Method and apparatus for ejecting ions from a quadrupole ion trap
US6900433B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Nov 29, 2001 |
| Grant date | May 31, 2005 |
| Priority date | — |
| Expiry date | Nov 29, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J49/427
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method for ejecting ions from a quadrupole ion trap includes creating a digital control signal, using the digital control signal to control the timing of a switch unit to generate a time-varying rectangular wave voltage, supplying the rectangular wave voltage to the ion trap to trap ions in a predetermined range of mass-to-charge ratio, and varying the duty cycle of every nth wave of the rectangular wave voltage (where n is an integer greater than 1) to cause ejection of ions having a predetermined mass-to-charge ratio. The method can be used for analysis of mass-to-charge ratio by adjusting the frequency of the rectangular wave voltage to select a starting point for scanning mass-to-charge ratio, and then varying the frequency while the duty cycle is being varied to cause ejection of trapped ions, in sequence, according to mass-to-charge ratio.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.