DEVELOPMENT OF A LASER MICROPROBE FOURIER-TRANSFORM MASS-SPECTROMETERWITH EXTERNAL ION-SOURCE

Laser microprobe mass spectrometry (LMMS) employs focused laser-beam i rradiation of solids and subsequent mass analysis of the ions produced . The technique is suitable for the local analysis of inorganic and or ganic constituents with a spatial resolution in the micrometer range. The Fourier transform mass spectrometer (FTMS) is an analyser of choic e for LMMS because high mass resolution and accurate mass determinatio n can be routinely achieved at adequate sensitivity. This paper descri bes the first LMMS instrument using FTMS with an external ion source. The design considerations and the experimental performance are describ ed with respect to such analytical parameters as spatial resolution an d sensitivity. A comparison between time-of-flight mass spectrometry a nd FT-LMMS for diagnostic analysis of organic molecules is interpreted in terms of the ion formation processes. Finally, the analysis of a s elected integrated circuit evidences the feasibility of local analysis with 2 spatial resolution of 5 mum.