Measuring the Resolving Power of Ion Mobility Spectrometers

Ion mobility spectrometry peak width data are fitted by a least-squares procedure to a semiempirical model having three adjustable parameters. Peaks are wider than contributions from initial pulse width and diffusion predict, and it is suggested that the additional width is due mainly to electric field inhomogeneity and Coulombic repulsion. The effects of operating conditions and instrument dimensions on resolving power are discussed. It is proposed that increased inhomogeneity of the electric field results in lower measured mobility values, as well as lower resolving power