Coupling Electrochemistry with Probe Electrospray Ionization Mass Spectrometry.

A new coupling of electrochemistry with mass spectrometry (MS) using probe electrospray ionization (PESI) is presented. Due to the high salt tolerance of PESI, the detection of electrochemical reaction products in room-temperature ionic liquids (RTILs) is realized for the first time. Furthermore, PESI-MS allows the analysis of electrochemical reaction products on different or multiple electrode surfaces. In addition, peptides and proteins fractionated through isoelectric focusing (IEF) in the presence of an external electric field can also be directly analyzed by using PESI-MS, suggesting a new and rapid characterization means for the IEF technique. This study reveals the versatility of EC/PESI-MS, which could have an impact in electrochemistry and bioanalysis fields.