The present invention enhances the laser desorption of biological molecular ions
from surfaces by creating a surface localized MALDI particle matrix by ion implantation
of low energy ionized clusters (gold, aluminum, etc.) or chemically derivatized
clusters into the near surface region of the sample. MALDI analysis of the intact
biomolecules on the surface or within a narrow subsurface region defined by the
implantation range of the ions can then be performed by laser desorption into a
mass spectrometer or, in a preferred embodiment, into a combined ion mobility orthogonal
time of flight mass spectrometer.