Atmospheric pressure plasma assisted CW laser desorption source for imaging mass spectrometry applications

Abstract

We report a high spatial resolution ambient mass spectrometry (AP-MS) system that allows us to sensitively image live tissues at ambient environment. The method is based on an efficient desorption process by continuous wave (CW) laser assisted with nanoparticles and a subsequent ionization step by applying nonthermal helium plasma. The desorption of molecules from the tissues was found to be greatly enhanced by the strong photothermal effect of gold nanoparticles and CW laser. The subsequent ionization process with nonthermal atmospheric helium plasma jets enabled production of sufficient amounts of molecular ions of important molecules from live hippocampal tissues of an adult mouse. Combining the AP-MS with microscopic sample scanning, MS imaging with micrometer spatial resolution could be obtained with a sampling depth down to several tens of µm. This technique enables the advancement of AP-MS imaging technology into future clinical applications.