SELECTIVE IONIZATION FOR ELEMENTAL ANALYSIS WITH AN ION-TRAP MASS-SPECTROMETER

The ion storage capacity (<10(6)) of ion trap mass spectrometers (ITMS ) can sometimes limit the ability to analyze trace components in compl ex mixtures. We demonstrate here that resonant laser ablation (RLA) ca n offer a degree of selectivity in the ionization process, thus allowi ng the preferential accumulation of analyte ions in the trap. Selectiv ities of 75 and 50, for chromium and iron, respectively, are reported here for RLA of stainless steel in an ITMS. We offer suggestions to im prove both the selectivity and the ionization efficiency, relative to the results reported here.