Resonance-Enhanced Multiphoton Ionization Mass Spectrometry (REMPI-MS): Applications for Process Analysis

Process analysis is an emerging discipline in analytical sciences that poses special requirements on analytical techniques, especially when conducted in an online manner. Mass spectrometric methods seem exceedingly suitable for this task, particularly if a soft ionization method is applied. Resonance-enhanced multiphoton ionization (REMPI) in combination with time-of-flight mass spectrometry (TOFMS) provides a selective and sensitive means for monitoring (poly) aromatic compounds in process flows. The properties of REMPI and various variations of the ionization process are presented. The potential of REMPI for process analysis is highlighted with several examples, and drawbacks of the method are also noted. Applications of REMPI-TOFMS for the detection and monitoring of aromatic species in a large variety of combustion processes comprising flames, vehicle exhaust, and incinerators are discussed. New trends in technical development and combination with other analytical methods are brought forward.