LASER SPECTROSCOPY ON ORGANIC-MOLECULES

Various laser spectrometric methods have been developed until now. Esp ecially, laser fluorometry is most sensitive and is frequently combine d with a separation technique such as capillary electrophoresis. For n on-fluorescent compounds, photothermal spectrometry may be used instea d. A diode laser is potentially useful for practical trace analysis, b ecause of its low cost and long-term trouble-free operation. On the ot her hand, monochromaticity of the laser is essential in high-resolutio n spectrometry, e.g. in low temperature spectrometry providing a very sharp spectral feature. Closely-related compounds such as isomers can easily be differentiated, and information for assignment is obtained f rom the spectrum. Multiphoton ionization mass spectrometry is useful f or soft ionization, providing additional information concerned with mo lecular weight and chemical structure. A short laser pulse with a suff icient energy is suitable for rapid heating of the solid surface. A ma trix-assisted laser desorption/ionization technique is recently employ ed for introduction of a large biological molecule into a vacuum for m ass analysis. In the future, laser spectrometry will be developed by a combination with state-of-the-art laser technology. In the 21st centu ry, new laser spectrometry will be developed, which may be based on re volutionary ideas or unexpected discoveries. Such studies will open ne w frontiers in analytical laser spectroscopy.