Analytical Innovations: Development And Applications Of Atmospheric Pressure Laser Ionization (Apli)
A new method for atmospheric pressure ionization for LC and GC / mass spectrometry is reported. The atmospheric pressure laser ionization (APLI) is introduced as a powerful addition to the existing AP ionization techniques, in particular atmospheric-pressure chemical ionization (APCI), electrospray ionization (ESI) and atmospheric-pressure photoionization (APPI). APLI uses the step-wise two-photon ionization in contrast to the one-step VUV ionization process in APPI. The two-photon ionization strongly enhances the selectivity of the ionization process and the high photon flux during an ionization event drastically increases the sensitivity for non-polar compounds over that of APPI. The differences in the ionization will be discussed. The application of APLI investigations of PAH' s, hetero PHA's and halogenated polymers is presented. Furthermore, the combination of APLI with ESI and with gas chromatography opens up an extensive field of applications. In particular the GC/APLI combination provides a very selective and sensitive tool for the measurement of non-polar compounds. The introduction of REMPI labels to polar substances is used to demonstrate one possible application for this class of compounds.
KeywordsMass spectrometry atmospheric pressure ionization REMPI atmospheric pressure laser ionization (APLI) polycyclic aromatic hydrocarbons ESI-APLI GC-APLI APLI-labels
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