Laser microprobe mass spectrometry: Possibilities and limitations

Laser microprobe mass spectrometry (LMMS) offers a great potential for inorganic analysis and speciation as well as for organic structural characterization. This remarkable flexibility makes the results critically dependent on the experimental conditions, however, so an exact description is hard to achieve, since inaccessible local parameters are involved. The paper deals in detail with this aspect, which is often neglected but remains essential for making LMMS acceptable as analytical tool. Our methods of procedure are presented in the context of instrumental aspects and experimental evidence. Tentative hypotheses for desorption and ionization in LMMS provide an adequate framework for interpreting results consistently. Selected examples illustrate the potential gained from our experimental procedure as well as the limitations imposed. For organic compounds, analysis of pure products and simple mixtures, and microprobe applications are highlighted. Improved differentiation of inorganic compounds is also shown.