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Michael Van Stipdonk, Ph.D.

Associate Professor
Bayer School of Natural and Environmental Sciences
Department of Chemistry and Biochemistry

Mellon Hall
Phone: 412.396.4923

Education:

Post-doctoral Research Associate, Texas A&M University, 1994-1996
Ph.D., Chemistry, Texas A&M University, 1994
B.A., Chemistry, University of Detroit, 1989
Bio

Dr. Michael Van Stipdonk is an Associate Professor in the Department of Chemistry and Biochemistry at Duquesne. He is also the co-director of the Agilent Center of Excellence in Mass Spectrometry.

Dr. Van Stipdonk received a B.A. degree in Chemistry from the University of Detroit. He earned a Ph.D. in chemistry from Texas A&M University. The subject of his dissertation was the emission of secondary ions from solid surfaces following energetic ion impacts, and the use of this emission to determine nano-scale molecular composition. In his post-doctoral research, also at Texas A&M, Dr. Van Stipdonk was a leading figure in the introduction of polyatomic primary ions for surface analysis by secondary ion mass spectrometry.

Dr. Van Stipdonk began his academic career at Wichita State University, where his research areas included studies of peptide fragmentation mechanisms using tandem mass spectrometry and general trends (thermodynamic and kinetic) in gas-phase ion chemistry. This research continues at Duquesne, where his group is advancing the use of tandem mass spectrometry and ion spectroscopy to determine reactant and product ion composition and structure.

Dr. Van Stipdonk awards and honors include a National Science Foundation CAREER grant and the Kansas Biomedical Infrastructure Faculty-Scholar Award. He is a member of the editorial board of the Journal of the American Society for Mass Spectrometry (ASMS). As a member of the ASMS he has served as coordinator for the surface science, metal ions, and peptide fragmentation interest groups and chaired numerous technical sessions at the society’s annual meeting. He is also a member of the American Chemical Society.

Research

Research Program Summary

Undergraduate and graduate students in the van Stipdonk research group use ion trap mass spectrometry, spectroscopy and theory to study a variety of chemical processes in the gas-phase. As summarized below, our current research projects can be grouped into three general areas: (a) fundamental studies of peptide ion dissociation to support application of tandem mass spectrometry (tandem MS) to peptide and protein identification in proteomics; (b) studies of the intrinsic stability and reactivity of metal ion complexes important to biology, energy production and the environment, and (c) vibrational spectroscopy of gas-phase ions using wavelength-selective infrared multiple-photon photodissociation. Besides extensive use of mass spectrometry and tandem MS, work in our laboratory involves the synthesis of model molecules and peptides, including those with isotope labels, and use of density functional theory (DFT) to predict ion structures, energies and vibrational spectra. Our work on tandem MS and peptide dissociation has been funded by the National Science Foundation (NSF). Studies of intrinsic metal ion chemistry have been supported by the U.S. Department of Energy and the Idaho National Laboratory. Work on ion spectroscopy is supported in part by the NSF, the Institue for Molecules and Materials, Radboud University Nijmegen; and the Nederlandse Organisatie voor Wetenschappelijk Onderzoek. Over the past decade, the experiments in these areas have led to over 85 manuscripts published or submitted for publication in peer-reviewed journals such as Journal of Physical Chemistry A, Journal of the American Society for Mass Spectrometry, Physical Chemistry-Chemical Physics and the Journal of the American Chemical Society.

Fundamental studies of peptide dissociation using tandem mass spectrometry

Mass spectrometry (MS) and tandem MS are important tools used to identify peptides and proteins in proteomics. One focus of our research program is to improve protein and peptide identification by optimizing multiple-stage tandem MS approaches to sequence determination. In proteomics, collision-induced dissociation (CID) of protonated peptides is used to identify peptides, either directly through an interpretation of fragmentation patterns, or indirectly using comparison to fragment ion spectra in databases. For direct sequence determination, however, CID of metal [alkali and Ag(I)] cationized peptides offers potential advantages, particularly when coupled with multiple-stage tandem MS experiments. Our work in this area has demonstrated that sequence, choice of cationizing agent (proton or metal ion), and modification of the N-terminus all significantly influence the CID pathways of model peptides. Optimization of the multiple-stage tandem MS method is therefore critical if the unparalleled combination of speed, sensitivity and selectivity of MS is to be applied to its fullest potential to accurate identification of peptides and proteins in proteome studies.

When using tandem MS, the signal that we interpret, and use to determine structure and composition is provided by chemical (fragmentation) reactions. Accuracy in structure and composition assignment, therefore, depends on accurate interpretation of this chemical signal. A second objective of our research program is to provide a better understanding of gas-phase peptide dissociation mechanisms. In this work solid-phase synthesis is used to create model peptides that allow us to explore fragmentation pathways. An example is our ongoing study of rearrangement reactions that “scramble” sequence information for protonated peptides. Our combined experimental and theoretical approach allows for detailed investigation of the scrambling and rearrangement reactions that take place in CID of b and a ions. We found, using the synthetic analogues of YAGFL, that low energy CID of the b5 fragments of the peptides produces nearly the same dissociation patterns, regardless of the original peptide sequence. More importantly, we also found that CID of protonated cyclo-(YAGFL) generates the same fragments with nearly identical ion abundances when similar experimental conditions are applied. This observation in particular suggested that rapid cyclization of the primarily linear b5 ions takes place on the timescale of CID experiments in both quadrupole ion trap and qTOF instruments, and that the CID spectrum is indeed determined by the fragmentation behavior of the cyclic isomer. We are now extending the work to investigate how the size of b ions, their specific sequence, and the presence of nucleophilic side groups (for example, those of lysine, glutamine and aspargine residues) can influence sequence scrambling.

To support theoretical studies of fragmentation reactions, in particular to measure relative barrier heights for dissociation reactions for direct comparison to theory, we have begun threshold CID experiments in collaboration with Peter Armentrout at the University of Utah. Our ultimate goal is to calibrate less demanding ion-trap CID measurements using the accurate thermochemical information provided by the threshold measurements. Relative collision energies required to activate various pathways are measured, and the influence of structure and sequence on these energies established. Initial Ion trap CID experiments with AGG, GAG and GGA (using variable energy and variable time ion trap CID experiments) suggest that energy required to produce the dominant sequence ion, b2+, is sensitive to the position of the A residue, with an observed trend GGA > AGG > GAG. The threshold for generation b2+ is lower by ~ 1 eV (center of mass frame) compared to other products such as b3+ and y2+, consistent with the lower energy (multiple collision) ion trap CID experiments. Similar results were observed for the other peptides in the group.

Representative publications (*indicates an undergraduate student author):

  1. Apparent Inhibition by Arginine of Macrocyclic b Ion Formation from Singly Charged Protonated Peptides, S. Molesworth and M. J. van Stipdonk, J. Am. Soc. Mass Spectrom., 21, 1322–1328 (2010).
  2. Influence of Size on Apparent Scrambling of Sequence During CID OF b-Type Ions, S. Molesworth, S. M. Osburn* and M. Van Stipdonk, J. Am. Soc. Mass Spectrom, 20, 2174-2181 (2009).
  3. Sequence Scrambling Fragmentation Pathways of Protonated Peptides, C. Bleiholder, S. Osburn*, A. B. Young, S. Suhai, M. Van Stipdonk, A. G. Harrison, B. Paizs, J. Am. Chem. Soc., 130, 17774-17789 (2008).
  4. Structure and Reactivity of an and an* Ions Investigated using Isotope labeling, Tandem Mass Spectrometry and Density Functional Theory Calculations, B. Bythell, S. Molesworth, S. Osburn*, T. Cooper, B. Paizs and M. Van Stipdonk, J. Am. Soc. Mass Spectrom., 19, 1788-1798 (2008).
  5. Formation of (b3-1+cat)+ Ions from Metal-cationized Tetrapeptides Containing β-alanine, γ-aminobutyric acid or ε-aminocaproic Acid Residues, S. M. Osburn*, S. O. Ochola, E. R. Talaty and M. J. Van Stipdonk, J. Mass Spectrom., 43, 1458-1469 (2008).
  6. Influence of a 4-aminomethylbenzoic acid Residue on Competitive Fragmentation Pathways during CID of Metal Cationized Peptides, S. Osburn*, S. Ochola, E. Talaty and M. Van Stipdonk, Rapid Comm. Mass Spectrom., 21, 3409-3419 (2007).
  7. Collision-induced dissociation of Protonated Tetrapeptides Containing β-Alanine, γ-Aminobutyric Acid, ε-Aminocaproic Acid or 4-Aminomethylbenzoic Acid Residues, E. R. Talaty, T. J. Cooper, S. M. Osburn* and M. J. Van Stipdonk, Rapid Comm. Mass Spectrom., 20, 3443-3455 (2006).
  8. Isotope Labeling and Theoretical Study of the Formation of a3* Ions from Protonated Tetraglycine, T. J. Cooper, E. Talaty, J. Grove, S. Suhai, B. Paizs and M. J. Van Stipdonk, J. Am. Soc. Mass Spectrom.,17, 1654-1664 (2006).

Intrinsic stability and reactions of gas-phase metal ion complexes

In the dynamic realm of solution-phase coordination chemistry, formation and stability of complexes is controlled by coordination, geometry, oxidation state, and cooperative effects between different ligands. Probing these aspects provides glimpses of general metal ion chemistry, which leads to an understanding of electronic structure and bonding preferences that could eventually be exploited in new chemical reactions and processes. The problem is, the solution-phase environment of metal ions can be complicated. Changes in speciation are necessarily multiple-step reactions that include participation of many mixed-ligand species, which undergo dissociation and ligand addition on a continuous basis. In this complex environment it is nearly impossible to probe chemistry in a species-explicit fashion, and hence conclusions derived from solution-phase studies tend to be statistical descriptions. Our experimental approach to overcome this problem is to move the investigations into the gas-phase environment of an ion-trap mass spectrometer (ITMS), and slow down chemical reactions to allow specific metal ion complexes to be studied explicitly.

In this part of our research program, the tandem mass spectrometry capabilities of the ITMS are used to elucidate complex structure, determine relative stability and to probe general patterns in chemical reactivity. These studies rely on our ability to transfer metal ion complexes from solution using electrospray ionization (ESI) or from surfaces by ion-induced sputtering, to a low pressure gas-phase environment. Here, ions can be selectively isolated and stored for time periods ranging from milliseconds to seconds. After isolation of a particular ion, composition and structure can be inferred, and stability is measured, using collision-induced dissociation. Ion reactivity can instead be investigated by allowing stored ions to interact with neutral reagents introduced into the ITMS. Beyond providing fascinating details about intrinsic metal complex chemistry, the results of the ITMS experiments on explicitly defined complexes permit direct “apples-to-apples comparisons” with those derived from theoretical (in our case, DFT) calculations. The main focus of our experimental work in this area is on the intrinsic chemistry (dissociation and ligand addition) of complexes that contain first-row transition metals, lanthanides or the uranyl ion. However, experiments with trans-uranic elements are now possible with the recent construction of a radiation-safe ITMS at Lawrence Berkeley National Laboratory (LBL). As visiting scientists at LBL we will build upon our initial uranyl ion experiments to include neptunyl and plutonyl species along with gas-phase complexes composed of the respective elements in a host of alternative oxidation states. Our work will also expand to include oxo-molybdenum and oxo-tungsten complexes that model the active sites of important metalloenyzmes. This work will include mass spectrometry and x-ray absorption spectroscopy experiments at Duquesne University and LBL.

Representative publications (*indicates an undergraduate student author):

  1. Gas-Phase Coordination Complexes of Dipositive Plutonyl, PuVIO22+: Chemical Diversity across the Actinyl Series, D. Rios, P. Rutkowski, M. Van Stipdonk and J. Gibson, Inorg. Chem., 50, 4781–4790 (2011).
  2. Gas-phase Coordination Complexes of UVIO22+, NpVIO22+ and PuVIO22+ with Dimethylformamide, P. X. Rutkowski, D. Rios, J. K. Gibson and M. J. Van Stipdonk, J. Am. Soc. Mass Spectrom. 22, 2042-2048 (2011).
  3. Investigation of Uranyl Nitrate Ion Pairs Complexed with Amide Ligands using Electrospray Ionization Ion Trap Mass Spectrometry and Density Functional Theory, G. Gresham, A. Dinescu, M. Benson, M. Van Stipdonk, G. Groenewold, J. Phys. Chem. A. 115, 3497-3508 (2010).
  4. Cerium Oxyhydroxide Clusters: Formation, Structure and Reactivity, F. Aubriet, J.-J. Gaumet, W. A. de Jong, G. S. Groenewold, A. K. Gianotto, M. E. McIlwain, M. J. Van Stipdonk and C. M. Leavitt*, J. Phys. Chem. A., 113, 6239-6252 (2009).
  5. Addition of H2O and O2 to Acetone and Dimethylsulfoxide Ligated Uranyl(V) Dioxocations, C. M. Leavitt*, V. S. Bryantsev, W. A. de Jong, M. S. Diallo, W. A. Goddard III, G. S. Groenewold and M. J. Van Stipdonk, J. Phys. Chem. A, 113, 2350-2358 (2009).
  6. 2-Electron 3-Atom Bond in Side-on (η2) Superoxo Complexes: U(IV) and U(V) Dioxo Monocations, V. S. Bryantsev, K. C. Cossel, M. S. Diallo, W. A. Goddard, III, W. A. de Jong, G. S. Groenewold, W. Chien* and M. J. Van Stipdonk, J. Phys. Chem. A, 112, 5777-5780 (2008).
  7. Investigation of Acidity and Nucleophilicity of Diphenyldithiophosphinate Ligands Using Theory and Gas-phase Dissociation Reactions, C. M. Leavitt*, G. L. Gresham, J.-J. Gaumet, D. Peterman, J. Klaehn, M. T. Benson, F. Aubriet, M. J. Van Stipdonk and G. S. Groenewold, Inorg. Chem., 47, 3056-3064 (2008).
  8. Gas-phase Uranyl-Nitrile Complex Ions, M. J. Van Stipdonk, W. Chien*, K. Bulleigh*, Q. Wu and G. S. Groenewold, J. Phys. Chem. A, 110, 959-970 (2006).

Vibrational spectroscopy of gas-phase ions using wavelength-selective Infrared Multiple Photon Photodissociation (IRMPD)

A general limitation of our gas-phase experimental approaches to study intrinsic chemistry is that no direct structural information is produced. Mass spectrometers provide only a mass-to-charge ratio and limited information regarding the connection of atoms. Determinations of structure therefore rely heavily either on chemical intuition or theoretical calculations. To fully explain and understand gas-phase reactivity, more definitive assessments of structure are needed. An ideal source of structural information would be a vibrational spectrum, but collection of a conventional linear absorption is often impracticable because the concentrations of “absorber” ions in the gas phase are too low. A solution to this problem is to use infrared multiple-photon photodissociation (IRMPD), in which an ion of interest is isolated in an ITMS and then irradiated using a tunable infrared wavelength laser. In this “action-spectroscopy” approach, resonant absorption of a photon is followed by intramolecular vibrational energy redistribution, and because radiative cooling is slow, rapid absorption of multiple photons raises the internal energy up to and beyond dissociation thresholds. Using IRMPD, precursor and product ion intensities can be measured as a function of photon wavelength to provide an infrared spectrum.

A decade ago, our group began using IRMPD to produce infrared spectra of a range of gas-phase peptide ions and metal ion complexes. These experiments are conducted at the Free Electron Laser for Infrared eXperiments (FELIX) facility located at Radboud University Nijmegen in The Netherlands. The FELIX free-electron laser is capable of producing a high intensity beam of light that is tunable across the mid-IR region, and is interfaced to a Fourier-transform ion cyclotron resonance, ion-trapping mass spectrometer. Using IRMPD, our group, in collaboration with scientists at the Idaho National Laboratory and the Molecular Dynamics group at FELIX, generated the first infrared spectra of discrete uranyl complex ions, uranyl and europium nitrate anions, and vanadyl complexes. In an example involving peptide ions, IRMPD spectroscopy and DFT calculations were used to characterize the structure of b2+ derived from protonated trialanine. Our results unambiguously show that the b2+ fragment ion from protonated AAA has an oxazolone structure protonated at the oxazolone N-atom. IRMPD spectroscopy is also being applied to characterization of cyclized product ions that lead to scrambling of sequences, and several for which the structure (and therefore formation mechanism) is not currently known. In 2010 and beyond, our ability to determine the structures of gas-phase ions will be significantly improved with the establishment of collaboration with Mark Johnson and his group at Yale University, who specialize on design and use of instrument that allow for tagging of ultra-cold ions for investigation by IR spectroscopy. Work is now underway to add ultraviolet and infrared photodissociation capability to our mass spectrometers at Duquesne.

Representative publications (*indicates an undergraduate student author):

  1. Hiding in Plain Sight: Unmasking the Diffuse Spectral Signatures of the Protonated N-Terminus in Simple Peptides, C. M. Leavitt, A. F. DeBlase, M. van Stipdonk, A. B. McCoy, and M. A. Johnson, J. Phys. Chem. Lett, 4, 3450-3457 (2013)
  2. Isomer-specific IR−IR Double Resonance Spectroscopy of D2-Tagged Protonated Dipeptides Prepared in a Cryogenic Ion Trap, C. M. Leavitt, A. B. Wolk, M. Z. Kamrath, E. Garand, J. A. Fournier, M. J. Van Stipdonk and M. A. Johnson, J. Phys. Chem. Lett. 3, 1099-1105 (2012).
  3. Characterizing the Intramolecular H-bond and Secondary Structure in Methylated GlyGlyH+ with H2 Predissociation Spectroscopy, C. M. Leavitt, A. B. Wolk, M. Z. Kamrath, E. Garand, M. J. Van Stipdonk and M. A. Johnson, J. Am. Soc. Mass Spectrom. 22, 1941-1952 (2011).
  4. Structure of the (M+H-H2O)+ Ion from Tetraglycine: a Revisit by Means of Density Functional Theory and Isotope Labeling, U. Verkek, J. Zhao, M. J. Van Stipdonk, J. Oomens, A. C. Hopkinson and K. W. M. Siu, J. Phys. Chem. A. 115, 6683–6687 (2011)
  5. Vibrational Characterization of Simple Peptides Using Cryogenic Infrared Photodissociation of H2-tagged Mass-selected Ions, M. S. Kamrath, E. Garand, P. A. Jordan, C. M. Leavitt, A. B. Wolk, M. J. Van Stipdonk, S. J. Miller and M. A. Johnson, J. Am. Chem. Soc. 133, 6440-6448 (2011)
  6. Structure and Reactivity of the Cysteine Methyl Ester Radical Cation, R. A, J. O'Hair, S. Osburn, J. D. Steill, J. Oomens, M. Van Stipdonk, V. Ryzhov, Chem. Eur. J., 17, 873–879 (2011).
  7. The Structure of (M+H-H2O)+ Generated from Protonated Tetraglycine Revealed by Tandem MS and IRMPD Spectroscopy, B. Bythell, M. van Stipdonk, R. P. Dain, S. Curtice*, G. S. Groenewold, B. Paizs, J. D. Steill and J. Oomens, J. Phys. Chem. A., 114, 5076-5082 (2010).
  8. Infrared Spectroscopy of Fragments of Protonated Peptides: Direct Evidence for Macro-cyclic Structures of b5 Ions, U. Erlekam, B. J. Bythell, D. Scuderi, M. Van Stipdonk, B. Paizs and P. Maitre, J. Am. Chem. Soc., 131, 11503–11508 (2009).
  9. 9. Vibrational Spectroscopy of Mass Selected [UO2(ligand)n]2+ Complexes in the Gas Phase: Comparison with Theory, G. S. Groenewold, A. K. Gianotto, K. C. Cossel*, M. J. Van Stipdonk, D. T. Moore, N. Polfer, J. Oomens, W. A. de Jong, and L. Visscher, J. Am. Chem. Soc., 128, 4802-4813 (2006).
Courses

Fall 2013: CHEM 423: Analytical Chemistry

This course includes theoretical and practical training of modern methods in chemical analysis with emphasis on instrumental methods.

Spring 2014: CHEM 425R: Advanced Integrated Laboratory

In this course, students work in small teams on real research problems. Each team contributes to a single problem, and several chemical and biochemical problems may be studied over the course of a semester. In the gas-phase chemistry module, students will (a) study ligand addition reactions and ion stability using tandem mass spectrometry and (b) develop better approaches for peptide sequencing using mass spectrometry.

Professional Organizations

American Society for Mass Spectrometry

Metal ions interest group coordinator, 2012-2014

Exposomics interest group coordinator, 2014-2016

American Chemical Society

Editorial boards

Journal of the American Society for Mass Spectrometry

ISRN Spectroscopy

Scholarship

Publications in Peer-reviewed Journals and Conference Proceedings

(aPublication from graduate or post-doctoral work at Texas A&M University; bPublication from Wichita State University; cPublication from Lawrence University; dPublication from Duquesne University. *Undergraduate student author)

  1. Surface Structure Investigations Using Plasma Desorption Mass Spectrometry and Coincidence Countinga, M. J. Van Stipdonk, M. A. Park, E. A. Schweikert, P. Sylvester and A. Clearfield, Int. J. Mass Spectrom. Ion Processes, 128, 133-41 (1993).
  2. On the Formation of Polyatomic Ions from Solid Surfacesa, M. J. Van Stipdonk and E. A. Schweikert, Nucl. Instr. Meth. Phys. Res., B88, 55-60 (1994).
  3. High Energy Chemistry Caused by Fast Ion-Solid Interactionsa, M. J. Van Stipdonk and E. A. Schweikert, Nucl. Instr. Meth. Phys. Res., B96, 530-535 (1995).
  4. Secondary Ion Correlations in Plasma Desorption Mass Spectrometry as a Function of Fission Fragment Energya, W. R. Ferrell, M. J. Van Stipdonk, E. F. da Silveira and E. A. Schweikert, Nucl. Inst. Meth. Phys. Res., B96, 536-540 (1995).
  5. A Mass Spectrometric Method for Probing Surface Structurea, M. J. Van Stipdonk, J. B. Shapiro and E. A. Schweikert, Vacuum, 46, 1227-1230 (1995).
  6. A Plasma Desorption Mass Spectrometry Study of Cluster Ion Formation from Group IIA Nitratesa, W. R. Ferrell, M. J. Van Stipdonk and E. A. Schweikert, Nucl. Inst. Meth. Phys. Res., B112, 55-58 (1996).
  7. The Use of Coincidence Counting Mass Spectrometry to Study the Emission and Metastable Dissociation of Cluster Ionsa, M. J. Van Stipdonk and E. A. Schweikert, Nucl. Inst. Meth. Phys. Res., B112, 68-71 (1996).
  8. Secondary Cluster Ion Distributions Produced by MeV Ion Impacts on Group IIA Oxides and Nitratesa, W. R. Ferrell, S. L. von Heimburg, M. J. Van Stipdonk and E. A. Schweikert, Int. J. Mass Spectrom. Ion Processes, 155, 89-97 (1996).
  9. A Comparison of Desorption Yields from C60+ to Atomic and Polyatomic Projectiles at keV Energiesa, M. J. Van Stipdonk, R. D. Harris and E. A. Schweikert, Rapid Comm. Mass Spectrom., 10, 1987-91 (1996).
  10. Time Correlated Luminescence from MeV Projectile Impactsa, J. F. Blankenship, M. J. Van Stipdonk and E. A. Schweikert, Nucl. Inst. Meth. Phys. Res., B119, 583-86 (1996).
  11. Matrix Effects on the Fragmentation of Vitamin B12 in Plasma Desorption Mass Spectrometrya, J. F. Blankenship, M. J. Van Stipdonk and E. A. Schweikert, Rapid Comm. Mass Spectrom., 11, 143-47 (1997).
  12. Time-of-Flight Secondary Ion Mass Spectrometry of NaBF4: A Comparison of Atomic and Polyatomic Primary Ions and Constant Impact Energya, M. J. Van Stipdonk, R. D. Harris and E. A. Schweikert, Rapid Comm. Mass Spectrom., 11, 1794-1798 (1997).
  13. Tutorial: Coincidence Measurements in Mass Spectrometrya, M. J. Van Stipdonk, E. A. Schweikert and M. A. Park, J. Mass Spectrom., 32, 1151-1161 (1997).
  14. Sublinear Effect in Light Emission from Cesium Iodide Bombarded by keV Polyatomic Projectilesa, K. Baudin, E. S. Parilis, J. F. Blankenship, M. J. Van Stipdonk and E. A. Schweikert, Nucl. Inst. Meth. Phys. Res., B134, 352-359 (1998).
  15. keV Cluster Impacts: Prospects for Cluster-SIMSa, R. D. Harris, M. J. Van Stipdonk and E. A. Schweikert, Int. J. Mass Spectrom. Ion Processes, 174, 167-77 (1998).
  16. Polyatomic Projectiles for the Chemical Characterization of Organics on Surfacesa, R. D. Harris, M. J. Van Stipdonk and E. A. Schweikert, Secondary Ion Mass Spectrometry, SIMS XI Proceedings, 463 (1998).
  17. Comparison of Cs and C60 Primary Projectiles for the Characterization of GaAs and Si Surfacesa, D. R. Justes, R. D. Harris, M. J. Van Stipdonk and E. A. Schweikert, Secondary Ion Mass Spectrometry, SIMS XI Proceedings, 581 (1998).
  18. Chemical Effects in Ion Formation Induced by Polyatomic Ion Impacts on Inorganic Targetsa, R. D. English, R. D. Harris, M. J. Van Stipdonk and E. A. Schweikert, Secondary Ion Mass Spectrometry, SIMS XI Proceedings, 589 (1998).
  19. Carbon Cluster Formation from Organic Targets Examined Using Polyatomic Primary Projectiles in SIMSa, C. W. Diehnelt, M. J. Van Stipdonk, R. D. Harris and E. A. Schweikert, Secondary Ion Mass Spectrometry, SIMS XI Proceedings, 593 (1998).
  20. Secondary Ion Emission from keV Cluster Impactsa, M. J. Van Stipdonk, R. D. Harris and E. A. Schweikert, Secondary Ion Mass Spectrometry, SIMS XI Proceedings, 877 (1998).
  21. Probing Silicon Substitution in Molecular Sieves by Plasma Desorption Mass Spectrometrya, M. J. Van Stipdonk and E. A. Schweikert, J. Mol. Structure, 469, 183-190 (1998).
  22. Recoiled Ions from Polyatomic Cluster Impacts on Organic and Inorganic Targetsa, C. W. Diehnelt, M. J. Van Stipdonk and E. A. Schweikert, Nucl. Inst. Meth. Phys. Res., 142, 606-611 (1998).
  23. A Comparison of Ion Emission from NaNO3 by keV Energy Atomic and Polyatomic Primary Ionsa, M. J. Van Stipdonk, D. R. Justes, V. Santiago and E. A. Schweikert, Rapid Comm. Mass Spectrom., 12, 1639-1643 (1998).
  24. Multi-anode Detection in Electrospray Ionization Time-of-Flight Mass Spectrometrya, D. C. Barbacci, D. H. Russell, J. A. Schultz, J. Holocek, S. Ulrich, W. Burton and M. Van Stipdonk, J. Am. Soc. Mass Spectrom., 9, 1328-1333 (1998).
  25. Carbon Cluster Formation from Polymers Caused by MeV Ion Impacts and keV Cluster Ion Impactsa, C. W. Diehnelt, M. J. Van Stipdonk and E. A. Schweikert, Phys. Rev. A, 59, 4470-4474 (1998).
  26. Negative Secondary Ion Emission from NaBF4: Comparison of Atomic and Polyatomic Projectiles at Different Impact Energiesa, M. J. Van Stipdonk, V. Santiago and E. A. Schweikert, J. Mass Spectrom., 34, 554-562 (1999).
  27. Calcium Phosphate Phase Identification Using XPS and Time-of-Flight Cluster SIMSa, C. C. Chusuei, D. W. Goodman, M. J. Van Stipdonk, D. R. Justes and E. A. Schweikert, Anal. Chem., 71, 149-153 (1999).
  28. Ion-Neutral Correlations from the Dissociation of Metal Oxide Cluster Ions in a Reflectron Time-of-Flight Mass Spectrometera, M. J. Van Stipdonk, D. R. Justes, R. D. English and E. A. Schweikert, J. Mass Spectrom., 34, 677-683 (1999).
  29. Secondary Ion Yields Produced by keV Atomic and Polyatomic Ion Impacts on a Self-assembled Monolayer Surfacea, R. D. Harris, W. S. Baker, M. J. Van Stipdonk, R. M. Crooks and E. A. Schweikert, Rapid Comm. Mass Spectrom., 13, 1374-1380 (1999).
  30. Solid-Liquid Adsorption of Calcium Phosphate on TiO2a, C. C. Chusuei, M. J. Van Stipdonk, D. R. Justes, K. H. Loh, E. A. Schweikert and D. W. Goodman, Langmuir, 15, 7355-7360 (1999).
  31. Sputtering of Tetrafluoro and Tetraphenylborate Anions Adsorbed to an Amine Terminated Self-assembled Monolayer Surfacea, M. J. Van Stipdonk, R. D. English and E. A. Schweikert, J. Phys. Chem. B., 103, 7929-7934 (1999).
  32. Charge Remote Fragmentation of Organic Molecules Exchanged on an Aminoethane Thiolate Self-Assembled Monolayera, C. W. Diehnelt, M. J. Van Stipdonk, R. D. English and E. A. Schweikert, Secondary Ion Mass Spectrometry, SIMS XII Proceedings, 179-182 (2000).
  33. Altering Secondary Ion Internal Energy by Polyatomic Ion Impacta, C. W. Diehnelt, M. J. Van Stipdonk and E. A. Schweikert, Secondary Ion Mass Spectrometry, SIMS XII Proceedings, 267-270 (2000).
  34. Comparison of Secondary Ion Formation from Nitrate Salts Produced by Atomic and Cluster Projectiles at keV and MeV Energiesa, M. J. Van Stipdonk, V. Santiago and E. A. Schweikert, Secondary Ion Mass Spectrometry, SIMS XII Proceedings, 287-290 (2000).
  35. Decay Fractions of Inorganic Cluster Ions Sputtered by Atomic and Polyatomic Primary Ionsa, M. J. Van Stipdonk, V. Santiago and E. A. Schweikert, Secondary Ion Mass Spectrometry, SIMS XII Proceedings, 291-294 (2000).
  36. Optimum Monolayer Oxidation Parameters for Improving Mass Analysisa, R. D. English, M. J. Van Stipdonk and E. A. Schweikert, Secondary Ion Mass Spectrometry, SIMS XII Proceedings, 745-748 (2000).
  37. Alkyl Sulfates Exchanged onto Self-Assembled Monolayer Surfaces: Adsorption Reversibility and Secondary Ion Yield Measurementsa, R. D. English, M. J. Van Stipdonk and E. A. Schweikert, Secondary Ion Mass Spectrometry, SIMS XII Proceedings, 809-812 (2000).
  38. Secondary Ion Emission from keV Energy Atomic and Polyatomic Projectile Impacts on Sodium Iodatea, M. J. Van Stipdonk, V. Santiago, C. C. Chusuei, D. W. Goodman and E. A. Schweikert, Int. J. Mass Spectrom., 197, 149-161 (2000).
  39. On the Speciation of Sodium Nitrate and Nitrite Using keV Energy Atomic and Polyatomic and MeV Energy Atomic Projectiles With Secondary Ion Mass Spectrometrya, M. J. Van Stipdonk, D. R. Justes, C. R. Force, and E. A. Schweikert, Anal. Chem., 72, 2468-2474 (2000).
  40. SIMS of Organic Anions Adsorbed onto an Aminoethanethiol Self-Assembled Monolayer: An Approach for Enhanced Secondary Ion Emissiona, M. J. Van Stipdonk, R. D. English and E. A. Schweikert, Anal. Chem., 72, 2618-2626 (2000).
  41. Secondary Cluster Ion Emission from MeV Ion Impacts on NaBF4: Ion Decay Fractions and Dissociation Pathwaysa, M. J. Van Stipdonk, W. R. Ferrell, D. R. Justes, R. D. English and E. A. Schweikert, Int. J. Mass Spectrom., 202(1-3), 111-119 (2000).
  42. Determination of the Metastable Dissociation Pathways for Chromium/Oxygen Cluster Ions Sputtered From Potassium Chromate and Dichromate Using the Ion-Neutral Correlation Methoda, M. J. Van Stipdonk, D. R. Justes and E. A. Schweikert, Int. J. Mass Spectrom., 203 (1-3), 59-69 (2000).
  43. Characterization of Photooxidized Self Assembled Monolayers and Bilayers By Spontaneous Desorption Mass Spectrometrya, R. D. English, M. J. Van Stipdonk, R. Sabapathy, R. M. Crooks and E. A. Schweikert, Anal. Chem., 72, 5973-5980 (2000).
  44. Production, Dissociation and Gas Phase Stability of Sodium Fluoride Cluster Ions Studied Using ESI-Ion Trap Mass Spectrometryb, M. P. Ince, B. A. Perera and M. J. Van Stipdonk, Int. J. Mass Spectrom., 207, 41-55 (2000).
  45. Influence of Constituent Mass on Secondary Ion Yield Enhancements from Polyatomic Ion Impacts on Aminoethanethiol Self-assembled Monolayer Surfacesa, R. D. English, M. J. Van Stipdonk, C. W. Diehnelt and E. A. Schwiekert, Rapid Comm. Mass Spectrom., 15, 370-372 (2001).
  46. Effectiveness of Atomic and Polyatomic Primary Ions For Organic Secondary Ion Mass Spectrometrya, C. W. Diehnelt, M. J. Van Stipdonk and E. A. Schweikert, Int. J. Mass Spectrom., 207, 111-122 (2001).
  47. Gas Phase Attachment of Water and Methanol to Ag+ Complexes with α-Amino Acids in an Ion Trap Mass Spectrometerb, B. A. Perera, M. P. Ince, E. R. Talaty and M. J. Van Stipdonk, Rapid Comm. Mass Spectrom., 15(8), 615-622 (2001).
  48. Dihydrobis(4-cyano-3-phenylpyrazol-1-yl)borate: Homoleptic Mononuclear Complexes with a Cyano-substituted Scorpionate Ligandb, C. J. Siemer, J. Goswami, P. Kahol, M. J. Van Stipdonk and D. M. Eichhorn, Inorg. Chem., 40, 4081-4084 (2001).
  49. Elucidation of The Fragmentation Pathways for the Collision Induced Dissociation of the Binary Ag(I) Complex With Phenylalanineb, E. R. Talaty, B. A. Perera, A. L. Gallardo*, J. M. Barr* and M. J. Van Stipdonk, J. Phys. Chem. A, 105, 8059-8068 (2001).
  50. Secondary Ion Yield Improvements for Phosphated and Sulfated Molecules Using Substrate-Enhanced Time-of-Flight Secondary Ion Mass Spectrometrya, R. D. English, M. J. Van Stipdonk and E.A. Schweikert, Int. J. Mass Spectrom., 209, 113-124 (2001).
  51. Spectroscopic, Electrochemical and Photochemical Studies of Self-assembled via Axial Coordination Zinc Porphyrin-Fulleropyrrolidine Dyadsb, F. D'Souza, G. R. Deviprasad, M. E. Zandler, V. T. Huang, K. Arkady, M. Van Stipdonk, A. Perera, M. E. El-Khouly, M. Fujitsuka and O. Ito, J. Phys. Chem. A, 106 3243-3252 (2002).
  52. Determination of Regioselectivity in Ring-opening of tert-butylaziridinones by a Combination of 15N Labeling And Electrospray Ionization-Ion Trap Mass Spectrometryb, E. R. Talaty, M. J. Van Stipdonk and M. J. Hague*, J. Mass Spectrom., 37, 31-40 (2002).
  53. Influence of a Ring Constituent on the Tendency to Form H2O Adducts to Ag+ Complexes with Phenylalanine-Analogues In An Ion Trap Mass Spectrometerb, B. A. Perera, A. L. Gallardo*, J. M. Barr* and M. J. Van Stipdonk, J. Mass Spectrom., 37, 401-413 (2002).
  54. Gas Phase Cluster Ions Derived Sodium and Potassium Tetrafluoroborate and Their Collision Induced Dissociation in an Ion Trap Mass Spectrometerb, M. P. Ince, B. P. Perera, J. A. Martin* and M. J. Van Stipdonk, Rapid Comm. Mass Spectrom., 16, 355-363 (2002).
  55. Multi-stage Tandem Mass Spectrometry of Metal Cationized Leucine Enkephalin and Leucine Enkephalin Amide, J. M. Barr* and M. J. Van Stipdonkb, Rapid Comm. Mass Spectrom., 16, 566-578 (2002).
  56. Formation of [bn+17+Ag)+ Product Ions from Ag+ Cationized Native and Acetylated Peptidesb, V. Anbalagan, B. A. Perera, A.T. M. Silva, A. L. Gallardo*, M. Barber*, J. M. Barr*, S. M. Tekarli*, E. R. Talaty and M. J. Van Stipdonk, J. Mass Spectrom., 37, 910-926 (2002).
  57. Coincidence Experiments in Desorption Mass Spectrometrya, C. W. Diehnelt, R. D. English, M. J. Van Stipdonk and E. A. Schweikert, Nucl. Inst. Meth. Phys. Res., B193, 883-890 (2002).
  58. Formation of an Ethylene-bridged bis(benzisothiazole) Dication by Oxidative Decomplexation of Ni(tsalen) with FeCl3b, N. Goswami, M. J. Van Stipdonk and D. M. Eichhorn, Inorg. Chem. Comm., 6, 86-89 (2003).
  59. McLafferty-type Rearrangement in the Collision Induced Dissociation of Li+, Na+ and Ag+ Cationized Esters of N-acetylated Peptidesb, V. Anbalagan, G. Niyakorn*, J. Patel* and M. J. Van Stipdonk, Rapid Comm. Mass Spectrom., 17, 291-300 (2003).
  60. Gas-phase Investigation of Pd(II)-Alanine Complexes with Small Histidine Containing Peptidesb, V. Anbalagan and M. J. Van Stipdonk, J. Mass Spectrom., 38, 982-989 (2003).
  61. Gas-Phase Hydration and Alcohol Addition Reactions of Complexes Composed of Ag+ and a Single Alcohol Moleculeb, D. Hanna, M. Silva, J. Morrison*, S. Tekarli*, V. Anbalagan and M. Van Stipdonk, J. Phys. Chem. A 107, 5528-5537 (2003).
  62. Gas-phase Hydration of U(IV), U(V) and U(VI) Oxo Cationsb, G. L. Gresham, A. K. Gianotto, P. B. Harrington, L. Cao, J. R. Scott, J. E. Olson, A. D. Appelhans, M. J. Van Stipdonk and G. S. Groenewold, J. Phys. Chem. A, 107, 8530-8538 (2003).
  63. Elucidation of the Collision-induced Dissociation Pathways of Water and Alcohol Coordinated Complexes Containing the Uranyl Cationb, M. Van Stipdonk, G. Gresham, G. Groenewold, V. Anbalagan, D. Hanna and W. Chien*,, J. Am. Soc. Mass Spectrom., 14, 1205-1214 (2003).
  64. Influence of "Alternative" C-terminal Amino Acids on the Formation of (b3+17+Cat)+ Products from Metal Cationized Synthetic Tetrapeptidesb, V. Anbalagan, S. Rajagopalachary*, K. Bulleigh*, A. T. M. Silva, B. A. Perera, E. R. Talaty and M. J. Van Stipdonk, J. Mass Spectrom., 39, 495-504 (2004).
  65. A Coordination Polymer from a Cyanoscorpionate Complexb, C. J. Siemer, M. J. Van Stipdonk, P. K. Kahol, and D. M. Eichhorn, Polyhedron, 23, 235-238 (2004).
  66. Intrinsic Hydration of Uranyl-Hydroxide, -Nitrate and -Acetate Complexesb, W. Chien*, D. Hanna, V. Anbalagan, G. Gresham, G. Groenewold, M. Zandler and M. J. Van Stipdonk, J. Am. Soc. Mass Spectrom., 15, 777-783 (2004).
  67. CID MS/MS of Desferrioxamine Siderphore Complexes from ESI of UO22+, Fe3+ and Ca2+ Solutionsb, G. S. Groenewold, M. J. Van Stipdonk, G. L. Gresham, W. Chien, K. Bulleigh* and A. Howard*, J. Mass Spectrom., 39, 752-761 (2004).
  68. Mechanism-based Inactivation of Human Leukocyte Elastase Via an Enzyme-Induced Sulfonamide Fragmentation Process,b L. Wei, X. Gan, K. R. Alliston, J. Zhong, J. Tu, A. B. Perera, M. Van Stpdonk and W. C. Groutas, Arch. Biochem. Biophys., 429, 60-70 (2004).
  69. Oxidation of 2-Propanol Ligands Following Collision-induced Dissociation of a Gas-phase Uranyl Complexb, M. J. Van Stipdonk, W. Chien, V. Anbalagan, G. L. Gresham and G. S. Groenewold, Int. J. Mass Spectrom., 237, 175-183 (2004).
  70. Gas-phase Complexes Containing the Uranyl Ion and Acetoneb, M. J. Van Stipdonk, W. Chien, V. Anbalagan, K. Bulleigh*, D. Hanna and G. S. Groenewold, J. Phys. Chem. A, 108, 10448-10457 (2004).
  71. Production and Collision-Induced Dissociation of Gas-Phase, Water and Alcohol Coordinated Uranyl Complexes Containing Halide or Perchlorate Anionsb, V. Anbalagan, W. Chien, G. L. Gresham, G. S. Groenewold and M. J. Van Stipdonk, Rapid Comm. Mass Spectrom., 18, 3028-3034 (2004).
  72. Novel Fragmentation Pathway for CID of (bn-1+Cat)+ Ions From Model, Metal Cationized Peptidesb, T. J. Cooper, E. R. Talaty and M. J. Van Stipdonk, J. Am. Soc. Mass Spectrom., 16, 1305-1310 (2005).
  73. Investigation of Intra-molecular Proton Migration in A Series of Model, Metal-Cationized Tripeptides Using In-Situ Generation of an Isotope Labelb, K. Bulleigh*, A. Howard*, T. Do*, Q. Wu, V. Anbalagan and M. Van Stipdonk, Rapid Comm. Mass Spectrom., 20, 227-232 (2006).
  74. Binding of Molecular O2 to Di- and Tri-Ligated [UO2]+ b, G. S. Groenewold, K. C. Cossel, G. L. Gresham, A. K. Gianotto, A. D. Appelhans, J. E. Olson, M. J. Van Stipdonk, and W. Chien, J. Am. Chem. Soc., 128, 3075-3084 (2006).
  75. Gas-phase Uranyl-Nitrile Complex Ionsb, M. J. Van Stipdonk, W. Chien*, K. Bulleigh*, Q. Wu and G. S. Groenewold, J. Phys. Chem. A, 110, 959-970 (2006).
  76. Vibrational Spectroscopy of Mass Selected [UO2(ligand)n]2+ Complexes in the Gas Phase: Comparison with Theoryb, G. S. Groenewold, A. K. Gianotto, K. C. Cossel, M. J. Van Stipdonk, D. T. Moore, N. Polfer, J. Oomens, W. A. de Jong, and L. Visscher, J. Am. Chem. Soc., 128, 4802-4813 (2006).
  77. Isotope Labeling and Theoretical Study of the Formation of a3* Ions from Protonated Tetraglycineb, T. J. Cooper, E. Talaty, J. Grove*, S. Suhai, B. Paizs and M. J. Van Stipdonk, J. Am. Soc. Mass Spectrom., 17, 1654-1664 (2006).
  78. Transfer of Hydrogen from an α-Carbon Position during Formation of a Sequence Ion By Collision-induced Dissociationb, S. Osburn* and M. J. Van Stipdonk, J. Undergrad. Res. Chem., 3, 105-109 (2006).
  79. A Study of the Elimination of Water from Lithium-cationized Tripeptide Methyl Esters by Means of Tandem Mass Spectrometry and Isotope Labelingb, E. R. Talaty, T. J. Cooper, D. L. Piland*, D. J. Bateman*, A. Syed*, W. Stevenson* and M. J. Van Stipdonk, Rapid Comm. Mass Spectrom., 20, 3007-3017 (2006).
  80. Generation of Gas-phase VO2+, VOOH+ and VO2+-Nitrile Complex Ions by Electrospray Ionization and Collision-induced Dissociationb, Z. Parsons*, C. Leavitt*, T. Duong*, G. S. Groenewold, G. L. Gresham and M. J. Van Stipdonk, J. Phys. Chem. A, 110, 11627-11635 (2006).
  81. Collision-induced dissociation of Protonated Tetrapeptides Containing β-Alanine, β-Aminobutyric Acid, γ-Aminocaproic Acid or 4-Aminomethylbenzoic Acid Residuesb, E. R. Talaty, T. J. Cooper, S. M. Osburn* and M. J. Van Stipdonk, Rapid Comm. Mass Spectrom., 20, 3443-3455 (2006).
  82. Mid-infrared Vibrational Spectra of Gas-phase, Acetone Ligated Cerium Hydroxide Cationb, G. S. Groenewold, A. K. Gianotto, K. C. Cossel, M. J. Van Stipdonk, J. Oomens, N. Polfer, D. T. Moore and W. A. de Jong, Phys. Chem.-Chem. Phys., 9, 596-606 (2007).
  83. Synthesis and Crystal Structures of 3-tert-butyl-4-cyano Pyrazole and its Complexes with Cobalt(II), Manganese(II) and Copper(II) b, N. Zhao, M. Van Stipdonk and D. Eichhorn, Polyhedron, 26, 2449-2454 (2007).
  84. Investigation of the Neutral Loss of a Full Amino Acid Mass During CID of b3+ Ion Derived from a Model Peptide Containing a 4-aminobutyric Acid Residueb, E. R. Talaty, C. Chueachavalit*, S. Osburn* and M. J. Van Stipdonk, Rapid Comm. Mass Spectrom., 21, 2529-2537 (2007).
  85. Incorporation of Thiolate Donation Using 2,2'-dithiobenzaldehyde: Complexes of a Pentadentate N2S3 Ligand With Relevance to the Active Site of Co Nitrile Hydrataseb, B. W. Smucker, M. J. Van Stipdonk and D. M. Eichhorn, J. Inorg. Biochem., 101, 1537-1542 (2007).
  86. Influence of a 4-aminomethylbenzoic acid Residue on Competitive Fragmentation Pathways During CID of Metal Cationized Peptidesb, S. Osburn*, S. Ochola, E. Talaty and M. Van Stipdonk, Rapid Comm. Mass Spectrom., 21, 3409-3419 (2007).
  87. Sandwich Compounds of Cyanotrispyrazolylborates - Complexation-induced Ligand Isomerization, N. Zhao, M. J. Van Stipdonk, C. Bauer, C. Campana and D. M. Eichhorn, Inorg. Chem., 46, 8662-8667 (2007).
  88. Infrared Spectroscopy of Discrete Uranyl Anion Complexesb, G. S. Groenewold, A. K. Gianotto, M. E. McIlwain, M. J. Van Stipdonk, M. Kullman, D. T. Moore, N. Polfer and J. Oomens, J. Phys. Chem. A, 112, 508-521 (2008).
  89. Vibrational Spectroscopy of Anionic Nitrate Complexes of UO22+ and Eu3+ Isolated in the Gas Phaseb, G. S. Groenewold, J. Oomens, W. A. de Jong, G. L. Gresham, M. E. McIlwain and M. J. Van Stipdonk, Phys. Chem.-Chem. Phys., 10, 1192-1202 (2008).
  90. Investigation of Acidity and Nucleophilicity of Diphenyldithiophosphinate Ligands Using Theory and Gas-phase Dissociation Reactionsb, C. M. Leavitt*, G. L. Gresham, J.-J. Gaumet, D. Peterman, J. Klaehn, M. T. Benson, F. Aubriet, M. J. Van Stipdonk and G. S. Groenewold, Inorg. Chem., 47, 3056-3064 (2008).
  91. Infrared Multiple-photon Photodissociation of Gas-phase Group II Metal-nitrate Anionsb, J. Oomens, L. Myers*, R. P. Dain*, C. M. Leavitt*, V. Pham*, G. Gresham, G. Groenewold and M. J. Van Stipdonk, Int. J. Mass Spectrom., 273, 24-30 (2008).
  92. Spectroscopic Investigation of H Atom Transfer in a Gas-phase Dissociation Reaction: McLafferty Rearrangement of Model Gas-phase Peptide Ionsb, M. J. Van Stipdonk, D. R. Kerstetter, C. M. Leavitt*, G. S. Groenewold, J. D. Steill and J. Oomens, Phys. Chem.-Chem. Phys., 10, 3209-3221 (2008).
  93. Generation and Collision-induced Dissociation of Ammonium Tetrafluoroborate Cluster Ionsb, R. P. Dain* and M. J. Van Stipdonk, Rapid Comm. Mass Spectrom., 22, 2044-2052 (2008).
  94. Infrared Spectroscopy of Dioxouranium(V) Complexes with Solvent Molecules: Effect of Reductionb, G. S. Groenewold, G. L. Gresham, M. E. McIlwain, M. J. Van Stipdonk, M. Kullman, J. Oomens, N. Polfer, I. Infante, L. Visscher and W. A. de Jong, ChemPhysChem, 9, 1278-1285 (2008).
  95. Cyanoscorpionates - Synthesis and Crystallographic Characterization of 1-D Cu(I) Coordination Polymersb, N. Zhao, J. C. Bullinger, M. J. Van Stipdonk, C. L. Stern and D. M. Eichhorn, Inorg. Chem., 47, 5945-5950 (2008).
  96. 2-Electron 3-Atom Bond in Side-on (η2) Superoxo Complexes: U(IV) and U(V) Dioxo Monocationsb, V. S. Bryantsev, K. C. Cossel, M. S. Diallo, W. A. Goddard, III, W. A. de Jong, G. S. Groenewold, W. Chien and M. J. Van Stipdonk, J. Phys. Chem. A, 112, 5777-5780 (2008).
  97. Computational Investigation of Group I Metal-Chlorate Ion Pairs and Their Monohydratesb, R. P. Dain* and M. J. Van Stipdonk, J. Mol. Structure/THEOCHEM, 868, 42-49 (2008).
  98. Formation of (b3-1+cat)+ Ions from Metal-cationized Tetrapeptides Containing β-alanine, γ-aminobutyric acid or ε-aminocaproic Acid Residuesb, S. M. Osburn*, S. O. Ochola, E. R. Talaty and M. J. Van Stipdonk, J. Mass Spectrom., 43, 1458-1469 (2008).
  99. Focus Issue on Peptide Fragmentationb, B. Paizs and M. J. Van Stipdonk, J. Am. Soc. Mass Spectrom., 19, 1717-1718 (2008).
  100. Structure and Reactivity of an and an* Ions Investigated Using Isotope labeling, Tandem Mass Spectrometry and Density Functional Theory Calculationsb, B. Bythell, S. Molesworth, S. Osburn*, T. Cooper, B. Paizs and M. Van Stipdonk, J. Am. Soc. Mass Spectrom., 19, 1788-1798 (2008).
  101. Sequence Scrambling Fragmentation Pathways of Protonated Peptidesb, C. Bleiholder, S. M. Osburn*, T. D. Williams, S. Suhai, M. J. Van Stipdonk, A. Harrison and B. Paizs, J. Am. Chem. Soc., 130, 17774-17789 (2008).
  102. Spectroscopic Evidence for an Oxazolone Structure of the b2 Fragment Ion From Protonated Tri-alanineb, J. Oomens, S. Young*, S. Molesworth and M. van Stipdonk, J. Am. Soc. Mass Spectrom., 20, 334-339 (2009).
  103. Iron and Cobalt Complexes of 2,6-Diacetylpyridine-bis(R-thiosemicarbazone) (R=H, phenyl) Showing Unprecedented Ligand Deviation from Planarityb, A. Panja, C. Campana, C. Leavitt*, M. J. Van Stipdonk and D. M. Eichhorn, Inorg. Chim. Acta, 362, 1348-1354 (2009).
  104. Addition of H2O and O2 to Acetone and Dimethylsulfoxide Ligated Uranyl(V) Dioxocationsb, C. M. Leavitt*, V. S. Bryantsev, W. A. de Jong, M. S. Diallo, W. A. Goddard III, G. S. Groenewold and M. J. Van Stipdonk, J. Phys. Chem. A, 113, 2350-2358 (2009).
  105. IRMPD Spectroscopy of Anionic Group II Metal Nitrate Clustersb, C. M. Leavitt*, J. Oomens, R. P. Dain*, J. D. Steill, G. S. Groenewold and M. J. Van Stipdonk, J. Am. Soc. Mass Spectrom., 20, 722-782 (2009).
  106. Cerium Oxyhydroxide Clusters: Formation, Structure and Reactivity, F. Aubriet, J.-J. Gaumet, W. A. de Jong, G. S. Groenewold, A. K. Gianotto, M. E. McIlwain, M. J. Van Stipdonk and C. M. Leavitt*, J. Phys. Chem. A., 113, 6239-6252 (2009).
  107. IRMPD Spectroscopy of Potassium-cationized Triethylphosphateb, M. J. van Stipdonk, C. M. Leavitt*, J. Oomens, J. Steill and G. S. Groenewold, Rapid Comm. Mass Spectrom., 23, 2706-2710 (2009).
  108. Infrared Spectroscopy of Fragments of Protonated Peptides: Direct Evidence for Macro-cyclic Structures of b5 Ionsb, U. Erlekam, B. J. Bythell, D. Scuderi, M. Van Stipdonk, B. Paizs and P. Maitre, J. Am. Chem. Soc., 131, 11503-11508 (2009).
  109. Spectroscopic Evidence for Mobilization of Amide Position Protons During CID of Peptide Ionsb, S. Molesworth, C. M. Leavitt*, G. S. Groenewold, J. Oomens, J. Steill and M. van Stipdonk, J. Am. Soc. Mass Spectrom., 20, 1841-1845 (2009).
  110. Influence of Size on Apparent Scrambling of Sequence During CID OF b-Type Ionsb, S. Molesworth, S. M. Osburn* and M. Van Stipdonk, J. Am. Soc. Mass Spectrom, 20, 2174-2181 (2009).
  111. IRMPD Spectroscopy of Gas-phase Sodium and Potassium Chlorate Anionsb, R. P. Dain, C. M. Leavitt*, J. Oomens, J. D. Steill, Gary S. Groenewold and M. J. Van Stipdonk, Rapid Comm. Mass Spectrom., 24, 232-238 (2010).
  112. The Structure of (M+H-H2O)+ Generated from Protonated Tetraglycine Revealted by Tandem MS and IRMPD Spectroscopyb, B. Bythell, M. van Stipdonk, R. P. Dain, G. S. Groenewold, B. Paizs, J. D. Steill and J. Oomens, J. Phys. Chem. A., 114, 5076-5082 (2010).
  113. Variable Denticity in Carboxylate Binding to the Uranyl Dicationb, G. S. Groenewold, W. A de Jong, J. Oomens and M. van Stipdonk, J. Am. Soc. Mass Spectrom. 21, 719-727 (2010).
  114. Influence of Amino Acid Side Chains on Apparent Selective Opening of Cyclic b5 Ionsb, S. Molesworth, S. Osburn* and M. Van Stipdonk, J. Am. Soc. Mass Spectrom. 21, 1028-1036 (2010).
  115. Apparent Inhibition by Arginine of Macrocyclic b Ion Formations from Singly Charged Protonated Peptidesb, S. Molesworth and M. J. van Stipdonk, J. Am. Soc. Mass Spectrom., 21, 1322-1328 (2010).
  116. Vibrational Spectra of Discrete UO22+ Halide Complexes in the Gas Phaseb, G. S. Groenewold, M. J. van Stipdonk, J. Oomens, W. de Jong, G. L. Gresham, M. E. McIlwain, Int. J. Mass Spectrom., 297, 67-75 (2010).
  117. Structure and Reactivity of the Cysteine Methyl Ester Radical Cationb, R. A. J. O'Hair, S. Osburn, J. D. Steill, J. Oomens, M. Van Stipdonk, V. Ryzhov, Chem. Eur. J., 17, 873-879 (2011).
  118. Vibrational Characterization of Simple Peptides Using Cryogenic Infrared Photodissociation of H2-tagged Mass-selected Ionsb, M. S. Kamrath, E. Garand, P. A. Jordan, C. M. Leavitt, A. B. Wolk, M. J. Van Stipdonk, S. J. Miller and M. A. Johnson, J. Am. Chem. Soc. 133, 6440-6448 (2011).
  119. A Study of Fragmentation of Protonated Amides of Some Acylated Amino Acids by Tandem Mass Spectrometry: Observation of an Unusual Nitrilium Ionb, E. R. Talaty, S. M. Young, R. P. Dain and M. J. Van Stipdonk, Rapid Comm. Mass Spectrom. 25, 1119-1129 (2011).
  120. Investigation of Uranyl Nitrate Ion Pairs Complexed with Amide Ligands using Electrospray Ionization Ion Trap Mass Spectrometry and Density Functional Theoryb, G. Gresham, A. Dinescu, M. Benson, M. Van Stipdonk, G. Groenewold, J. Phys. Chem. A. 115, 3497-3508 (2011).
  121. IRMPD Spectroscopy of Group II Cation Complexes with Salicylateb, M. J. Van Stipdonk, R. P. Dain, J. D. Steill, J. Oomens, G. S. Groenewold and M. J. Van Stipdonk, Rapid Comm. Mass Spectrom., 25, 1837-1846 (2011).
  122. Tridendate N2S Ligand from 2,2'-dithiobenzaldehyde and N,N-dimethylethylendiamine: Synthesis, Structure and Characterization of a Ni(II) Complex with Relevance to Ni Superoxide Dismutaseb, J. R. Zimmerman, B. W. Smucker, R. P. Dain, M. J. Van Stipdonk and D. M. Eichhorn, Inorg. Chim. Acta, 373, 54-61 (2011).
  123. Gas-Phase Coordination Complexes of Dipositive Plutonyl, PuVIO22+: Chemical Diversity across the Actinyl Seriesb, D. Rios, P. Rutkowski, M. Van Stipdonk and J. Gibson, Inorg. Chem., 50, 4781-4790 (2011).
  124. Structure of the (M+H-H2O)+ Ion from Tetraglycine: a Revisit by Means of Density Functional Theory and Isotope Labelingb, U. Verkek, J. Zhao, M. J. Van Stipdonk, J. Oomens, A. C. Hopkinson and K. W. M. Siu, J. Phys. Chem. A. 115, 6683-6687 (2011).
  125. The Gas-phase bis-Uranyl Nitrate Complex [(UO2)2(NO3)5]-: Infrared Spectrum and Structureb, G. S. Groenewold, M. J. van Stipdonk, J. Oomens, W. A. de Jong and M. E. McIlwain, Int. J. Mass Spectrom. Special issue in honor of John Eyler 308, 175-180 (2011).
  126. Gas-phase Coordination Complexes of UVIO22+, NpVIO22+ and PuVIO22+ with Dimethylformamideb, P. X. Rutkowski, D. Rios, J. K. Gibson and M. J. Van Stipdonk, J. Am. Soc. Mass Spectrom. 22, 2042-2048 (2011).
  127. Characterizing the Intramolecular H-bond and Secondary Structure in Methylated GlyGlyH+ with H2 Predissociation Spectroscopyb, C. M. Leavitt, A. B. Wolk, M. Z. Kamrath, E. Garand, M. J. Van Stipdonk and M. A. Johnson, J. Am. Soc. Mass Spectrom. 22, 1941-1952 (2011).
  128. On the Formation of Hypercoordinated Uranyl Complexesb, G. Schoendorff, W. A. de Jong, M. J. Van Stipdonk, J. K. Gibson, M. S. Gordon, T. L. Windus, Inorg. Chem. 50, 8490-8493 (2011).
  129. IRMPD Spectroscopy of b2 Ions From Protonated Tripeptides with 4-aminomethylbenzoic acid Residuesb, M. J. Kullman, S. Molesworth, G. Berden, J. Oomens and M. J. Van Stipdonk, Int. J. Mass Spectrom., 316-318, 174-181 (2012).
  130. Isomer-specific IR-IR Double Resonance Spectroscopy of D2-Tagged Protonated Dipeptides Prepared in a Cryogenic Ion Trapc, C. M. Leavitt, A. B. Wolk, M. Z. Kamrath, E. Garand, J. A. Fournier, M. J. Van Stipdonk and M. A. Johnson, J. Phys. Chem. Lett. 3, 1099-1105 (2012).
  131. IRMPD and DFT Study of the Elimination of Water From Protonated 2-Hydroxynicotinic Acidc, M. van Stipdonk, M. J. Kullman, G. Berden and J. Oomens, Int. J. Mass Spectrom., Special issue in honor of Peter Armentrout 330-332 , 134-143 (2012).
  132. The roles of Diacetone Alcohol and Acetone in the Coordination and Dissociation Reactions of Uranyl Complexesc, D. Rios, G. Schoendorff, M. J. Van Stipdonk, M. S. Gordon, T. L. Windus, J. K. Gibson and W. A. de Jong, Inorg. Chem. 51, 12768-12775 (2012).
  133. IRMPD Spectroscopy of Group I and Group II Metal Complexes with Boc-hydroxylamineb, R. P. Dain, G. Gresham, G. S. Groenewold, J. D. Steill, J. Oomens and M. J. van Stipdonk, Rapid Comm. Mass Spectrom., 16, 1867-1872 (2013).
  134. Hiding in Plain Sight: Unmasking the Diffuse Spectral Signatures of the Protonated N-Terminus in Simple Peptidesd, C. M. Leavitt, A. F. DeBlase, M. van Stipdonk, A. B. McCoy, and M. A. Johnson, J. Phys. Chem. Lett, 4, 3450-3457 (2013).
  135. IRMPD Spectroscopy of Deprotonated 6-hydroxynicotinic Acidd, M. J. van Stipdonk, M. J. Kullman, G. Berden and J. Oomens, Rapid Comm. Mass Spectrom. (2014) in press.