American Society For Mass Spectrometry Research Articles

John Herbert Beynon. 29 December 1923—24 August 2015

John Herbert Beynon was born in a Welsh mining village in 1923, graduated BSc (Hons, physics) at 19, then worked on weapons research for the war effort in World War Two. In 1947 he started a 22-year career at Imperial Chemical Industries (ICI) in Manchester, where, with his technician Albert Williams, he revolutionized mass spectrometry from a physics method to an essential technique for organic chemistry. In 1960 he completed his landmark book Mass spectrometry and its applications to organic chemistry , which was reprinted by the American Society for Mass Spectrometry as a ‘Classic Book’. He continued his creative work in 1969–1974 at Purdue University. In 1974 he started his Royal Society Research Professorship at Swansea University, his alma mater. Collaborations here with a long string of students, postdoc, visiting professors and scientists from many countries resulted in about 65% of his list of 395 peer-reviewed publications. His unexpected retirement led to a compendium of 32 articles in his honour. He then initiated and edited a new journal, Rapid Communications in Mass Spectrometry .

Professor Rodinei Augusti, an enthusiast for the progress of chemistry in Brazil, kindly spoke to BrJAC

Rodinei Augusti holds a degree in chemistry (1986), a master’s degree in chemistry (1990), and a doctorate in chemistry (1993), all from the University of Campinas (UNICAMP), SP, Brazil. Currently, he is a full professor in the Department of Chemistry, Institute of Exact Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, MG, Brazil. He conducts research on the application of mass spectrometry in several areas, such as monitoring reactions of environmental interest and quality control of alcoholic beverages. Prof. Augusti is an advisor to the following journals: Rapid Communications in Mass Spectrometry, Journal of Mass Spectrometry, Analytical Chemistry, Inorganic Chemistry, Journal of the Brazilian Chemical Society, Analyst (London), Journal of the American Society for Mass Spectrometry, and Quimica Nova.

Resolution and Resolving Power in Mass Spectrometry.

The term resolution is one of the most important in mass spectrometry because it describes the ability to separate peaks in mass spectra. The term resolving power is often used to describe the ability of a mass spectrometer to resolve adjacent peaks in a mass spectrum and is often used interchangeably with resolution. The separation of peaks for singly charged ions can be expressed as a mass difference Δm and the ratio m/Δm is often given as a quantitative measure of the ability of a mass spectrometer to separate ions. Over the past 50 years, several definitions of mass resolution and mass resolving power have been recommended both by the International Union for Pure and Applied Chemistry and the American Society for Mass Spectrometry that define both resolution or resolving power as m/Δm which has led to confusion about the proper use of these terms. The goal of this work is to investigate the origins and use as well as prior and current definitions of resolution and resolving power and make recommendations for the definition of these terms.

What Are Essential Skills and Concepts for Teaching Mass Spectrometry to Undergraduates?

Instructors of college-level science courses often have a strong desire to use techniques and concepts from the fields of educational psychology and pedagogy, but it can be difficult to adapt information from those fields to specific technical topics such as mass spectrometry. A useful technique to apply various learning theories to teaching a specific topic is to distinguish between skills and concepts that are needed to understand and apply that topic to various problems. This report summarizes information gathered at the American Society for Mass Spectrometry 2021 Undergraduate Research Interest Group Workshop and seeks to identify essential skills and concepts that need to be taught to undergraduate students learning about mass spectrometry. Some recommendations are made for how members of the mass spectrometry community can engage with their institutions to enhance mass spectrometry education.

Review of the ASMS 2021 Fall Workshop on MALDI Imaging Mass Spectrometry.

ADVERTISEMENT RETURN TO ISSUEPREVConference ReviewNEXTReview of the ASMS 2021 Fall Workshop on MALDI Imaging Mass SpectrometryPeggi M. Angel*Peggi M. AngelMedical University of South Carolina, Charleston, South Carolina 29425, United States*Email: [email protected]More by Peggi M. Angelhttps://orcid.org/0000-0002-4436-555XCite this: J. Am. Soc. Mass Spectrom. 2022, 33, 3, 407–408Publication Date (Web):February 11, 2022Publication History Received24 January 2022Accepted26 January 2022Published online11 February 2022Published inissue 2 March 2022https://doi.org/10.1021/jasms.2c00026Copyright © 2022 American Society for Mass Spectrometry. Published by American Chemical Society. All rights reserved.RIGHTS & PERMISSIONSArticle Views284Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (531 KB) Get e-Alerts Get e-Alerts

Building a Differential Electrochemical Mass Spectrometry (DEMS): A Powerful Toll for Investigation of (photo)Electrochemical Processes

The development of electrochemical devices more efficient for energy conversion and storage are a challenge for modern society. Among this class of devices, fuel cells, batteries, and photovoltaic cells stand out. Despite their importance and practicality, the electrochemical processes that take place in these devices are not always easily understood. In addition, the detection and identification of the products and intermediaries, as well as the reaction paths usually are extremely complex, due to the different species produced and also several reaction steps that take place simultaneously in this type of system. In this context, analytical techniques have been combined to electrochemistry systems to investigate the electrochemical processes in real-time. FTIR (infrared spectroscopy with Fourier transform), MS (mass spectrometry) are some of examples that coupled techniques. Therefore, these setups provide great opportunities for the electrochemistry field, which also includes catalysts design improvement and reaction investigations under different experimental conditions.1-3 The electrochemical mass spectrometry (EMS) technique has stood out as an important tool for the identification and analyses of qualitatively/quantitatively gaseous, volatile intermediates, and products generated during electrochemical reactions. The interface between the mass spectrometer’s high-vacuum system and the electrochemical cell’s room pressure was composed of a hydrophobic porous membrane connected to the inlet system. The ionic current intensity associated with the products was monitored and correlated to the faradaic current3. In 1984 Wolter and Heitbaum4 refined the Electrochemical Mass Spectroscopy technique, employing a new vacuum system design consisting of two pumping stages, giving high sensitivity to the technique and allowing the on-line detection of gaseous with response-time ≤ 0.5 s, four times faster than the first setup developed. The Wolter and Heitbaum’s method was called Differential Electrochemical Mass Spectroscopy (DEMS). Here, differential pumping is related to a two-stage pressure reduction, where the gas flow is initially expanded to a low vacuum and later to a high vacuum, where the mass spectrometer is located4. This work presents the instrumental design used to construct a DEMS to investigate and elucidate (photo)electrochemical reactions. The DEMS design selected was composed of a two-stage differentially pumped vacuum system (Figure 1(I)). The instrument is composed of three main sections: electrochemical cell; hydrophobic microporous membrane, and mass spectrometer, including the vacuum system (turbomolecular and pre-vacuum pumps). The electrochemical cell used, was employed initially by Baltruschat5, this cell use a modified Polytetrafluoroethylene (PTFE) porous membrane interface as the working electrode, which is prepared by metal sputtering onto a microporous membrane.An example of the relation between cyclic voltammogram (CV) and mass-spectrum cyclic voltammograms (MSCV) using the DEMS constructed in this work is shown in Fig. 1((II)a-b), respectively (CVs only in H2SO4 is presented as an insert in Fig. 1(a)). The working electrode was sputtered of platinum (50 nm thickness) onto the PTFE microporous membrane interface. The counter electrode was a platinum mesh with a high surface area, the reference electrode was a reversible hydrogen electrode (RHE). The electrochemical cell was directly attached to the pre-vacuum chamber of the mass spectrometer High purity N2 was used to de-aerate the solution.The cyclic voltammograms were recorded at a sweep rate of 10 mV s-1. While the faradaic current and the ion mass current for the generated product, CO2 (m/z = 44 (CO2 +), were monitored at the same time. Fig. 1(c-e) shows the faradaic (d) and ionic currents (e) profiles vs. time obtained for 6 CVs, the potential is also presented. As can be observed, the faradaic current has an excellent correlation with the ionic current, conducting to a great synchronization between the voltammetric scans and the ionic signal profile. Besides, the results show a significant deactivation of the electrocatalyst, which is followed by the ionic signal (m/z = 44). As reported in the literature6, the formic acid electrooxidation produces a poison intermediate, which is formed from the dissociative adsorption of formic acid on the electrode surface, this poison specie was posteriorly identified as CO. Therefore, the DEMS technique can provide important information to determine the reaction mechanisms. Bashyam, R.; Zelenay, P., Nature 2006, 443 (7107), 63-66. Bruckenstein, S.; Gadde, R. R., Journal of the American Chemical Society 1971, 93 (3), 793-794. Chen, A.; Lipkowski, J., The Journal of Physical Chemistry B 1999, 103 (4), 682-691. Wolter, O.; Heitbaum, J., 1984, 88 (1), 2-6. Baltruschat, H., Journal of the American Society for Mass Spectrometry 2004, 15 (12), 1693-1706. Herrero, E.; et al.., Journal of Electroanalytical Chemistry 1993, 350 (1), 73-88. Figure 1

Michael S. Bereman (1981–2021)

ADVERTISEMENT RETURN TO ISSUEPREVObituaryNEXTMichael S. Bereman (1981–2021)David C. Muddiman*David C. MuddimanDepartment of Chemistry and Molecular Education, Technology and Research Innovation Center (METRIC), North Carolina State University, 2620 Yarbrough Drive, Raleigh, North Carolina 27695, United States*Email: [email protected]More by David C. Muddiman and Michael J. MacCoss*Michael J. MacCossGenome Sciences, University of Washington, Box 355065, Foege S113 3720 15th Ave NE, Seattle, Washington 98195-5065, United States*Email: [email protected]More by Michael J. MacCossCite this: J. Am. Soc. Mass Spectrom. 2021, 32, 5, 1272–1274Publication Date (Web):May 5, 2021Publication History Received11 April 2021Accepted14 April 2021Revised13 April 2021Published online5 May 2021Published inissue 5 May 2021https://doi.org/10.1021/jasms.1c00129Copyright © 2021 American Society for Mass Spectrometry. Published by American Chemical Society. All rights reserved.RIGHTS & PERMISSIONSArticle Views1295Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-AlertsSUBJECTS:Mass spectrometry,Students,Diagnosis,Proteomics,Kinetics Get e-Alerts

Tools for quantitative analysis: The Al Yergey perspective.

The development of a reliable quantitative method for a specific application requires consideration of several important principles. Although mass spectrometry has become the "gold standard" for sensitive and precise multicomponent quantification, it does not necessarily follow that all quantitative data generated by mass spectrometry are either precise or accurate. Depending on the nature of the sample and the goal of the assay, the endeavor can be challenging. With attention to some critical concerns, valid results can be obtained; without attention to these concerns, results can be misleading and, in some instances, invalid. For almost 10 years, beginning in 1996, the authors of this article, together with their friend and colleague Al Yergey, taught an American Society for Mass Spectrometry (ASMS) Short Course on the principles of quantitative mass spectrometry. In this Special Feature, we revisit and update some of these principles. We pay special attention to the contributions of Al Yergey to the course that not only enriched our own understanding of quantitative analysis but also had a measurable impact on the entire field of mass spectrometry.

Thoughts on Writing for Review: An NSF Program Officer's Perspective.

This is an invited Account and Perspective, providing observations and advice derived from a 40 year academic career that has included over 14 years' service as a program officer at the National Science Foundation (NSF) and 27 years of service as an Associate Editor of the Journal of the American Society for Mass Spectrometry. This work describes the program officer's perspective, with observations on what reviewers look for in proposals, and what are some of the more common, best avoided mistakes. Emphasis is on NSF guidelines, but many elements are general and intended for use by both proposal authors and reviewers.

Thoughts on Writing for Review: A Former JASMS Associate Editor's Perspective.

This is an invited Account and Perspective, providing observations and advice on writing for review derived from a 40-year academic career that has included 27 years' service as an Associate Editor for the Journal of the American Society for Mass Spectrometry (JASMS) and nearly 14 years at the National Science Foundation. This work describes an Associate Editor's perspective. It offers observations on what editors and reviewers look for in manuscripts and some of the more common, best avoided mistakes. Emphasis is on JASMS guidelines, but many elements should be generally applicable and are intended for use by both authors and reviewers.

To Improve Is To Change···Again

ADVERTISEMENT RETURN TO ISSUEEditorialNEXTTo Improve Is To Change···AgainJoseph A. LooJoseph A. LooMore by Joseph A. Loohttp://orcid.org/0000-0001-9989-1437Cite this: J. Am. Soc. Mass Spectrom. 2020, 31, 1, 1Publication Date (Web):January 2, 2020Publication History Received10 December 2019Accepted16 December 2019Published online2 January 2020Published inissue 2 January 2020https://doi.org/10.1021/jasms.9b00126Copyright © 2020 American Society for Mass Spectrometry. Published by the American Chemical Society. All rights reserved.RIGHTS & PERMISSIONSArticle Views599Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (361 KB) Get e-AlertsSUBJECTS:Mass spectrometry,Peptides and proteins,Quality management,Analytical chemistry,Ionization Get e-Alerts

Perspectives on Data Analysis in Metabolomics: Points of Agreement and Disagreement from the 2018 ASMS Fall Workshop.

In November 2018, the American Society for Mass Spectrometry hosted the Annual Fall Workshop on informatic methods in metabolomics. The Workshop included sixteen lectures presented by twelve invited speakers. The focus of the talks was untargeted metabolomics performed with liquid chromatography/mass spectrometry. In this review, we highlight five recurring topics that were covered by multiple presenters: (i) data sharing, (ii) artifacts and contaminants, (iii) feature degeneracy, (iv) database organization, and (v) requirements for metabolite identification. Our objective here is to present viewpoints that were widely shared among participants, as well as those in which varying opinions were articulated. We note that most of the presenting speakers employed different data processing software, which underscores the diversity of informatic programs currently being used in metabolomics. We conclude with our thoughts on the potential role of reference datasets as a step towards standardizing data processing methods in metabolomics.

ACS to publish JASMS

ACS will begin publishing the Journal of the American Society for Mass Spectrometry (JASMS) under a new partnership between ACS Publications and the American Society for Mass Spectrometry. The journal is a leading publication in the field of measurement science and mass spectrometry research, and this new partnership aims to provide it with an even broader global reach. Submissions to JASMS will switch to ACS Paragon Plus this fall, with the first issue published under this new partnership appearing online in January 2020. “ASMS was seeking a new publishing partner to provide state-of-art technology and editorial support to facilitate the work of our editors and to enhance the experience of authors and readers. ACS was the obvious choice,” says Richard A. Yost, president of the Journal of the American Society for Mass Spectrometry. “ACS Publications is known for its collection of world-class science journals. We are proud that JASMS will

Cracking the Sugar Code by Mass Spectrometry

The structural study of glycans and glycoconjugates is essential to assign their roles in homeostasis, health, and disease. Once dominated by nuclear magnetic resonance spectroscopy, mass spectrometric methods have become the preferred toolbox for the determination of glycan structures at high sensitivity. The patterns of such structures in different cellular states now allow us to interpret the sugar codes in health and disease, based on structure-function relationships. Dr. Catherine E. Costello was the 2017 recipient of the American Society for Mass Spectrometry’s Distinguished Contribution Award. In this Perspective article, we describe her seminal work in a historical and geographical context and review the impact of her research accomplishments in the field.8ᅟGraphical abstract

Bibliometric Analyses Reveal Patterns of Collaboration between ASMS Members

We have explored the collaborative network of the current American Society for Mass Spectrometry (ASMS) membership using bibliometric methods. The analysis shows that 4249 members are connected in a single, large, co-authorship graph, including the majority of the most published authors in the field of mass spectrometry. The map reveals topographical differences between university groups and national laboratories, and that the co-authors with the strongest links have long worked together at the same location. We have collected and summarized information on the geographical distribution of members, showing a high coverage of active researchers in North America and Western Europe. Looking at research fields, we could also identify a number of new or ‘hot’ topics among ASMS members. Interactive versions of the maps are available on-line at https://goo.gl/UBNFMQ (collaborative network) and https://goo.gl/WV25vm (research topics).Graphical ᅟ

Liquid chromatography-high-resolution mass spectrometry for regulated bioanalysis: bile acid and oligonucleotide quantitation as a reference.

Liquid chromatography-high-resolution mass spectrometry for regulated bioanalysis: bile acid and oligonucleotide quantitation as a reference.

Identification of Carbon Dioxide Electroreduction Products on Multilayered Metallic Catalysts Based on Palladium

Atmospheric carbon dioxide levels have risen rapidly over the last few decades. Electrochemical conversion of carbon dioxide into eligible fuels has potential as a technology that may prevent from a serious environmental problems. Electroreduction of carbon dioxide to hydrocarbons is a complex process that usually involves adsorbed carbon monoxide as an intermediate. The overall electroreduction path is determined to a large extent by the catalyst’s surface affinity to carbon monoxide and hydrogen. Strongly bounded CO inhibits further reduction while weakly bounded CO easily desorbs as a final product [1]. One of primary step is CO2 adsorption followed by its reduction to absorbed carbon monoxide. The presences of adsorbed atomic hydrogen at the catalyst surface can significantly facilitate the formation of hydrocarbons. However, within the potential range of CO2 reduction in the aqueous solution a competitive reaction of hydrogen evolution (HER) takes place, which can even dominate in the electroreduction processes. Our result points out the possibility of tuning catalyst’s affinities to both hydrogen and CO by designing multilayered structures obtained by sequential UPD strategies [2]. Results show that catalytic activity can be finely tuned by using the multilayered near-surface-alloy approach [3]. Our results clearly demonstrate that the Pd-layer thickness and location significantly changes the surface catalytic activity of palladium toward CO2 electroreduction. Interestingly, multilayered films covered with the silver monolayer largely reflect the properties of palladium deposits existing under the Ag surface. Differential Electrochemical Mass Spectrometry method (DEMS) was used to analyze and determine gaseous products of carbon dioxide electroreduction together with evolved hydrogen. Individual molecules are recognized by ionic current mass signals. DEMS method allows to identify reduction products during faradaic reduction [4]. This technique is particularly useful for investigations of electroinactive molecules such as methane or ethylene. Ion current changes are related to applied potential, and were presented as MS-CV (mass spectrum cyclic voltammograms). MS-CV provide useful information on the formation potentials of each products. Electroactive products and intermediates, such as carbon monoxide and formic acid were also detected by using classical electrochemical methods. For this purpose a palladium electrode was used for detection of CO2 electroreduction products obtained in macroelectrolysis. [1]Jitaru, M., et al., Journal of Applied Electrochemistry, 1997. 27(8): p. 875-889. [2]Januszewska, A., R. Jurczakowski, and P.J. Kulesza, Langmuir, 2014. 30(47): p. 14314-14321. [3]Greeley, J. and M. Mavrikakis. Journal of Physical Chemistry B, 2005. 109(8): p. 3460-3471. [4]Baltruschat, H., Journal of the American Society for Mass Spectrometry, 2004. 15(12): p. 1693-1706.

The H-Index of ‘An Approach to Correlate Tandem Mass Spectral Data of Peptides with Amino Acid Sequences in a Protein Database’

Over 20years ago a remarkable paper was published in the Journal of American Society for Mass Spectrometry. This paper from Jimmy Eng, Ashley McCormack, and John Yates described the use of protein databases to drive the interpretation of tandem mass spectra of peptides. This paper now has over 3660 citations and continues to average more than 260 per year over the last decade. This is an amazing scientific achievement. The reason for this is the paper was a cutting edge development at the moment in time when genomes of organisms were being sequenced, protein and peptide mass spectrometry was growing into the field of proteomics, and the power of computing was growing quickly in accordance with Moore's law. This work by the Yates lab grew in importance as genomics, proteomics, and computation all advanced and eventually resulted in the widely used SEQUEST algorithm and platform for the analysis of tandem mass spectrometry data. This commentary provides an analysis of the impact of this paper by analyzing the citations it has generated and the impact of these citing papers. Graphical Abstract ᅟ.

Congratulations for Twenty Years of the European Journal of Mass Spectrometry.

Peter Derrick’s flattering invitation to comment on this mass spectrometry landmark was followed immediately by a requirement for brevity, obviously impossible in discussing the impact of EJMS. But seeing the comprehensive draft of my good friend Hans-Friedrich Grutzmacher, I decided to concentrate instead on the importance of European leadership in mass spectrometry to the success of the whole world’s mass spectrometry. EJMS perceived a key responsibility for this at a crucial time, with their unique contribution deserving of this 20 year celebration. My first national meet was the mass spectrometry section at the 1952 Pittsburgh Analytical Conference with ~40 massspectrometry people, mainly in isotope and hydrocarbon mass spectrometry. Their efforts resulted in the ASTM E-14 Committee whose 1953 meeting is counted as the first for the American Society for Mass Spectrometry (I’m just back from the 2015 ASMS meet in St Louis, having missed only one). E-14/ASMS enjoyed a fast rising attendance, even from around the world. As a great example, John Beynon came from ICI and gave a revolutionary “high resolution” talk in 1955. He even visited my lab in Dow Midland, pushing hard to have AEI make Dow a double-focusing instrument along with his, lowering the price (my refusal has been followed by other stupid decisions). But Al Nier and I were still invited as the US official representatives to the first Triennial International Mass Spectrometry (IMS) Meeting in London, 1958. There I was totally surprised at the fascinating science that was new to me, and with the number of new friends. Subsequently I visited the labs of many who were doing leading research. I well remember the Berlin 1967 IMS with Allan Maccoll proposing Organic Mass Spectrometry; could my field have grown that much? But so many good friends there were enthusiastic (even grad student Helmut Schwarz) that OMS started in 1968. Its success was immediate with wonderful world publicity for European mass spectrometry, also helping recognition for ASMS and from JACS and Anal. Chem. A 1976 sabbatical with Morrison and Derrick gave me further on-site exposure to exciting research and hospitality across Australia, promising not to tell the CIA about isotope separation with Jim and Peter’s huge new four-sector instrument. IMS meetings continued to be great (I attended all until a few years ago), but before the 1986 meet, Chair John Beynon complained to me that still only ~40 attended from the US. So from NSF we badgered funds for 30 travel awards with paper acceptance required, so almost all of the 70 applicants plus ~70 others attended. Provincial mass-spectrometry Americans found that they could enjoy international competition, more publicity needed! After that the meeting was truly international, e.g., with Nico Nibbering as Chair, igloos had IMS posters. By then, however, greater change was everywhere in mass spectrometry, even with exciting new science not in “interpretation of mass spectra” (how could that be?). Wise leadership forecast that a broad, innovative new mass spectrometry journal was critical, and in 1995 appeared the European Journal of Mass Spectrometry! The rest may be history to most of you faithful readers, but I reserve my extra hoorah! until reading this special EJMS issue. F. McLafferty, Eur. J. Mass Spectrom. 21, xi (2015)

Ion mobility-mass spectrometry: time-dispersive instrumentation.

The field of ion mobility-mass spectrometry (IM-MS) has grown with significant momentum in recent years in both fundamental advances and pioneering applications. A search of the terms “ion mobility” and “mass spectrometry” returns more than 2 000 papers, with over half of these being published in the past 4 years (Figure ​(Figure1,1, left). This increased interest has been motivated in large part by improved technologies which have enabled contemporary IM-MS to be amendable to a variety of samples in biology and medicine with high sensitivity, resolving power, and sample throughput. Figure 1 (Left) Histogram of the number of publications published per year in ion mobility and ion mobility-mass spectrometry. Note that the scale is truncated at 300 to highlight the number of publications specifically utilizing IM-MS. Further distinction is ... Highlights of the historical development of the field are presented in Figure ​Figure1,1, right. Ion mobility and mass spectrometry trace their foundations to the X-ray experiments of Thomson and Rutherford in the late 1800s,1 with Tyndall making significant improvements in the analytical capabilities of ion mobility around the 1930s.2,3 During this early era of discovery, a variety of ion mobility experimental parameters were explored, including differences in pressure,4,5 temperature,6,7 electric field,8 and the ion residence time (age) in the drift region.9 Hybrid IM-MS instruments of various configurations were developed by several groups in the 1960s to study gas-phase ion chemistry.10−12 Ion mobility measurements were used by Dole in the earliest development of electrospray ionization (ESI).13,14 Following commercialization,15 ion mobility instrumentation was used for structure-based characterization16 and differentiation of chemical isomers.17,18 In 1982, laser ionization was demonstrated with ion mobility as a means of generating simplified mobility spectra based on protonated species.19 The features which define modern IM-MS, namely, high resolution, high sensitivity, and broad sample compatibility, were developed in the 1990s and coincided with the rapid development of MS in response to the introduction of ESI and MALDI sample ionization.20−22 The last 2 decades saw significant improvements made in the coupling of IM to MS, notably the use of electrodynamic fields to confine, transfer, and focus ions across disparate pressure regions into high vacuum. An interesting observation to be made in this historical analysis is that many of the features we associate with contemporary ion mobility technology were key aspects of early ion mobility instrument design. Several noteworthy reviews of IM-MS have been published, which cover many aspects of the IM-MS technique and range of applications.23−28 A number of influential books covering various aspects of the ion mobility field are also available.29−34 Of particular relevance is Mason and McDaniel’s Transport Properties of Ions in Gases,35 which was recently republished by the American Society for Mass Spectrometry in their classic books series. Though last revised in 1988, this book is still widely considered the seminal treatment of the motion of ions in gases. The technologies and application areas which IM-MS now encompasses has expanded to such a breadth that new reviews covering IM-MS and related areas now appear every few years in the literature. A comprehensive and critical review of the field as a whole is no longer appropriate nor tractable, and as such it is the intent of this review to focus primarily on recent developments made with regard to temporally dispersive ion mobility techniques (drift tubes and traveling wave separators), with an emphasis on their use specifically in IM-MS instrumentation and methods. This focus is selected because of the recent commercial offerings in this regard that have become widely used in many research environments. The present review is not intended to be comprehensive of the ion mobility advances but rather focuses on time-dispersive IM-MS instrumentation over the past few years.