Electrospray mass spectrometry of undiluted ionic liquids

Ionic liquids have been analyzed in undiluted form using electrospray mass spectrometry (ES-MS); results indicate that signal-to-noise ratios for minor constituents are comparable to those observed in conventional, diluted ES-MS and that this approach could be readily applied for mass spectrometric analysis of ionic liquids and ionic impurities/additives dissolved therein, especially those that are solvent reactive.