Correlations of chemical mass shifts of para-substituted acetophenones and benzophenones with brown’s σ p + constants

  • Yanan Peng
  • Wolfgang R. Plass
  • R. Graham CooksEmail author
Focus: Quadrupole Ion Traps


Relationships between chemical mass shifts and physiochemical properties of ions are sought by examining substituted acetophenones, benzophenones, and pyridines in a modified ion trap mass spectrometer. Systematic changes in chemical mass shift occur with changes in substituent in the acetophenones and the benzophenones. Brown’s σ+ constant, which is a measure of electronic effects of substituents in reactions that involve positive charge development, is shown to correlate linearly with chemical mass shifts in para-substituted acetophenones and benzophenones. Brown’s σ+ constant also correlates with the ease of dissociation of the ions via a correlation with ionization energy. It is suggested that ease of dissociation is the underlying factor in determining chemical mass shifts. The experimental results also suggest that dissociative collisions between ions and buffer gas make a much greater contribution to chemical mass shifts than do elastic collisions.


Acetophenones Benzophenone Mass Shift Substituent Effect Chemical Mass Shift 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


  1. 1.
    Paul, W.; Steinwedel, H. A New Mass Spectrometer without a Magnetic Field. Z. Naturforsch. 1953, 8a, 448.Google Scholar
  2. 2.
    Stafford, G. C.; Kelley, P. E.; Syka, J. E. P.; Reynolds, W. E.; Todd, J. F. J. Recent Improvements in and Analytical Applications of Advanced Ion Trap Technology. Int. J. Mass Spectrom. Ion Processes 1984, 60, 85–98.CrossRefGoogle Scholar
  3. 3.
    Schwartz, J. C.; Hememway, T. A. Practical Aspects of Obtaining Higher Resolution on an API Quadrupole Ion Trap and the Implications for Accurate Mass Measurements. Proceedings of the 48th ASMS Conference on Mass Spectrometry and Allied Topics; Long Beach, CA, June 11–15, 2000; MPB 070.Google Scholar
  4. 4.
    Langmuir, D. B.; Langmuir, R. V.; Shelton, H.; Wuerker, R. F. Containment Device; United States Patent No. 3,065,640 1962.Google Scholar
  5. 5.
    Wells, J. M.; Badman, E. R.; Cooks, R. G. A Quadrupole Ion Trap of Cylindrical Geometry Operated in the Mass Selective Instability Mode. Anal. Chem. 1998, 70, 438–444.CrossRefGoogle Scholar
  6. 6.
    Badman, E. R.; Wells, J. M.; Bui, H. A.; Cooks, R. G. Fourier Transform Detection in a Cylindrical Quadrupole Ion Trap. Anal. Chem. 1998, 70, 3545–3547.CrossRefGoogle Scholar
  7. 7.
    Badman, E. R.; Johnson, R. C.; Plass, W. R.; Cooks, R. G. A Miniature Cylindrical Quadrupole Ion Trap: Simulation and Experiment. Anal. Chem. 1998, 70, 4896–4901.CrossRefGoogle Scholar
  8. 8.
    Cooks, R. G.; Rockwood, A. L. The Thomson—A Suggested Unit for Mass Spectroscopists. Rapid Commun. Mass Spectrom. 1991, 5, 93.Google Scholar
  9. 9.
    Knight, R. D. The General Form of the Quadrupole Ion Trap Potential. Int. J. Mass Spectrom. Ion Physics 1983, 51, 127.CrossRefGoogle Scholar
  10. 10.
    Syka, J. E. P. In: Practical Aspects of Ion Trap Mass Spectrometry; March, R. E.; Todd, J. F. J., Eds.; CRC Press: Boca Raton, 1995; Vol. I, p 169.Google Scholar
  11. 11.
    Traldi, P.; Curcuruto, O.; Bortolini, O. Mass Displacement in Ion Trap Mass Spectrometry. Rapid Commun. Mass Spectrom. 1992, 6, 410.CrossRefGoogle Scholar
  12. 12.
    Traldi, P.; Favretto, D.; Catinella, S.; Bortolini, O. Mass Displacements in Quadrupolar Field Analyzers. Org. Mass Spectrom. 1993, 28, 745.CrossRefGoogle Scholar
  13. 13.
    Bortolini, O.; Spalluto, G.; Traldi, P. Relationship Between Mass Displacements and Dipole Moments of para-Substituted Pyridine Odd Electron Molecular Ions. Org. Mass Spectrom. 1994, 29, 269.CrossRefGoogle Scholar
  14. 14.
    Londry, F. A.; Morrison, R. J. S.; March, R. E. Mass Displacements Measured in a Quadrupole Ion Trap. Proceedings of the 43rd ASMS Conference on Mass Spectrometry and Allied Topics; Atlanta, GA, May 1995; p. 1124.Google Scholar
  15. 15.
    Cleven, C. D.; Cooks, R. G.; Garrett, A. W.; Nogar, N. S.; Hemberger, P. H. Radial Distributions and Ejection Times of Molecular Ions in an Ion Trap Mass Spectrometer: A Laser Tomography Study of Effects of Ion Density and Molecular Type. J. Phys. Chem. 1996, 100, 40–46.CrossRefGoogle Scholar
  16. 16.
    Gill, L. A.; Amy, J. W.; Vaughn, W. E.; Cooks, R. G. In Situ Optimization of the Electrode Geometry of the Quadrupole Ion Trap. Int. J. Mass Spectrom. 1999, 188, 87–93.CrossRefGoogle Scholar
  17. 17.
    Gill, L. A.; Wells, J. M.; Patterson, G. E.; Amy, J. W.; Cooks, R. G. Resolution of Isobaric and Isomeric Ions Using Chemical Shifts in an Ion Trap Mass Spectrometer. Anal. Chem. 1998, 70, 4448–4452.CrossRefGoogle Scholar
  18. 18.
    Yost, R. A.; Murphy, J. P., III. Origin of Mass Shifts in the Quadrupole Ion Trap: Dissociation of Fragile Ions Observed with a Hybrid Ion Trap/Mass Filter Instrument. Rapid Commun. Mass Spectrom. 2000, 14, 270–273.CrossRefGoogle Scholar
  19. 19.
    Wells, J. M.; Plass, W. R.; Patterson, G. E.; Ouyang, Z.; Badman, E. R.; Cooks, R. G. Chemical Mass Shifts in Ion Trap Mass Spectrometry: Experiments and Simulations. Anal. Chem. 1999, 71, 3405–3415.CrossRefGoogle Scholar
  20. 20.
    Plass, W. R.; Wells, J. M.; Cooks, R. G. Chemical Mass Shifts in the RF Quadrupole Ion Trap: The Effect of Nonlinear Fields and Elastic and Dissociative Collisions on Absolute Ejection Times, Peak Shapes and Mass Measurement Accuracy. Proceedings of the 48th ASMS Conference on Mass Spectrometry and Allied Topics; Long Beach, CA, June 11–15, 2000, MPB 064.Google Scholar
  21. 21.
    Plass, W. The Dependence of RF Ion Trap Mass Spectrometer Performance on Electrode Geometry and Collisional Processes. Ph.D. Thesis, Justus-Liebig Universität Giessen, Germany, 2001; pp 79–112.Google Scholar
  22. 22.
    Wells, J. M.; Plass, W. R.; Cooks, R. G. Control of Chemical Mass Shifts in the Quadrupole Ion Trap through Selection of Resonance Ejection Working Point and rf Scan Direction. Anal. Chem. 2000, 72, 2677–2683.CrossRefGoogle Scholar
  23. 23.
    Reiser, H.-P.; Julian, R. K.; Cooks, R. G. A Versatile Method of Simulation of the Operation of Ion Trap Mass Spectrometers. Int. J. Mass Spectrom. Ion Processes 1992, 121, 49.CrossRefGoogle Scholar
  24. 24.
    Bui, H. A.; Cooks, R. G. Windows Version of the Ion Trap Simulation Program ITSIM: A Powerful Heuristic and Predictive Tool In Ion Trap Mass Spectrometry. J. Mass Spectrom. 1998, 33, 297–304.CrossRefGoogle Scholar
  25. 25.
    Billen, J. H.; Young, L. M. Poisson/Superfish on PC Compatibles. Proceedings of the Particle Accelerator Conference; Washington, DC, May 17–20, 1993; pp 790–792.Google Scholar
  26. 26.
    Wells, J. M.; Plass, W. R.; Patterson, G. E.; Ouyang, Z.; Badman, E. R.; Cooks, R. G. Chemical Mass Shifts in Ion Trap Mass Spectrometry. Proceedings of the 47th ASMS Conference on Mass Spectrometry and Allied Topics; Dallas, TX, June 13–18, 1999, WOC1035.Google Scholar
  27. 27.
    Hammett, L. P. Physical Organic Chemistry. McGraw-Hill Book Co., Inc.: New York, 1940, pp 184–228.Google Scholar
  28. 28.
    Brown, H. C.; Okamoto, Y. Directive Effects in Aromatic Substitution. XXX. Electrophilic Substituent Constants. J. Am. Chem. Soc. 1958, 80, 4979–4987.CrossRefGoogle Scholar
  29. 29.
    Harrison, A. G.; Kebarle, P.; Lossing, F. P. Free Radicals by Mass Spectrometry. XXI. The Ionization Potentials of Some meta- and para-Substituted Benzyl Radicals. J. Am. Chem. Soc. 1961, 83, 777–780.CrossRefGoogle Scholar
  30. 30.
    Tait, J. M. S.; Shannon, T. W.; Harrison, A. G. The Structure of Substituted C7 Ions from Benzyl Derivatives at the Appearance-Potential Threshold. J. Am. Chem. Soc. 1962, 84, 4–8.CrossRefGoogle Scholar
  31. 31.
    Bursey, M. M.; McLafferty, F. W. Substituent Effects in Unimolecular Ion Decompositions. IV. Correlations of Intensities of Ions Retaining the Substituent. J. Am. Chem. Soc. 1966, 89, 1–6.CrossRefGoogle Scholar
  32. 32.
    Bortolini, O.; Yang, S. S.; Cooks, R. G. Electrophilic Bromination of Gaseous Aromatic Compounds: Mechanism and Linear Free Energy Effects on Reaction Rates. Org. Mass Spectrom. 1993, 28, 1313–1322.CrossRefGoogle Scholar
  33. 33.
    Drahos, D.; Vekey, K. Mass Kinetics: A Theoretical Model of Mass Spectra Incorporating Physical Processes, Reaction Kinetics and Mathematical Descriptions. J. Mass Spectrom. 2001, 36, 237–263.CrossRefGoogle Scholar
  34. 34.
    70eV Electron Impact Spectra from the 1992 NIST Mass Spectral Database. Version 4.0.Google Scholar
  35. 35.
    Lambert, J. B.; Shurvell, H. F.; Lightner, D. A.; Cooks, R. G. Organic Structral Spectroscopy; Prentice-Hall, Inc.: Upper Saddle River, NJ, 1998; pp 392–437.Google Scholar
  36. 36.
    Levsen, K. Fundamental Aspects of Organic Mass Spectrometry; Weinheim: New York, 1978; pp 152–208.Google Scholar

Copyright information

© American Society for Mass Spectrometry 2002

Authors and Affiliations

  • Yanan Peng
    • 1
  • Wolfgang R. Plass
    • 1
  • R. Graham Cooks
    • 1
    Email author
  1. 1.Department of ChemistryPurdue UniversityWest LafayetteUSA

Personalised recommendations