Abstract
In-trap fragmentation of ions in a hybrid linear ion trap triple quadrupole mass spectrometer occurs at pressures about 5e-5 torr. At these low pressures, efficient fragmentation of heavy ions (such as the singly charged homogenously substituted triazatriphosphorine of mass 2721.89 Da) can take a long time because of the relatively low collision frequency with the background gas and the high internal energy content required to produce fragmentation. Increasing the amplitude used for dipolar excitation leads to loss of the ion upon the quadrupole rods. In the work presented here, the addition of a dc octopolar field to a linear ion trap is described. The dc octopolar field was created by the addition of four auxiliary electrodes situated between the quadrupole rods at a distance of 10 mm from the axis. The inclusion of the dc octopolar field was shown to cause the ions’ frequency of motion to shift out of phase with the excitation signal at high radial amplitudes. This resulted in beat-like trajectories with periods of excitation and de-excitation as the ions’ frequency of motion shifted in and out of phase with the excitation signal. This led to a reduction in the loss of ions on the quadrupole rods during the excitation process. The result is an increased fragmentation efficiency relative to the fragmentation efficiency obtained when using an LIT constructed of round rods only. The inclusion of the dc octopolar field allowed the ion to be fragmented more efficiently in a relatively short excitation period.
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Collings, B. A.; Stott, W. R.; Londry, F. A. Resonant Excitation in a Low Pressure Linear Ion Trap. J. Am. Soc. Mass Spectrom. 2003, 14, 622–634.
Michaud, A. L.; Frank, A. J.; Ding, C.; Douglas, D. J. Ion Excitation in a Linear Quadrupole Ion Trap with an Added Octopole Field. J. Am. Soc. Mass Spectrom. 2005, 16, 835–849.
Hager, J. W. A New Linear Ion Trap Mass Spectrometer. Rapid Commun. Mass Spectrom. 2002, 16, 512–526.
Douglas, D. J.; Glebova, T. A.; Konenkov, N. V.; Sudakov, M. Y. Spatial Harmonics of the Field in a Quadrupole Mass Filer with Circular Electrodes. Tech. Phys. 1999, 44, 1215–1219.
Sudakov, M.; Douglas, D. J. Linear Quadrupoles with Added Octopole Fields. Rapid Commun. Mass Spectrom. 2003, 17, 2290–2294.
Gerlich, D. Inhomogeneous rf Fields: A Versatile Tool for the Study of Processes with Slow Ions. In Advances in Chemical Physics, Vol. 82. Ng, C-Y; Baer, M., eds. John Wiley and Sons, Inc.: New York, 1992, pp 1–176.
Franzen, J.; Gabling, R.-H.; Heinen, G.; Weiss, G. Method for Mass Spectroscopic Examination of a Gas Mixture and Mass Spectrometer Intended for Carrying Out This Method. U.S. Patent 5, 028, 777, 1991.
Wang, Y.; Franzen, J.; Wanczek, K. P. The Non-linear Resonance Ion Trap. Part 2. A General Theoretical Analysis. Int. J. Mass Spectrom. Ion Processes 1993, 124, 125–144.
Franzen, J. Simulation Study of an Ion Cage with Superimposed Multipole Fields. Int. J. Mass Spectrom. Ion Processes 1991, 106, 63–78.
Franzen, J.; Wang, Y. Quadrupole Ion Trap with Switchable Multipole Fractions. U.S. Patent 5, 468, 958, 1995.
Franzen, J.; Wang, Y. Quadrupole Ion Trap with Switchable Multipole Fractions. U.S. Patent Re. 36, 906, 1995.
Londry, F.; Collings, B. A.; Stott, W. R. Fragmentation of Ions by Resonant Excitation in a Higher Order Multipole Field, Low Pressure Ion Trap. U.S. Patent Application 0189171 A1, 2003.
Loboda, A.; Krutchinsky, A.; Loboda, O.; McNabb, J.; Spicer, V.; Ens, W.; Standing, K. Novel LINAC II Electrode Geometry for Creating an Axial Field in a Multipole Ion Guide. Eur. J. Mass Spectrom 2000, 6, 531–536.
Londry, F. A.; Hager, J. W. Mass Selective Axial Ion Ejection from a Linear Quadrupole Ion Trap. J. Am. Soc. Mass Spectrom. 2003, 14, 1130–1147.
Flanagan, J. M. Mass Spectrometry Calibration Using Homogeneously Substituted Fluorinated Triazatriphosphorines. U.S. Patent 5,872,357, 1999.
Covey, T.; Douglas, D. J. Collision Cross Sections for Protein Ions. J. Am. Soc. Mass Spectrom. 1993, 4, 616–623.
Dahl, D. A. Simion 3-D Version 7.0, Publication INEEL-95/0403; Idaho National Engineering and Environmental Laboratory: Idaho Falls, Idaho, 2000.
Dehmelt, H. G. Radiofrequency Spectroscopy of Stored Ions: Storage. Adv. Atom. Mol. Phys. 1967, 3, 53–72.
Dawson, P. H. Quadrupole Mass Spectrometry and Its Applications; AIP Press: Woodbury, NY, 1995; pp 13–14.
French, A. P. Vibrations and Waves; W. W Norton and Company, Inc.: New York, NY, 1971; pp 189–196.
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Published online June 24, 2005
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Collings, B.A. Increased Fragmentation Efficiency of Ions in a Low Pressure Linear Ion Trap with an Added dc Octopole Field. J Am Soc Mass Spectrom 16, 1342–1352 (2005). https://doi.org/10.1016/j.jasms.2005.03.049
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DOI: https://doi.org/10.1016/j.jasms.2005.03.049