Ion Trajectories in Quadrupole Mass Filters for a and q Parameters Near the Stability Region Tip
✍ Scribed by Damaschin Ioanoviciu
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 254 KB
- Volume
- 11
- Category
- Article
- ISSN
- 0951-4198
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✦ Synopsis
The ion motion inside quadrupole mass filters is described for a and q values close to those corresponding to the stability region tip. The conventional solutions involving the constant-amplitude series of sine functions, which vanish for the stability region tip, were replaced by Mathieu functions of the second kind. Trajectories are completely defined as functions of time, or of the longitudinal coordinate, by the initial conditions, including the radiofrequency phase when the ion enters the filter, by the operating line slope and the value of q. For the stability region tip, ions with trajectories in a 12.5 cm long filter with 5.6 mm interelectrode distance, starting with x = 2.2 mm (y = 1.41 mm) or making an angle α x = 0.35° (α y = 0.48°), are predicted to be successful in traversing the quadrupole and to thus be detected.