Fundamental considerations for the application of miniature Ion mobility spectrometry to field analytical applications

Ion mobility spectrometry (IMS) is a popular field analyzer. The reason for its popularity is its small size, its sensitivity, and the amount of information contained in the ion mobility spectrum. Several research groups are working on smaller IMS cells using microelectromechanical systems (MEMS) technology. New principles of operation will be needed to achieve this goal. The theory supporting the development of the radio frequency (RF) IMS is described. RF-IMS separates ions by applying an asymmetric RF field across two parallel plates and passing the ions through the separator. The performance of the device no longer depends on a simple linear relationship between the drift velocity and an electric field, but rather on a nonlinear relationship between these parameters. Consequently, a more detailed momentum-transfer theory is needed. The required theory is developed and applied to the interpretation of experimental data here. The importance of using momentum transfer theory in combination with the continuity equation is demonstrated. © 2000 John Wiley & Sons, Inc. Field Analyt Chem Technol 4: 255–267, 2000