About

Mark E. Bier is a Research Professor in the Department of Chemistry at Carnegie Mellon University and the Director of the Center for Molecular Analysis. His research involves instrumentation development for mass spectrometry, focusing on improving measurements of matter through innovations in inlet technology, ionization sources, mass analyzers, and detectors. His lab has developed membrane inlet mass spectrometry systems for environmental water analysis and advanced ionization techniques such as nano-electrode atmospheric pressure chemical ionization and mechanospray ionization, including investigations into hot ionization sources. Bier's work in heavy ion mass spectrometry (HIMS) represents a frontier in the analysis of nanoparticles, biomacromolecular complexes, viruses, and other high molecular weight entities. His lab utilizes superconducting tunnel junction cryodetectors to detect ultra-high m/z ions, enabling the analysis of large molecules like viral particles and protein complexes, with the capability to record the highest molecular weight mass spectra to date. His research has significant implications for fields such as molecular biology, virology, and polymer chemistry. In addition to instrumentation development, Bier's research includes environmental water analysis for volatile organics, employing techniques like electrospray ionization and membrane introduction mass spectrometry. He has contributed to the creation of educational tools such as the Virtual Mass Spectrometry Laboratory, aimed at educating students, teachers, and researchers about mass spectrometry. His work has led to numerous publications and innovations in mass spectrometry technology.

Research topics

• Chemistry
• Chromatography
• Organic chemistry
• Waste management
• Engineering
• Environmental science
• Crystallography
• Pulp and paper industry
• Physics
• Composite material
• Materials science
• Environmental engineering
• Environmental chemistry

Selected publications

• Raw Mass Spectra from the Publication "E-Cigarettes Generate Gas Phase Ions"

  KiltHub Repository · 2026-04-01

  datasetOpen accessSenior author

  Data set of mass spectra for the research article "E-Cigarettes Generate Gas Phase Ions" by N. C. Auvil and M. E. Bier published in ACS Environment & Health in 2026.

  PublisherDOI

• E-Cigarettes Generate Gas Phase Ions

  Environment & Health · 2026-04-20

  articleOpen accessSenior authorCorresponding

  Mass spectrometry (MS) evidence shows that electronic cigarettes (e-cigs) can directly emit gas phase ions at levels orders of magnitude greater than detected from typical ambient air or smoke from the mouthpiece of a traditional tobacco cigarette (t-cig). These ions, generated upon atomization of the e-liquid into an e-cig aerosol, are presumably inhaled by e-cig users. Emissions from disposable e-cigs were sampled at atmospheric pressure directly into a mass spectrometer without a conventional ion source. All four e-cigs produced mass spectra with high ion intensities, indicating that their aerosols were ion-rich upon exiting the mouthpieces. While multiple ionization pathways may contribute, atmospheric pressure thermospray ionization (APTSI) appeared to be the dominant pathway. The e-cig self-ionization process provides a direct method of aerosol analysis by mass spectrometry (MS) and eliminates the need for precollection and conventional MS ion sources. This finding has implications for e-cig user exposure that warrant further mechanistic and toxicological study.

  PublisherDOI

• Raw Mass Spectra from the Publication "E-Cigarettes Generate Gas Phase Ions"

  KiltHub Repository · 2026-04-01

  datasetOpen accessSenior author

  Data set of mass spectra for the research article "E-Cigarettes Generate Gas Phase Ions" by N. C. Auvil and M. E. Bier published in ACS Environment & Health in 2026.

  PublisherDOI

• Nanoelectrode Atmospheric Pressure Chemical Ionization Mass Spectrometry

  Journal of the American Society for Mass Spectrometry · 2024-06-25 · 6 citations

  articleOpen accessSenior authorCorresponding

  A small ionization needle with an ultrasharp, ultrafine tip is introduced. It is lab-fabricated from tungsten wire and serves as a corona discharge emitter in nanoelectrode atmospheric pressure chemical ionization mass spectrometry (nAPCI-MS). Tip radii ranged from 8 to 44 nm, up to 44× smaller than the sharpest previously reported corona needle. Because of this, nAPCI was able to operate at +1.0 kV with no auxiliary counter electrode. Alternatively, at +1.2 kV, nAPCI could be enclosed in a small plastic assembly for headspace analysis with a sampling tube attachment as long as 15 m. No added heat or gas flow was necessary. The efficacy of nAPCI-MS was demonstrated through needle durability studies and direct analysis of vapors from real-world samples. Provisional identifications include ibuprofen from a pharmaceutical tablet, albuterol aerosol sprayed from a medical inhaler, cocaine from paper currency, caffeine from a fingertip, and bisphenol E from a paper receipt.

  PublisherDOI

• Mechanospray Ionization MS of Proteins Including in the Folded State and Polymers

  Journal of the American Society for Mass Spectrometry · 2022 · 8 citations

  Senior authorCorresponding
  • Chemistry
  • Chromatography
  • Crystallography

  2016, 424-429) and under native conditions, the retention of proteins in one or more presumed folded structures and for holomyoglobin the high retention of the heme group. When analyzing polyethylene glycol (PEG) and polypropylene glycol (PPG), MoSI also generated a broader distribution to lower charge states than ESI. By using the improved separation of peaks at lower charge states and all the charge states available, MoSI data should provide an improved ionization method to obtain more accurate mass and dispersity values for some polymers.

  PublisherDOI

• Mass Spectrometry of Au₁₀(4-<i>tert-</i>butylbenzenethiolate)₁₀ Nanoclusters Using Superconducting Tunnel Junction Cryodetection Reveals Distinct Metastable Fragmentation

  Journal of the American Society for Mass Spectrometry · 2022-02-11 · 7 citations

  articleSenior authorCorresponding

  Cryodetection mass spectrometry (MS) was used to study the Au10(TBBT)10 (TBBT = 4-tert-butylbenzenethiolate) catenane nanocluster. The matrix-assisted laser desorption ionization (MALDI) process generates distinct fragments that can be arranged into two distinct regimes: (i) in-source fragmentation, which occurs rapidly in a relatively short (<170 ns) time frame, and (ii) metastable fragmentation, which occurs postacceleration during a time-of-flight (TOF) mass analysis over a longer time frame (>170 ns–250 μs). Using MALDI-TOF MS with superconducting tunnel junction (STJ) cryodetection, distinct metastable nanocluster fragments were resolved at lower energies deposited into the detector. The results also demonstrated that STJ cryodetection MS can be used to acquire multiple (>10), simultaneous tandem mass spectra in a single experiment. Simulated fragmentation of the Au10 nanocluster using ab initio molecular dynamics (AIMD) revealed the different fragmentation processes and confirmed the MS results. Using both the empirical MS data and AIMD calculations, fragmentation pathways are proposed for Au10(TBBT)10, which terminate with two small, stable ringed species.

  PublisherDOI

• Watching Paint Dry: Organic Vapor Emissions from Architectural Coatings and their Impact on Secondary Organic Aerosol Formation

  Environmental Science & Technology · 2022 · 20 citations

  • Environmental science
  • Environmental chemistry
  • Environmental engineering

  μg/g-paint. Emissions from interior paints are dominated by VOCs, whereas exterior-use paints emitted a larger fraction of IVOCs. Extended emission tests showed that most I/VOC emissions occur within 12-24 h after paint application, though some paints continue to emit IVOCs for 48 h or more. We used our data to estimate paint I/VOC emissions and the subsequent SOA production in the U.S. Total annual paint I/VOC emissions are 48-155 Gg (0.15-0.48 kg/person). These emissions contribute to the formation of 2.2-7.5 Gg of SOA annually. Oil-based paints contribute 70-98% of I/VOC emissions and 61-99% of SOA formation, even though they only account for a minority of paint usage.

  PublisherDOI

• Anatomy of Protein Electrospray Ionization Mass Spectra by Superconducting Tunnel Junction Mass and Energy Spectrometry

  Analytical Chemistry · 2022 · 5 citations

  Senior authorCorresponding
  • Chemistry
  • Chromatography
  • Physics

  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.

  PublisherOA PDFDOI

• Watching Paint Dry: I/VOC Emissions from Architectural Coatings and their Impact on SOA Formation

  2021-08-13

  preprintOpen access

  Emissions from volatile chemical products (VCPs) are emerging as a major source of anthropogenic secondary organic aerosol (SOA) precursors. Paints and coatings are an important class of VCPs that emit both volatile and intermediate volatility organic compounds (VOCs and IVOCs). In this study, we directly measured I/VOC emissions from representative water-based (latex) and oil paints used in the U.S. Paint I/VOC emissions vary over several orders of magnitude by both solvent and gloss level. Oil paint had the highest emissions (&gt;10^5 microgram/g-paint) whereas low-gloss interior paints (Flat, Satin, and Semigloss) all emitted ~10^2 microgram/g-paint. Emissions from interior paints are dominated by VOCs, whereas exterior-use paints emitted a larger fraction of IVOCs. Extended emissions tests showed that most I/VOC emissions occur within 12-24 hours after paint application, though some IVOC-dominated paints continue to emit for 48 hours or more. We used the emissions measurements to estimate paint I/VOC emissions and subsequent SOA production in the U.S. Total annual paint I/VOC emissions are 168 +/- 15 Mg. This amounts to 291 g/kg of paint used and 0.51 kg/person, which are significantly larger than comparable emissions factors from combustion systems. These emissions contribute to the formation of 8 Mg of SOA annually. Oil paints contribute ~90% of the I/VOC emissions and SOA formation, even though it only accounts for ~20% of paint usage.

  PublisherOA PDFDOI

• Watching Paint Dry: I/VOC Emissions from Architectural Coatings and their Impact on SOA Formation

  ChemRxiv · 2021-08-13

  preprintOpen access

  Emissions from volatile chemical products (VCPs) are emerging as a major source of anthropogenic secondary organic aerosol (SOA) precursors. Paints and coatings are an important class of VCPs that emit both volatile and intermediate volatility organic compounds (VOCs and IVOCs). In this study, we directly measured I/VOC emissions from representative water-based (latex) and oil paints used in the U.S. Paint I/VOC emissions vary over several orders of magnitude by both solvent and gloss level. Oil paint had the highest emissions (&gt;10^5 microgram/g-paint) whereas low-gloss interior paints (Flat, Satin, and Semigloss) all emitted ~10^2 microgram/g-paint. Emissions from interior paints are dominated by VOCs, whereas exterior-use paints emitted a larger fraction of IVOCs. Extended emissions tests showed that most I/VOC emissions occur within 12-24 hours after paint application, though some IVOC-dominated paints continue to emit for 48 hours or more. We used the emissions measurements to estimate paint I/VOC emissions and subsequent SOA production in the U.S. Total annual paint I/VOC emissions are 168 +/- 15 Mg. This amounts to 291 g/kg of paint used and 0.51 kg/person, which are significantly larger than comparable emissions factors from combustion systems. These emissions contribute to the formation of 8 Mg of SOA annually. Oil paints contribute ~90% of the I/VOC emissions and SOA formation, even though it only accounts for ~20% of paint usage.

  PublisherDOI

Recent grants

• Fundamental Mass Spectrometry Measurements of Electrosprayed and Matrix-Assisted Laser Desorbed Ions Using an Improved Superconducting Tunnel Junction Detector

  NSF · $464k · 2016–2021

• Development of a Mega-Dalton Mass Spectrometer for Biological Research

  NSF · $550k · 2005–2011

Frequent coauthors

• R. Graham Cooks

  Purdue University West Lafayette

  8 shared

• Rongchao Jin

  Carnegie Mellon University

  8 shared

• Brigitte F. Schmidt

  Imaging Center

  5 shared

• Logan D. Plath

  Carnegie Mellon University

  5 shared

• Eric J. Lanni

  University of Illinois Urbana-Champaign

  4 shared

• Beate Cürten

  Carnegie Mellon University

  4 shared

• Huifeng Qian

  Shaoxing Second Hospital

  4 shared

• Liam Dugan

  4 shared

Education

• Ph.D.

  Purdue University

  1988

• B.S.

  Purdue University

• M.S.

  Purdue University

• B.A.

  Purdue University

• M.A.

  Purdue University

• Other

  AMSCO Inc. (Steris)

  1983

• Other

  VA Medical Center

  1981

Awards & honors

• Co-inventor of the linear quadrupole ion trap used worldwide