Abstract
The effects of surface scanning mode (raster vs. unidirectional scanning), and the constancy of spray tip-to-surface and atmospheric sampling interface capillary-to-surface distances on chemical image quality using desorption electrospray ionization mass spectrometry were investigated. Unidirectional scanning was found to provide a spatially and a quantitatively more precise chemical image of the surface as compared to raster scanning. Maintaining constant spray tip-to-surface and atmospheric sampling interface capillary-to-surface distances during an imaging experiment was found to also be critical. An automation process was implemented using a custom image analysis software (HandsFree Surface Analysis�) to keep these distances constant during the surface sampling experiment. Improved chemical image quality afforded through this software control was illustrated by imaging printed objects on normal copy paper.
