provide further characterization of the loss in sensitivity noted previously when MCP detectors have been used to detect high-mass ions. Individual molecular ions of mass 66 kDa with 30 keV kinetic energy were measured to have about a 5% probability of producing one or more electrons when impacting the MCP. When ion energy was reduced to 10 keV, the detection probability decreased to 1 %. The secondary electron yield was calculated from the secondary electron emission efficiency and found to scale linearly with the mass of the impinging molecular ion and to about the fourth power of ion velocity. Secondary electrons were observed for primary ion impacts >5 km/s, regardless of mass, and no evidence of a velocity (detection) threshold was observed. Copyright 2000 John Wiley & Sons, Ltd.
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Affiliation(s)
- G Westmacott
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
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40
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Westmacott G, Frank M, Labov SE, Benner WH. Using a superconducting tunnel junction detector to measure the secondary electron emission efficiency for a microchannel plate detector bombarded by large molecular ions. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2000; 14:1854-1861. [PMID: 11006596 DOI: 10.1002/1097-0231(20001015)14:19<1854::aid-rcm102>3.0.co;2-m] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
An energy-sensitive superconducting tunnel junction (STJ) detector was used to measure the secondary electron emission efficiency, epsilon(e), for a microchannel plate (MCP) detector bombarded by large (up to 66 kDa), slow moving (<40 km/s) molecular ions. The method used is new and provides a more direct procedure for measuring the efficiency of secondary electron emission from a surface. Both detectors were exposed simultaneously to nearly identical ion fluxes. By exposing only a small area of the MCP detector to ions, such that the area exposed was effectively the same as the size of the STJ detector, the number of ions detected with each detector were directly comparable. The STJ detector is 100% efficient for detecting ions in the energy regime investigated and therefore it can be used to measure the detection efficiency and secondary electron emission efficiency of the MCP. The results are consistent with measurements made by other groups and provide further characterization of the loss in sensitivity noted previously when MCP detectors have been used to detect high-mass ions. Individual molecular ions of mass 66 kDa with 30 keV kinetic energy were measured to have about a 5% probability of producing one or more electrons when impacting the MCP. When ion energy was reduced to 10 keV, the detection probability decreased to 1 %. The secondary electron yield was calculated from the secondary electron emission efficiency and found to scale linearly with the mass of the impinging molecular ion and to about the fourth power of ion velocity. Secondary electrons were observed for primary ion impacts >5 km/s, regardless of mass, and no evidence of a velocity (detection) threshold was observed. Copyright 2000 John Wiley & Sons, Ltd.
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Affiliation(s)
- G Westmacott
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
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