Electrochemical Push–Pull Scanner with Mass Spectrometry Detection

This manuscript presents a push-pull electrochem. scanner able to image reactivity of initially dry surfaces by scanning electrochem. microscopy (SECM) and to probe mols. present or generated at the surface by mass spectrometry (MS). The proof-of-concept is demonstrated by coupling SECM with matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) for imaging latent human fingerprints, which had been in contact with picric acid used here as a model explosive. The push-pull electrochem. scanner also was coupled with electrospray ionization mass spectrometry (ESI-MS) to assay the activity of surface spotted enzymes. These exptl. studies are complemented by 3-dimensional finite element simulations solving Navier-Stokes and diffusion-convection differential equations to optimize the coupling between SECM imaging and mass spectrometry detection.