Ion injection and activation in the quadrupole ion trap mass spectrometer
The goal of this thesis is to provide understanding concerning ion injection and ion activation in the quadrupole ion trap mass spectrometer. Ion trap mass spectrometry has a variety of applications concerned with the analysis large proteins and biomolecules. However, such experiments have been plagued by limited mass measurement accuracy as ions are not ejected in a predictable manner. Examination of the solution to the [open quotes]forced[close quotes], [open quotes]damped[close quotes] Mathieu equation and an understanding of the behavior of ions under the influence of space charge allow a qualitative prediction of ion behavior and such predictions have a direct outcome on the ability to perform experiments with high mass accuracy. For ions which are sufficiently separated in m/z ratio, mass measurement errors occur as a result of off-resonance energy absorption by the ion which leads to early ejection of the ion, while errors for ions which are in close proximity, [le]1 da/charge separation, result from combination of off-resonance absorption and the presence of space charge conditions which lead to irregular peak separations. However, the analysis of large biomolecules requires the efficient collection of ions injected into the trap and energy deposition processes which were not typically available. The use of a combination of the helium buffer gas with a small amount of a heavier mass target effects both the trapping efficiency and the deposition of much higher internal energies in the selected ion without deleterious effects of ion loss due to scattering. For ions with m/z ratios greater than 8000 da/charge the use of buffer mixtures is shown to increase the trapping efficiency by as much as 200%. In addition, collision-induced dissociation experiments performed on thermometer-type species, such as pyrene, confirm that up to 23 volts of internal energy may be deposited in a single MS/MS experiment and should be applicable for the dissociation of biomolecules.
- Research Organization:
- Purdue Univ., Lafayette, IN (United States)
- OSTI ID:
- 6960002
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
IONS
MATHIEU EQUATION
MASS SPECTROMETERS
ION BEAM INJECTION
TRAPPING
QUADRUPOLES
BEAM INJECTION
CHARGED PARTICLES
DIFFERENTIAL EQUATIONS
EQUATIONS
MEASURING INSTRUMENTS
MULTIPOLES
SPECTROMETERS
665100* - Nuclear Techniques in Condensed Matter Physics - (1992-)
400102 - Chemical & Spectral Procedures