Mass-analysis method and mass-analysis apparatus
US8097844B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 23, 2006 |
| Grant date | Jan 17, 2012 |
| Priority date | — |
| Expiry date | Nov 13, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J49/424
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Among various ions introduced into an ion trap 1, those ions which are within a predetermined mass range including the mass-to-charge ratio of an objective ion are selected. Then, the frequency of a capturing voltage is set so that the objective ion will be captured with a high q-value, and a CID gas is introduced into the ion trap 1. An excitation voltage corresponding to the mass-to-charge ratio of the objective ion is applied to end-cap electrodes 3 and 4 to cause an oscillation of the objective ion and help dissociation of the ion by CID. The high q-value leads to a high dissociation efficiency. The application of the excitation voltage is discontinued before the low-mass ions produced by CID totally dissipate. Simultaneously with this operation, or slightly delayed therefrom, the frequency of the capturing voltage is switched so that the q-value will be lowered. Although the high q-value allows the low-mass product ions to easily dissipate during the CID process, they can be captured within an ion-trapping space 5 since the q-value is lowered when those ions still remain there. Thus, measurement of low-mass product ions can be simultaneously achieved with improvement of dissoc…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.