Recent developments in analytical ion trap mass spectrometry (original) (raw)
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Improvements to the analytical performance of ion trap mass spectrometry
2006
Desmond Allen Kaplan Improvements to the Analytical Performance of Ion Trap Mass Spectrometry (Under the direction of Professor Gary L. Glish) Mass spectrometry is a powerful analytical technique that is capable of a wide range of chemical and biological analyses. The quadrupole ion trap mass spectrometer (QITMS) is known for its ruggedness, sensitivity, and high efficiency for tandem mass spectrometry (MS/MS) experiments. Non-idealities in electrode geometry result in small contributions of higher order fields (HOFs) to the primary quadrupolar electric field of the ion trap. These HOFs have been useful in enhancing the resolution, MS/MS efficiency, and sensitivity in the QITMS. A portion of the work presented in this dissertation is intended to serve as a basis for improved ion trap performance through the judicious use of HOFs. Development of rf circuitry and characterization of a compensated cylindrical ion trap (CCIT) mass spectrometer, designed for studying the effects of HOFs,...
Advances in Mass Spectrometry, 1992
Enhanced trajectory control m the quadrupole ion trap, m the presence of hehum buffer gas, has brought about enormous ~mprovements m mass range (mass hmlts m excess of 70000Da have been achieved), mass resolution (full width at half-maximum, 1 130000 at m/z 3510), and multistage tandem mass spectrometry (MS) n where n ~< 13 The compatlbdlty of the ion trap with external ion sources, such as electrospray and atmospheric pressure discharges, has greatly extended the range of apphcatlon of the ion trap Brief descriptions of the diagrammatic representation of ion trajectory stablhty and ion trapping theory precede a review of axial modulation, mass-selective axial ~on ejection, ~on ~solat~on, colhs~onreduced dissociation, tandem mass spectrometry and dynamically programmed scans The progress made during the past 3 years in all aspects of 1on trap mass spectrometry is reviewed
A two-dimensional quadrupole ion trap mass spectrometer
Journal of the American Society for Mass Spectrometry, 2002
The use of a linear or two-dimensional (2-D) quadrupole ion trap as a high performance mass spectrometer is demonstrated. Mass analysis is performed by ejecting ions out a slot in one of the rods using the mass selective instability mode of operation. Resonance ejection and excitation are utilized to enhance mass analysis and to allow isolation and activation of ions for MS n capability. Improved trapping efficiency and increased ion capacity are observed relative to a three-dimensional (3-D) ion trap with similar mass range. Mass resolution comparable to 3-D traps is readily achieved, including high resolution at slower scan rates, although adequate mechanical tolerance of the trap structure is a requirement. Additional advantages of 2-D over 3-D ion traps are also discussed and demonstrated. (J Am Soc Mass Spectrom 2002, 13, 659 -669)
International Journal of Mass Spectrometry and Ion Processes, 1988
A novel ion-trapping technique has been developed to facilitate the detection of reaction products formed in the central quadrupole of a triple quadrupole mass spectrometer. Ions that are produced by ion/molecule reactions are trapped for a variable period of time in the central quadrupole and are then pulsed toward the detector by means of an extraction lens. Full MS/MS scans using the repetitive trap and pulse technique have been achieved with no changes to the instrument hardware and only minor software changes in a FORTH-based microprocessor data system for the instrument.
Axial introduction of laser-desorbed ions into a quadrupole ion trap mass spectrometer
Analytical Chemistry, 1992
Pulsed infrared laser desorption is accomplished with a quadrupole Ion trap by means of a fiber optic interface. The fiber optic probe lo located external to the ion trap device, and desorbed ions pats through the holm in one end-cap electrode and are trapped. This new method allows desorption and ionization by gabphase catlon attachment of biologically relevant molecules, including Gramicidin S which has a molecular weight of 1141. Trapping lo mort effective by uslng a hlgh helium buffer gas pressure (1 1 mlorr), a long storage Way (150 ms) prlor to detection, and a low rl trapping potential (350-650 V ,) during the desorption pulse. Ion-moiecuie reactions of neutrals with trapped laserdosorbed ions are also demonstrated. Aikaiknetai catlons or halide anlons may be formed by desorption of aikalknetai halide salts, and these ions may be selectively stored for subsequent attachment to volatile organics, such as polyethers. Additlonally, transitionmetal ions desorbed at higher laser power densities undergo selectlve attachment to aromatic substrates such as naphthalene.
The Quadrupole Ion Trap Mass Spectrometer—A Small Solution to a Big Challenge
Analytical Biochemistry, 1997
Innovations in ion trap mass spectrometry have ex-those of standard amino acid derivatives. The technique requires a free amino terminus and a homoge-tended the applicability of this technique to the analysis of biological molecules. This tutorial review dis-neous sample. Typical sample quantities are at the 1to 10-pmol level (1). Posttranslational modifications to cusses basic ion trap theory and provides practical examples of how the theory is used to perform different amino acid residues cause anomalous retention times
Operation of a quadrupole ion trap for particle beam LC/MS analyses
Analytical Chemistry, 1993
Several operational modes of the quadrupole ion trap mass spectrometer (QITMS) were investigated to perform particle beam (PB) LC/MS analyses. The PB interface was directly coupled to a QITMS without the use of an external ion source; vaporization of the particle beam and ionization by electron ionization (EI) were accomplished within the ion trap. Ions from residual LC solvent initially caused space charging and a significant extent of chemical ionization (CI), which degraded the quality of E1 mass spectra. Ejection of solvent ions prior to mass analysis minimized both space charging and CI, which allowed acquisition of E1 spectra that compared favorably to E1 spectra obtained from pure samples vaporized off of a solids probe and to library E1 spectra. Isocratic LC/PB/QITMS analyses for several pesticides show lower limits of detection (LODs) than those reported for LC/PB/MB analyses on PB systems using quadrupole mass analyzers. Typically nonlinear calibration curves are produced, although linear calibrations have been observed for some analytes.
High resolution on a quadrupole ion trap mass spectrometer
Journal of the American Society for Mass Spectrometry, 1991
By using a modified ion trap mass spectrometer, resolution in excess of 30,000 (FvVHM) at m I z 502 is demonstrated. The method of increasing resolution in the ion trap mass spectrometer operated in the mass-selective instability mode depends on decreasing the rate of scanning the primary radio frequency amplitude as well as USirlg resonance ejection at the appropriate frequency and amplitude. A theoretical basis for the method is introduced. (J Am Soc Mass Spectrom 1991, 2, 198-104) ,.,.,he capabilities of quadrupole ion traps have Address reprint requests to Jae c. Sell war'bc, Finnigan MAT,