Ultra-soft Desorption Assisted Mass Spectrometry using Picosecond Infrared Laser for the Detection of Ions in the Liquid Surface

To identify the species in liquid surface using mass spectrometry, we must eliminate or reduce interferences during the vaporization or desorption of the species from the liquid surface. It is much more challenging to isolate the ionic, larger species from the liquid surface, because of the frangible structures and the higher solvation energies of those species. Here we demonstrate a new mass spectrometry in which the ionic species at the liquid surface can be desorbed with ultra-soft infrared picosecond laser pulses while the liquid surface is not breached. This laser desorption assisted mass spectrometry is not only a powerful tool to detect the fragile species but also promising to investigate vibrational energy transfer dynamics in the liquid surface.