LASER-ASSISTED REFLECTRON TIME-OF-FLIGHT MASS-SPECTROMETRY

Pulsed-mode laser assisted ionization schemes are extensively used in connection with time-of-flight mass spectrometric techniques, particularly when large-mass, thermally labile molecules i.e. biomolecules, proteins, and DNA have to be analysed. Along with the high resolution accomplished with the introduction of the reflector fields, these techniques have received considerable attention, in particular due to their ability to record a mass spectrum over the whole mass range with each single pulse. It is also important to note that the ionization volume (the space in which ions are created) can be considerably larger than in static mass Spectrometers and with essentially unlimited mass-range. Furthermore, the sensitivity of laser-assisted reflectron time-of-flight mass spectrometry can almost reach its physical limit (a few atoms or molecules). Many modifications of laser assisted reflectrons have been developed. The key differences reside, on the one hand in the methods employed to focus the times-of-flight of the ions on the detector, and on the other hand with the specific sources used. One can expect to witness in the near future an ever increasing interest in these techniques with a wide range of new applications in fundamental and applied science or technologies such as materials science, analytical chemistry, pharmacology, biochemistry and genetics, to cite only a few.