Title:
イオントラップ質量スペクトロメータに使用する質量走査方法
Document Type and Number:
Japanese Patent JP4173208
Kind Code:
B2
Abstract:
An improved method of using an ion trap mass spectrometer is disclosed. According to the method an asymmetrical trapping field is applied to the trap (10). Preferably, the asymmetrical trapping field comprises a quadrupole field and a dipole field having the same frequency. In addition, higher order trapping field components, such as hexapole or octopole fields, may also be included, and the electrodes of the ion trap (10) can be shaped to introduce such higher order field components. The effect of the asymmetrical trapping field of the present invention is to cause the center of the trapping field to be displaced from the mechanical center of the ion trap (10). A supplemental quadrupole field is then applied to the ion trap (10), the center of the supplemental quadrupole field being located at the mechanical center of the trap, i.e., it is displaced from the center of the trapping field. The supplement quadrupole field and the trapping field may be viewed as forming one combined field which acts upon the ions in the trap (10). The combined field is then scanned to cause ions of differing masses to be resonantly ejected from the ion trap (10) in sequential mass order. Preferably, the combined field is scanned by scanning the voltage of the trapping field. Preferably, the supplemental field is set to have a frequency which is two-thirds of the trapping field frequency and is phase locked with the trapping field frequency.
Inventors:
Gregory Jay Wealth
Mingda Wang
Edward G. Marcette
Mingda Wang
Edward G. Marcette
Application Number:
JP6222997A
Publication Date:
October 29, 2008
Filing Date:
February 28, 1997
Export Citation:
Assignee:
Varian, Incorporated
International Classes:
G01N27/62; H01J49/42; H01J49/04
Domestic Patent References:
| JP6237861A |
Foreign References:
| US5291017 | ||||
| US5298746 | ||||
| US4882484 |
Attorney, Agent or Firm:
Inaoka cultivation
Mio Kawasaki
Mio Kawasaki