Investigation of ion transfer efficiency through multi-channel capillaries for a Desorption Electrospray Ionization (DESI) interface

Abstract

Desorption Electrospray Ionization (DESI) coupled with mass spectrometry (MS) is an efficient imaging technique for obtaining the spatial distribution of molecular species from a surface. In this study, we experimented with different capillary geometries to maximize the signal intensity of analyte peaks obtained through DESI by improving the temperature uniformity throughout the capillary flow. Multi-channel capillaries were discovered to be more sensitive to temperature and less prone to turbulence under certain conditions when compared to single channel capillaries. A multiple regression analysis reveals the significance of the surface-area-to-volume ratio, inlet-to-outlet area ratio, and the interaction of these main effects with temperature. This study illustrates the complex tradeoff between desolvation and ion loss, thereby providing a general guideline to instrumentation design for the purpose of maximizing signal intensity of the MS.