Pushing a compact 15 cm long ultra-high resolution drift tube ion mobility spectrometer with R = 250 to R = 425 using peak deconvolution

Abstract

Recently, we have published an analytical model describing the resolution and signal-to-noise-ratio of peaks present in an ion mobility spectrum acquired by a drift tube instrument. Based on this model, we designed a combination of a compact 10 cm long drift tube and a fast transimpedance amplifier achieving a resolution above 180. Here, we present results using an improved drift tube with slightly longer drift length of 15 cm and higher drift voltages, resulting in a resolution of R = 250 for the positive reactant ion peak and R = 230 for the negative reactant ion peak. By applying a deconvolution algorithm based on the Jansson method, a two- to three-fold separation improvement is possible in theory. However, as a larger resolution improvement than the initial resolution loss by diffusion may lead to erroneous results, we limited the resolution enhancement to 70 %, reaching a resolution of R = 425 for deconvolved spectra.