Laser Applications in Chromatography
Light amplification by stimulated emission of radiations (Lasers) becomes more and more popular in analytical applications. In analytical chromatography, laser is mainly used for analyte excitation in detectors and for analyte desorption and ionization, which are needed for sampling and for coupling chromatography to mass spectrometry. Raman spectroscopy became a powerful method for detection in various chromatographic techniques, as it also allows gaining structural information. Raman scattering is affected by the vibrational energy levels of the analyte; therefore, Raman spectroscopy provides significant molecular information. In traditional Raman spectroscopy, the signals are severely interfered by fluorescence, because the fluorescence emission is broad and often of a quantum yield that is higher than that of Raman scattering. The first realizations in Raman detection in chromatography were already made in the 1980s. A very interesting approach has been proposed by Joon Lee et al. for separation of metal ions on a surface-enhanced Raman active medium.