Patent ID: 7223967

Claim:
A high field asymmetric waveform ion mobility spectrometer having a side-to-side electrode geometry, comprising: an inner electrode having a length and an outer surface that is curved in a direction transverse to the length; and, an outer electrode having a length and a curved inner surface, a portion of the length of the outer electrode overlapping a portion of the length of the inner electrode so as to provide an analyzer region therebetween, the outer electrode including an ion inlet for introducing ions from a source of ions into the analyzer region and an ion outlet for extracting ions from the analyzer region, the ion inlet and the ion outlet disposed on opposing sides of the outer electrode, Characterized in that: at least one of the inner and outer electrodes is shaped such that a width of the analyzer region in the vicinity of the ion outlet is other than a width of the analyzer region in at least one other region.