Patent ID: 6998608

Claim:
An apparatus for separating ions in the gas phase, comprising: a high field asymmetric waveform ion mobility spectrometer comprising two electrodes defining an analyzer region therebetween, the two electrodes disposed in a spaced apart arrangement for allowing ions to propagate therebetween and for providing an electric field within the analyzer region resulting from the application of an asymmetric waveform voltage to at least one of the two electrodes and from the application of a compensation voltage to at least one of the two electrodes, for selectively transmitting a first type of ion along an average ion flow path within the analyzer region at a given combination of asymmetric waveform voltage and compensation voltage; and, an optical port disposed adjacent to a portion of the analyzer region other than a portion including an origin of the average ion flow path, the optical port formed of a light transmissive material other than a gas, which material is transmissive to light within a predetermined range of wavelengths for supporting the propagation of light having a wavelength within the predetermined range of wavelengths between the analyzer region and a region that is external to the analyzer region.