Abstract
Hydrated divalent magnesium and calcium clusters are used as nanocalorimeters to measure the internal energy deposited into size-selected clusters upon capture of a thermally generated electron. The infrared radiation emitted from the cell and vacuum chamber surfaces as well as from the heated cathode results in some activation of these clusters, but this activation is minimal. No measurable excitation due to inelastic collisions occurs with the low-energy electrons used under these conditions. Two different dissociation pathways are observed for the divalent clusters that capture an electron: loss of water molecules (Pathway I) and loss of an H atom and water molecules (Pathway II). For Ca(H2O) 2+ n , Pathway I occurs exclusively for n ≥ 30 whereas Pathway II occurs exclusively for n ≤ 22 with a sharp transition in the branching ratio for these two processes that occurs for n ≈ 24. The number of water molecules lost by both pathways increases with increasing cluster size reaching a broad maximum between n = 23 and 32, and then decreases for larger clusters. From the number of water molecules that are lost from the reduced cluster, the average and maximum possible internal energy is determined to be ∼ and 5.2 eV, respectively, for Ca(H2O) 2+30 . This value is approximately the same as the calculated ionization energies of M(H2O) + n , M = Mg and Ca, for large n indicating that the vast majority of the recombination energy is partitioned into internal modes of the ion and that the dissociation of these ions is statistical. For smaller clusters, estimates of the dissociation energies for the loss of H and of water molecules are obtained from theory. For Mg(H2O) 2+ n , n = 4−6, the average internal energy deposition is estimated to be 4.2−4.6 eV. The maximum possible energy deposited into the n = 5 cluster is <7.1 eV, which is significantly less than the calculated recombination energy for this cluster. There does not appear to be a significant trend in the internal energy deposition with cluster size whereas the recombination energy is calculated to increase significantly for clusters with fewer than 10 water molecules. These, and other results, indicate that the dissociation of these smaller clusters is nonergodic.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Wang, H.; Qian, W.; Chin, M. H.; Petyuk, V. A.; Barry, R. C.; Liu, T.; Gritsenko, M. A.; Mottaz, H. M.; Moore, R. J.; Camp, D. G., II; Khan, A. H.; Smith, D. J.; Smith, R. D. Characterization of the mouse brain proteome using global proteomic analysis complemented with cysteinyl peptide enrichment. J. Proteome Res. 2006, 5, 361–369.
Valentine, S. J.; Kulchania, M.; Barnes, C. A. S.; Clemmer, D. E. Multidimensional separations of complex peptide mixtures: A combined high-performance liquid chromatography/ion mobility/time-of-flight mass spectrometry approach. Int. J. Mass Spectrom. 2001, 212, 97–109.
Valentine, S. J.; Liu, X. Y.; Plasencia, M. D.; Hilderbrand, A. E.; Kurulugama, R. T.; Koeniger, S. L.; Clemmer, D. E. Developing liquid chromatography ion mobility mass spectrometry techniques. Expert Rev. Proteomics 2005, 2, 553–565.
Taraszka, J. A.; Kurulugama, R.; Sowell, R. A.; Valentine, S. J.; Koeniger, S. L.; Arnold, R. J.; Miller, D. F.; Kaufman, T. C.; Clemmer, D. E. Mapping the proteome of drosophila melanogaster: Analysis of embryos and adult heads by LC-IMS-MS methods. J. Proteome Res. 2005, 4, 1223–1237.
Han, X. M.; Jin, M.; Breuker, K.; McLafferty, F. W. Extending top-down mass spectrometry to proteins with masses greater than 200 kDa. Science 2006, 314, 109–112.
Ge, Y.; Lawhorn, B. G.; ElNaggar, M.; Strauss, E.; Park, J. H.; Begley, T. P.; McLafferty, F. W. Top down characterization of larger proteins (45 kDa) by electron capture dissociation mass spectrometry. J. Am. Chem. Soc. 2002, 124, 672–678.
Zubarev, R. A.; Kelleher, N. L.; McLafferty, F. W. Electron capture dissociation of multiply charged protein cations: A nonergodic process. J. Am. Chem. Soc. 1998, 120, 3265–3266.
Zubarev, R. A.; Horn, D. M.; Fridriksson, E. K.; Kelleher, N. L.; Kruger, N. A.; Lewis, M. A.; Carpenter, B. K.; McLafferty, F. W. Electron capture dissociation for structural characterization of multiply charged protein cations. Anal. Chem. 2000, 72, 563–573.
Breuker, K.; Oh, H. B.; Horn, D. M.; Cerda, B. A.; McLafferty, F. W. Detailed unfolding and folding of gaseous ubiquitin ions characterized by electron capture dissociation. J. Am. Chem. Soc. 2002, 124, 6407–6420.
Coon, J. J.; Shabanowitz, J.; Hunt, D. F.; Syka, J. E. P. Electron transfer dissociation of peptide anions. J. Am. Soc. Mass Spectrom. 2005, 16, 880–882.
Syka, J. E. P.; Coon, J. J.; Schroeder, M. J.; Shabanowitz, J.; Hunt, D. F. Peptide and protein sequence analysis by electron transfer dissociation mass spectrometry. Proc. Natl. Acad. Sci. U.S.A. 2004, 101, 9528–9533.
Hvelplund, P.; Liu, B.; Nielsen, S. B.; Tomita, S. Electron capture induced dissociation of peptide dications. Int. J. Mass Spectrom. 2003, 225, 83–87.
Hvelplund, P.; Liu, B.; Nielsen, S. B.; Tomita, S.; Cederquist, H.; Jensen, J.; Schmidt, H. T.; Zettergren, H. Electron capture and loss by protonated peptides and proteins in collisions with C-60 and Na. Eur Phys. J. D. 2003, 22, 75–79.
Zubarev, R. A. Reactions of polypeptide ions with electrons in the gas phase. Mass Spectrom. Rev. 2003, 22, 57–77.
Zubarev, R. A.; Haselmann, K. F.; Budnik, B.; Kjeldsen, F.; Jensen, F. Towards an understanding of the mechanism of electron-capture dissociation: A historical perspective and modern ideas. Eur. J. Mass Spectrom. 2002, 8, 337–349.
Zubarev, R. A. Electron-capture dissociation tandem mass spectrometry. Curr. Opin. Biotechnol. 2004, 15, 12–16.
Cooper, H. J.; Hakansson, K.; Marshall, A. G. The role of electron capture dissociation in biomolecular analysis. Mass Spectrom. Rev. 2005, 24, 201–222.
Breuker, K.; Oh, H. B.; Lin, C.; Carpenter, B. K.; McLafferty, F. W. Nonergodic and conformational control of the electron capture dissociation of protein cations. Proc. Natl. Acad. Sci. U.S.A. 2004, 101, 14011–14016.
Chen, X. H.; Turecček, F. The arginine anomaly: Arginine radicals are poor hydrogen atom donors in electron transfer induced dissociations. J. Am. Chem. Soc. 2006, 128, 12520–12530.
Syrstad, E. A.; Turecček, F. Hydrogen atom adducts to the amide bond: Generation and energetics of the amino(hydroxy)methyl radical in the gas phase. J. Phys. Chem. A 2001, 105, 11144–11155.
Syrstad, E. A.; Stephens, D. D.; Turecček, F. Hydrogen atom adducts to the amide bond: Generation and energetics of amide radicals in the gas phase. J. Phys. Chem. A 2003, 107, 115–126.
Syrstad, E. A.; Turecček, F. Toward a general mechanism of electron capture dissociation. J. Am. Soc. Mass Spectrom. 2005, 16, 208–224.
Turecček, F.; Syrstad, E. A.; Seymour, J. L.; Chen, X. H.; Yao, C. X. Peptide cation-radicals: A computational study of the competition between peptide N-Cα, bond cleavage and loss of the side chain in the [GlyPhe-NH2+ 2H]+· cation-radical. J. Mass Spectrom. 2003, 38, 1093–1104.
Turecček, F. N-Cα bond dissociation energies and kinetics in amide and peptide radicals: Is the dissociation a nonergodic process? J. Am. Chem. Soc. 2003, 125, 5954–5963.
Turecček, F.; Syrstad, E. A. Mechanism and energetics of intramolecular hydrogen transfer in amide and peptide radicals and cation radicals. J. Am. Chem. Soc. 2003, 125, 3353–3369.
Kruger, N. A.; Zubarev, R. A.; Carpenter, B. K.; Kelleher, N. L.; Horn, D. M.; McLafferty, F. W. Electron capture versus energetic dissociation of protein ions. Int. J. Mass Spectrom. 1999, 183, 1–5.
Sobczyk, M.; Simons, J. Distance dependence of through-bond electron transfer rates in electron-capture and electron-transfer dissociation. Int. J. Mass Spectrom. 2006, 253, 274–280.
Sobczyk, M.; Simons, J. The role of excited Rydberg states in electron transfer dissociation. J. Phys. Chem. B 2006, 110, 7519–7527.
Anusiewicz, I.; Berdys-Kochanska, J.; Skurski, P.; Simons, J. Simulating electron transfer attachment to a positively charged model peptide. J. Phys. Chem. A 2006, 110, 1261–1266.
Sawicka, A.; Skurski, P.; Hudgins, R. R.; Simons, J. Model calculations relevant to disulfide bond cleavage via electron capture influenced by positively charged groups. J. Phys. Chem. B 2003, 107, 13505–13511.
Robinson, E. W.; Leib, R. D.; Williams, E. R. The role of conformation on electron capture dissociation of ubiquitin. J. Am. Soc. Mass Spectrom. 2006, 17, 1469–1479.
Chakraborty, T.; Holm, A. I. S.; Hvelplund, P.; Nielsen, S. B.; Poully, J.-C.; Worm, E. S.; Williams, E. R. On the survival of peptide cations after electron capture: Role of internal hydrogen bonding and microsolvation. J. Am. Soc. Mass Spectrom. 2006, 17, 1675–1680.
Liu, H.; Håkansson, K. Electron capture dissociation of tyrosine O-sulfated peptides complexed with divalent metal cations. Anal. Chem. 2006, 78, 7570–7576.
Liu, H.; Håkansson, K. Divalent metal ion-peptide interactions probed by electron capture dissociation of trications. J. Am. Soc. Mass Spectrom. 2006, 17, 1731–1741.
Leymarie, N.; Costello, C. E.; O’Connor, P. B. Electron capture dissociation initiates a free radical reaction cascade. J. Am. Chem. Soc. 2003, 125, 8949–8958.
Lin, C.; O’Connor, P. B.; Cournoyer, J. J. Use of a double resonance electron capture dissociation experiment to probe fragment intermediate lifetimes. J. Am. Soc. Mass Spectrom. 2006, 17, 1605–1615.
O’Connor, P. B.; Lin, C.; Cournoyer, J. J.; Pittman, J. L.; Belyayev, M.; Budnik, B. A. Long-lived electron capture dissociation product ions experience radical migration via hydrogen abstraction. J. Am. Soc. Mass Spectrom. 2006, 17, 576–585.
Iavarone, A. T.; Paech, K.; Williams, E. R. Effects of charge state and cationizing agent on the electron capture dissociation of a peptide. Anal. Chem. 2004, 76, 2231–2238.
Griffiths, I. W.; Mukhtar, E. S.; March, R. E.; Harris, F. M.; Beynon, J. H. Comparison of photo-excitation of ions and collisional excitation using gases. Int. J. Mass Spectrom. Ion Phys. 1981, 39, 125–132.
Baer, T.; Dutuit, O.; Mestdagh, H.; Rolando, C. Dissociation dynamics of normal-butylbenzene ions—the competitive production of m/z 91-fragment and 92-fragment ions. J. Phys. Chem. 1988, 92, 5674–5679.
Chen, J. H.; Hays, J. D.; Dunbar, R. C. Competitive 2-channel photodissociation of normal-butylbenzene ions in the Fourier-transform ion-cyclotron resonance mass-spectrometer. J. Phys. Chem. 1984, 88, 4759–4764.
Kenttämaa, H. I.; Cooks, R. G. Internal energy-distributions acquired through collisional activation at low and high-energies. Int. J. Mass Spectrom. Ion Processes 1985, 64, 79–83.
Dekrey, M. J.; Kenttämaa, H. I.; Wysocki, V. H.; Cooks, R. G. Energy deposition in Fe(CO) +·5 Upon collision with a metal-surface. Org. Mass Spectrom. 1986, 21, 193–195.
Beranova, S.; Wesdemiotis, C. Internal energy-distributions of tungsten hexacarbonyl ions after neutralization-reionization. J. Am. Soc. Mass Spectrom. 1994, 5, 1093–1101.
Nguyen, V. Q.; Turecček, F. Protonation sites in gaseous pyrrole and imidazole: A neutralization-reionization and ab initio study. J. Mass. Spectrom. 1996, 31, 1173–1184.
Schnier, P. D.; Jurchen, J. C.; Williams, E. R. The effective temperature of peptide ions dissociated by sustained off-resonance irradiation collisional activation in Fourier transform mass spectrometry. J. Phys. Chem. B. 1999, 103, 737–745.
Price, W. D.; Schnier, P. D.; Jockusch, R. A.; Strittmatter, E. F.; Williams, E. R. Unimolecular reaction kinetics in the high-pressure limit without collisions. J. Am. Chem. Soc. 1996, 118, 10640–10644.
Wong, R. L.; Paech, K.; Williams, E. R. Blackbody infrared radiative dissociation at low temperature: Hydration of X2+(H2O) n , for X = Mg, Ca. Int. J. Mass Spectrom. 2004, 232, 59–66.
Bush, M. F.; Saykally, R. J.; Williams, E. R. Formation of hydrated triply charged metal ions from aqueous solutions using nanodrop mass spectrometry. Int. J. Mass Spectrom. 2006, 253, 256–262.
Siu, C. K.; Liu, Z. F. Ab initio studies on the mechanism of the size-dependent hydrogen-loss reaction in Mg+(H2O)n. Chem. Eur. J. 2002, 8, 3177–3186.
Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.; Robb, M. A.; Cheeseman, J. R.; Montgomery, J. J. A.; Vreven, T.; Kudin, K. N.; Burant, J. C.; Millam, J. M.; Iyengar, S. S.; Tomasi, J.; Barone, V.; Mennucci, B.; Cossi, M.; Scalmani, G.; Rega, N.; Petersson, G. A.; Nakatsuji, H.; Hada, M.; Ehara, M.; Toyota, K.; Fukuda, R.; Hasegawa, J.; Ishida, M.; Nakajima, T.; Honda, Y.; Kitao, O.; Nakai, H.; Klene, M.; Li, X.; Knox, J. E.; Hratchian, H. P.; Cross, J. B.; Bakken, V.; Adamo, C.; Jaramillo, J.; Gomperts, R.; Stratmann, R. E.; Yazyev, O.; Austin, A. J.; Cammi, R.; Pomelli, C.; Ochterski, J. W.; Ayala, P. Y.; Morokuma, K.; Voth, G. A.; Salvador, P.; Dannenberg, J. J.; Zakrzewski, V. G.; Dapprich, S.; Daniels, A. D.; Strain, M. C.; Farkas, O.; Malick, D. K.; Rabuck, A. D.; Raghavachari, K.; Foresman, J. B.; Ortiz, J. V.; Cui, Q.; Baboul, A. G.; Clifford, S.; Cioslowski, J.; Stefanov, B. B.; Liu, G.; Liashenko, A.; Piskorz, P.; Komaromi, I.; Martin, R. L.; Fox, D. J.; Keith, T.; Al-Laham, M. A.; Peng, C. Y.; Nanayakkara, A.; Challacombe, M.; Gill, P. M. W.; Johnson, B.; Chen, W.; Wong, M. W.; Gonzalez, C.; Pople, J. A. Gaussian 03, Revision C. 02; Gaussian, Inc.: Wallingford, CT, 2004.
Cody, R. B.; Freiser, B. S. Electron-impact excitation of ions from organics—alternative to collision-induced dissociation. Anal. Chem. 1979, 51, 547–551.
Polfer, N. C.; Haselmann, K. F.; Zubarev, R. A.; Langridge-Smith, P. R. R. Electron capture dissociation of polypeptides using a 3 Tesla Fourier transform ion cyclotron resonance mass spectrometer. Rapid Commun. Mass Spectrom. 2002, 16, 936–943.
Kjeldsen, F.; Haselmann, K. F.; Budnik, B. A.; Jensen, F.; Zubarev, R. A. Dissociative capture of hot (3–13 eV) electrons by polypeptide polycations: An efficient process accompanied by secondary fragmentation. Chem. Phys. Lett. 2002, 356, 201–206.
Harms, A. C.; Khanna, S. N.; Chen, A. B.; Castleman, A. W. Dehydrogenation reactions in Mg+(H2O) n clusters. J. Chem. Phys. 1994, 100, 3540–3544.
Sanekata, M.; Misaizu, F.; Fuke, K.; Iwata, S.; Hashimoto, K. Reactions of singly charged alkaline-earth metal-ions with water clusters—characteristic size distribution of product ions. J. Am. Chem. Soc. 1995, 117, 747–754.
Berg, C.; Beyer, M.; Achatz, U.; Joos, S.; Niedner-Schatteburg, G.; Bondybey, V. E. Stability and reactivity of hydrated magnesium cations. Chem. Phys. 1998, 239, 379–392.
Dzidic, I.; Kebarle, P. Hydration of alkali ions in gas phase — enthalpies and entropies of reactions Mg+(H2O) n−1 + H2O = Mg+(H2O) n . J. Phys. Chem. 1970, 74, 1466–1474.
Shi, Z.; Ford, J. V.; Wei, S.; Castleman, A. W. Water clusters—contributions of binding-energy and entropy to stability. J. Chem. Phys. 1993, 99, 8009–8015.
Dalleska, N. F.; Tjelta, B. L.; Armentrout, P. B. Sequential bond-energies of water to Na+ [3s(0)], Mg+ [3s(1)] and Al+ [3s(2)]. J. Phys. Chem. 1994, 98, 4191–4195.
McLafferty, F. W.; Wachs, T.; Lifshitz, C.; Innorta, G.; Irving, P. Substituent effects in unimolecular ion decompositions. 15: Mechanistic interpretations and quasi-equilibrium theory. J. Am. Chem. Soc. 1970, 92, 6867–6880.
Leib, R. D.; Donald, W. A.; Bush, M. F.; O’Brien, J. T.; Williams, E. R. Internal energy deposition in electron capture dissociation measured using hydrated divalent metal ions as nanocalorimeters. J. Am. Chem. Soc. 2007, 129, 4894–4895.
Kebarle, P.; Searles, S. K.; Zolla, A.; Scarborough, J.; Arshadi, M. The solvation of the hydrogen ion by water molecules in the gas phase: Heats and entropies of solvation of individual reactions: H+(H2O) n-1+ H2O -> H+(H2O) n . J. Mass Spectrom. 1997, 32, 915–921.
Marsh, K. N. Recommended reference materials for the realization of physiochemical properties; Blackwell: Oxford, 1987; p 275.
Feistel, R.; Wagner, W. A new equation of state for H2O ice Ih. J. Phys. Chem. Ref. Data 2006, 35, 1021–1047.
Klots, C. E. Evaporative cooling. J. Chem. Phys. 1985, 83, 5854–5860.
Watanabe, H.; Iwata, S. Molecular-orbital studies of the structures and reactions of a singly charged calcium ion with water clusters, Ca+(H2O) n . J. Phys. Chem. A 1997, 101, 487–496.
Inokuchi, Y.; Ohshimo, K.; Misaizu, F.; Nishi, N. Infrared photodissociation spectroscopy of [Mg · (H2O)1−4]+ and [Mg · (H2O)1−4 · Ar1]+. J. Phys. Chem. A. 2004, 108, 5034–5040.
Reinhard, B. M.; Niedner-Schatteburg, G. Ionization energies and spatial volumes of the singly occupied molecular orbital in hydrated magnesium clusters Mg(H2O) 2+ n . J. Chem. Phys. 2003, 118, 3571–3582.
Coe, J. V. Fundamental properties of bulk water from cluster ion data. Int. Rev. Phys. Chem. 2001, 20, 33–58.
Märk, T. D. Free electron attachment to van der Waals clusters. Int. J. Mass Spectrom. Ion Processes 1991, 107, 143–163.
Fedor, J.; Cicman, P.; Coupier, B.; Feil, S.; Winkler, M.; Gluch, K.; Husarik, J.; Jaksch, D.; Farizon, B.; Mason, N. J.; Scheier, P.; Märk, T. D. Fragmentation of transient water anions following low-energy electron capture by H2O/D2O. J. Phys. B At. Mol. Phys. 2006, 39, 3935–3944.
Belic, D. S.; Landau, M.; Hall, R. I. Energy and angular-dependence of H−(D−) ions produced by dissociative electron-attachment to H2O (D2O). J. Phys. B At. Mol. Phys. 1981, 14, 175–190.
Baer, T.; Hase, W. L. Unimolecular reaction dynamics: Theory and experiments; Oxford University Press: New York, 1996; pp. 324–368.
Misaizu, F.; Sanekata, M.; Fuke, K.; Iwata, S. Photodissociation study on Mg+(H2O) n , n. = 1−5: Electronic structure and photoinduced intracluster reaction. J. Chem. Phys. 1994, 100, 1161–1170.
Misaizu, F.; Sanekata, M.; Tsukamoto, K.; Fuke, K.; Iwata, S. Photodissociation of size-selected Mg+(H2O) n ions for n = 1 and 2. J. Phys. Chem. 1992, 96, 8259–8264.
Anders, L. R.; Beauchamp, J. L.; Dunbar, R. C.; Baldeschwieler, J. D. Ion-cyclotron double resonance. J. Chem. Phys. 1966, 45, 1062–1063.
Jurchen, J. C.; Garcia, D. E.; Williams, E. R. Gas-phase dissociation pathways of multiply charged peptide clusters. J. Am. Soc. Mass Spectrom. 2003, 14, 1373–1386.
Dye, J. L. Electrons as anions. Science 2003, 301, 607–608.
Dye, J. L. Electrides—ionic salts with electrons as the anions. Science 1990, 247, 663–668.
Matsuishi, S.; Toda, Y.; Miyakawa, M.; Hayashi, K.; Kamiya, T.; Hirano, M.; Tanaka, I.; Hosono, H. High-density electron anions in a nanoporous single crystal: [Ca24Al28O64]4+4e−. Science 2003, 301, 626–629.
Author information
Authors and Affiliations
Corresponding author
Additional information
Published online April 15, 2007
Rights and permissions
About this article
Cite this article
Leib, R.D., Donald, W.A., Bush, M.F. et al. Nonergodicity in electron capture dissociation investigated using hydrated ion nanocalorimetry. J Am Soc Mass Spectrom 18, 1217–1231 (2007). https://doi.org/10.1016/j.jasms.2007.03.033
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1016/j.jasms.2007.03.033