Electrospray Ionization Mass Spectrometry for Mechanism Analysis of Metal Ion Complexation and Photoionization of Malachite Green Derivatives Incorporating a Crown Ether Moiety

Abstract

Electrospray-ionization mass spectrometry using a photoirradiation interface has been successfully applied to the investigation of metal-ion complexation and photoionization of crowned Malachite Green leuconitrile derivatives in solution. The mass spectrometry clearly showed that the Malachite Green derivatives in their electrically neutral forms can complex metal ions with their crown ether moiety. Ionization of the Malachite Green derivatives to their corresponding cationic forms, accompanied by metal-ion repelling from their crown ether moiety, was detected upon UV-light irradiation. A remarkably different photoionization behavior in various solvents, which is difficult to detect by other analytical techniques, was also found by the mass spectrometry.