LASER-DESORPTION MASS-SPECTROMETRY OF A LEVITATED SINGLE MICROPARTICLE IN A QUADRUPOLE ION-TRAP

Techniques for microparticle levitation in a vacuum ion trap and switching of electric fields from particle levitation mode to ion trapping mode prior to laser desorption/ionization and mass analysis are described. Single microparticles of rubidium chloride and copper oxide with a size of similar to 20 mu m have been levitated in a quadrupole ion trap and ablated by a Nd/YAG laser (532 nm) followed by ion mass analysis in the same ion trap. The mass spectrum of an organic sample (tetraphenylphosphonium bromide) that was deposited on the surface of a SiC microparticle has been similarly measured.