Automated sampling and imaging of analytes separated on thin-layer chromatography plates using desorption electrospray ionization mass spectrometry.

Modest modifications to the atmospheric sampling capillary of a commercial electrospray mass spectrometer and upgrades to an in-house-developed surface positioning control software package (HandsFree TLC/MS) were used to enable the automated sampling and imaging of analytes on and within large area surface substrates using desorption electrospray ionization mass spectrometry. Sampling and imaging of rhodamine dyes separated on TLC plates were used to illustrate some of the practical applications of this system. Examples are shown for user-defined spot sampling from separated bands on a TLC plate (one or multiple spots), scanning of a complete development lane (one or multiple lanes), or imaging of analyte bands in a development lane (i.e., multiple lane scans with close spacing). The post data acquisition processing and data display aspects of the software system are also discussed.