Method and apparatus for scanning an ion trap mass spectrometer in the resonance ejection mode
US5572025A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 25, 1995 |
| Grant date | Nov 5, 1996 |
| Priority date | — |
| Expiry date | May 25, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J49/429
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method of operation of an ion trap mass spectrometer having a ring electrode and pair of end-cap electrodes in a resonance ejection mode is disclosed. The method includes producing ions from a plurality of biomolecules, applying a trapping RF voltage to the ring electrode, applying an excitation voltage to the end-cap electrodes, scanning the trapping RF voltage in order to sequentially eject the ions, controlling a ration of the amplitude of the trapping RF voltage to the amplitude of the excitation voltage in order that the ratio is generally constant, and determining a ratio of mass to charge of the ejected ions. In one embodiment, a feedback voltage which is proportional to the trapping RF voltage is sensed, and the amplitude of the excitation voltage is controlled as a function of the amplitude of the feedback voltage. In another embodiment, a first value related to the amplitude of the trapping RF voltage and a second value, which is proportional to the first value and related to the amplitude of the excitation voltage, are determined. The amplitude of the trapping RF voltage is modulated employing the first value and the amplitude of the excitation voltage is modulated emp…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.