Next Generation in Ion Mobility Methods

Quantitative response in IMS is today acceptable in applications where IMS has been successful yet unacceptable compared to other detector technologies, such as flame ionization detectors or MSs. This is limited by kinetics of ion formation at the low end of response and by ion source saturation at the top end of the response curve and by matrix effects. Other technologies, such as electron capture detectors and the ion trap MS, shared a similar history and were engineered free of the limitations. There is no such advancement under way today in IMS. 

The Faraday plate detectors, the mainstay of detector technology in IMS from its inception as a modern analytical method, are seen as robust and effective for field instruments and relatively small ions. Nonetheless, the poor gain and susceptibility to microphonic noise can also be seen as disadvantages. Probably, these worries and wishes are small compared to the fundamental barrier to improved resolving power, which is established with the ion shutter. The Bradbury-Neilson (BN) or Tyndall-Powell (TP) shutters have and will certainly be the method of choice into the foreseeable future for IMS analyzers. The constraint is ambient pressure based. The limitation induced with fleld-mobility-based injections are large, yet no improved solution has been demonstrated. 

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