Hot electron transfer promotes ion production in plasmonic metal nanostructure assisted laser desorption ionization mass spectrometry.

Plasmonic metal nanostructures have been used as effective materials for enhancing the laser desorption ionization (LDI) efficiency in mass spectrometry analysis. But the ionization mechanism and the origin of initial charges have not been fully understood yet. Here we provided experimental evidence showing that the hot electron transfer in localized surface plasmon resonance (LSPR) plays a key role in ionizing molecules during the LDI process.