A perspective on the theoretical and numerical aspects of Ion Mobility Spectrometry

Abstract

Ion Mobility Spectrometry (IMS) has become a ubiquitous analytical technique, in particular when used as an orthogonal technique to Mass Spectrometry (MS). As separations of ions in the gas phase become more precise, the need to provide a suitable theory that explains the observed differences is apparent. While the theory exists, much of it is obscured due to the difficulty of the equations and the approximations to the solution. This work explores some of the more useful theoretical approaches to IMS while making use of a full Monte Carlo simulations algorithm to provide some pedagogical examples that characterize the reasons behind the different theoretical approaches, and whether they need to be used for a particular calculation. To improve the existing theory, reliable empirical data is required. For such reason, an appropriate labeling system for mobility is proposed here requiring that at least the temperature, gas, electric field, and instrument employed are provided and which is an extension of the previous protocol.