Surface-enhanced transmission mode desorption electrospray ionization: increasing the specificity of ambient ionization mass spectrometric analyses.

Fabrication and utilization of mesh materials specifically designed to capture analytes from solution facilitates the direct coupling of affinity capture and ambient ionization mass spectrometry via surface-enhanced transmission mode desorption electrospray ionization (TM-DESI). Incorporation of photolabile groups within the linkage between the mesh surface and the covalently modified reactive probe affords facile release of mass tagged analytes directly to mesh surfaces that have been rinsed free of matrix interferences. The approach introduces increased specificity to the already rapid TM-DESI analysis technique, resulting in a powerful tool for high-throughput screening of targeted analytes. Specific capture of thiols is discussed herein, but the surface-enhanced TM-DESI technique can be readily extended to other functional groups by alteration of the capture agent.