Abstract
The clustering of a medium-sized, involatile, neutral molecule, octyl β-D-glucopyranoside (OG), with Na+, Ca2+, and Yb3+ (Mz+) ions in electrospray (ESI) was investigated using laser spray (LSI). Extensive distributions of [(Mz+)i (OG)a]n+-clusters, extending beyond 50 kDa, were observed. The distributions were highly stable and reproducible and changed only marginally when concentrations of electrolyte or neutral compound were varied by orders of magnitude. Compared with ESI, laser spray yielded superior intensities, particularly of the larger clusters. The cluster distributions demonstrated a range of remarkable features. In particular, the Yb3+/OG cluster distribution was unusual. For example, no clusters with 35–52 or with 110–116 OG molecules were observed. The distribution pattern revealed that the clusters were formed as a result of cluster dissociations, such as [(Yb3+)3(OG) ∼110W]9+→[(Yb3+)2(OG)∼90W]6++[(Yb3+)1(OG) ∼20W]3+, where W represents the water content at the time of dissociation. Based on this study, a cluster division model for electrospray of aqueous solutions of strongly solvated ions is proposed: the Rayleigh droplet disintegration process, which is well-established for the initial stages of electrospray, maintains its general character as it proceeds through a final regime of multiply charged cluster dissociations to the singly and multiply charged ions in mass spectrometry. In the dissociation of multiply charged clusters, the size of each daughter cluster is roughly proportional to the square of the cluster charge. Observed cluster distributions are consistent with a mixture of symmetric and asymmetric cluster dissociations.
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Whitehouse, C. M.; Dreyer, R. N.; Yamashita, M.; Fenn, J. B. Electrospray interface for liquid chromatographs and mass spectrometers. Anal. Chem. 1985, 57, 675–679.
Yamashita, M.; Fenn, J. B. Negative-ion production with the electrospray ion-source. J. Phys. Chem. 1984, 88, 4671–4675.
Bruins, A. P.; Covey, T. R.; Henion, J. D. Ion spray interface for combined liquid chromatography/atmospheric pressure ionization mass spectrometry. Anal. Chem. 1987, 59, 2642–2646.
Rayleigh, L. On the equilibrium of liquid conducting masses charged with electricity. Phil. Mag. 1882, 14, 184–186.
Smith, J. N.; Flagan, R. C.; Beauchamp, J. L. Droplet evaporation and discharge dynamics in electrospray ionization. J. Phys. Chem. A 2002, 106, 9957–9967.
Grimm, R. L.; Beauchamp, J. L. Evaporation and discharge dynamics of highly charged droplets of heptane, octane, and p-xylene generated by electrospray ionization. Anal. Chem. 2002, 74, 6291–6297.
Gomez, A.; Tang, K. Q. Charge and fission of droplets in electrostatic sprays. Phys. Fluids 1994, 6, 404–414.
Kebarle, P.; Tang, L. From ions in solution to ions in the gas-phase—the mechanism of electrospray mass-spectrometry. Anal. Chem. 1993, 65, A972-A986.
Kebarle, P. A brief overview of the present status of the mechanisms involved in electrospray mass spectrometry. J. Mass Spectrom. 2000, 35, 804–817.
Cech, N. B.; Enke, C. G. Practical implications of some recent studies in electrospray ionization fundamentals. Mass Spectrom. Rev. 2001, 20, 362–387.
Enke, C. G. A predictive model for matrix and analyte effects in electrospray ionization of singly-charged ionic analytes. Anal. Chem. 1997, 69, 4885–4893.
Iribarne, J. V.; Thomson, B. A. Evaporation of small ions from charged droplets. J. Chem. Phys. 1976, 64, 2287–2294.
Thomson, B. A.; Iribarne, J. V. Field-induced ion evaporation from liquid surfaces at atmospheric-pressure. J. Chem. Phys. 1979, 71, 4451–4463.
Thomson, B. A.; Iribarne, J. V.; Dziedzic, P. J. Liquid ion evaporation mass-spectrometry mass-spectrometry for the detection of polar and labile molecules. Anal. Chem. 1982, 54, 2219–2224.
Dole, M.; Mack, L. L.; Hines, R. L.; Mobley, R. C.; Ferguson, L. P.; Alice, M. B. Molecular beams of macro-ions. J. Chem. Phys. 1968, 49, 2240–2249.
Kebarle, P.; Peschke, M. On the mechanisms by which the charged droplets produced by electrospray lead to gas phase ions. Anal. Chim. Acta 2000, 406, 11–35.
Gamero-Castano, M.; de la Mora, J. F. Kinetics of small ion evaporation from the charge and mass distribution of multiply charged clusters in electrosprays. J. Mass Spectrom. 2000, 35, 790–803.
de la Mora, J. F. Electrospray ionization of large multiply charged species proceeds via Dole’s charged residue mechanism. Anal. Chim. Acta 2000, 406, 93–104.
Gamero-Castano, M.; de la Mora, J. F. Modulations in the abundance of salt clusters in electrosprays. Anal. Chem. 2000, 72, 1426–1429.
Gamero-Castano, M.; de la Mora, J. F. Mechanisms of electrospray ionization of singly and multiply charged salt clusters. Anal. Chim. Acta 2000, 406, 67–91.
Gamero-Castano, M.; de la Mora, J. F. Direct measurement of ion evaporation kinetics from electrified liquid surfaces. J. Chem. Phys. 2000, 113, 815–832.
Hiraoka, K. Laser spray: Electric field-assisted matrix-assisted laser desorption/ionization. J. Mass Spectrom. 2004, 39, 341–350.
Takamizawa, A.; Fujimaki, S.; Sunner, J.; Hiraoka, K. Denaturation of lysozyme and myoglobin in laser spray. J. Am. Soc. Mass Spectrom. 2005, 16, 860–868.
Fenn, J. B.; Mann, M.; Meng, C. K.; Wong, S. F.; Whitehouse, C. M. Electrospray ionization for mass spectrometry of large biomolecules. Science 1989, 246, 64–71.
Wong, S. F.; Meng, C. K.; Fenn, J. B. Multiple charging in electrospray ionization of poly(ethylene glycols). J. Phys. Chem. 1988, 92, 546–550.
Fenn, J. B.; Mann, M.; Meng, C. K.; Wong, S. F.; Whitehouse, C. M. Electrospray ionization—principles and practice. Mass Spectrom. Rev. 1990, 9, 37–70.
Meng, C. K.; Fenn, J. B. Formation of charged clusters during electrospray ionization of organic solute species. Org. Mass Spectrom. 1991, 26, 542–549.
Zook, D. R.; Bruins, A. P. On cluster ions, ion transmission, and linear dynamic range limitations in electrospray (ion spray) mass spectrometry. Int. J. Mass Spectrom. Ion Processes 1997, 162, 129–147.
Zhou, S. L.; Hamburger, M. Formation of sodium cluster ions in electrospray mass spectrometry. Rapid Commun. Mass Spectrom. 1996, 10, 797–800.
Hop, C. E. C. A. Generation of high molecular weight cluster ions by electrospray ionization: Implications for mass calibration. J. Mass Spectrom. 1996, 31, 1314–1316.
Wang, G. D.; Cole, R. B. Solvation energy and gas-phase stability influences on alkali metal cluster ion formation in electrospray ionization mass spectrometry. Anal. Chem. 1998, 70, 873–881.
Charles, L.; Pepin, D.; Gonnet, F.; Tabet, F. C. Effects of liquid phase composition on salt cluster formation in positive ion mode electrospray mass spectrometry: Implications for clustering mechanism in electrospray. J. Am. Soc. Mass Spectrom. 2001, 12, 1077–1084.
Hao, C. Y.; March, R. E. Electrospray ionization tandem mass spectrometric study of salt cluster ions. Part 2. Salts of polyatomic acid groups and of multivalent metals. J. Mass Spectrom. 2001, 36, 509–521.
Hao, C. Y.; March, R. E.; Croley, T. R.; Smith, J. C.; Rafferty, S. P. Electrospray ionization tandem mass spectrometric study of salt cluster ions: Part 1. Investigations of alkali metal chloride and sodium salt cluster ions. J. Mass Spectrom. 2001, 36, 79–96.
Siuzdak, G.; Bothner, B. Gas-phase micelles. Angew. Chem. Int. Ed. 1995, 34, 2053–2055.
Nohara, D.; Ohkoshi, T.; Sakai, T. The possibility of the direct measurement of micelle weight by electrospray ionization mass spectrometry. Rapid Commun. Mass Spectrom. 1998, 12, 1933–1935.
Nohara, D.; Bitoh, M. Observation of micelle solution of decyltrimethylammonium bromide by electrospray ionization mass spectrometry. J. Mass Spectrom. 2000, 35, 1434–1437.
Cacace, F.; de Petris, G.; Giglio, E.; Punzo, F.; Troiani, A. Bile salt aggregates in the gas phase: An electrospray ionization mass spectrometric study. Chem. A Eur. J. 2002, 8, 1925–1933.
Rodriguez, M. A.; Yost, R. A. Interpretation of electrospray/ion trap mass spectra of bile acids and other surfactants. Rapid Commun. Mass Spectrom. 2000, 14, 1398–1403.
Nohara, D.; Kajiura, T.; Takeda, K. Determination of micelle mass by electrospray ionization mass spectrometry. J. Mass Spectrom. 2005, 40, 489–493.
Schalley, C. A. Supramolecular chemistry goes gas phase: The mass spectrometric examination of noncovalent interactions in host-guest chemistry and molecular recognition. Int. J. Mass Spectrom. 2000, 194, 11–39.
Dreisewerd, K. The desorption process in MALDI. Chem. Rev. 2003, 103, 395–425.
Karas, M.; Kruger, R. Ion formation in MALDI: The cluster ionization mechanism. Chem. Rev. 2003, 103, 427–439.
Sunner, J.; Morales, A.; Kebarle, P. Kinetic modeling of fast atom bombardment spectra of glycerol. Anal. Chem. 1988, 60, 98–104.
Sunner, J.; Ikonomou, M. G.; Kebarle, P. SIMS spectra of alcohols and the phase explosion model of desorption ionization. Int. J. Mass Spectrom. Ion Processes 1988, 82, 221–237.
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Published online January 19, 2006
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Sunner, J., Beech, I.B. & Hiraoka, K. On the distributions of ion/neutral molecule clusters in electrospray and laser spray—A cluster division model for the electrospray process. The official journal of The American Society for Mass Spectrometry 17, 151–162 (2006). https://doi.org/10.1016/j.jasms.2005.10.006
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DOI: https://doi.org/10.1016/j.jasms.2005.10.006