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.