| 摘要 |
A method of fragmenting ions is disclosed comprising providing a linear ion trap comprising: a first electrode set 4a, preferably in the form of a pre-filter quadrupole; a second electrode set, preferably an analytical quadrupole 4b, arranged downstream of the first; and a third electrode set, preferably a post-filter quadrupole 4c, arranged downstream of the second. A potential difference between at least some of the electrodes making up the first and second, and/or the second and third electrode sets is varied in order to accelerate ions and cause them to fragment through collisions with a gas provided within the ion trap. Preferably, the ions are accelerated into either the pre-filter or post-filter quadrupole devices to collide with gas flowing out of an upstream ion source (2, Fig. 1) or downstream collision cell 6 respectively. A pulsed gas source may also be used in order to temporarily increase the pressure within either the pre-filter or post filter section of the ion trap. |
