| 摘要 |
Disclosed is a cylindrical geometry FAIMS apparatus with an improved ion inlet designed for efficiently transporting ions in the gas phase into the analyser region of the FAIMS apparatus. Ions are focussed into a region close to the tip (22a) of the inner electrode (22) carrying an asymmetric high voltage waveform and a compensation voltage, rather than colliding with the tip or other members in the vicinity. The focussing takes place in accordance with the ion focussing effect known from high-field asymmetric waveform ion mobility spectrometry (FAIMS). High electric field gradients occur in the vicinity of a tip carrying a voltage, and these high field gradients are used in the instant invention to yield a strong focussing effect. The main improvements lie in decreased ion losses with subsequently increased ion throughput and more sensitive ion detection, and in the increased flexibility in the design and position of ion sources. |
