An Electrohydrodynamic Ion Source for the Mass Spectrometry of Liquids

An electrohydrodynamic ion source has been constructed and attached to a high resolution mass spectrometer. This ionization process is based on the interaction of a conducting liquid surface and an intense electrostatic field. An ion source operating on Ga–In eutectic alloy has produced in excess of 30 μA of ion current. The mass spectra obtained from the Ga–In source provided conclusive proof of the production of singly charged, monatomic ions. In addition the ion source ionized five impurities dissolved in the liquid eutectic.