2. General characteristics of current LC-MS couplings

Two interface levels are used in all recent LC-MS systems. Interface 1 (see Chromatographic couplings with mass spectrometry I [P 1 490] , § 4.6, figure 7) comprises a nebulizer and a generator of ions from the solutes in the chromatographic eluent, based on different ionization methods APCI, APPI, ESI... and mounted on an atmospheric pressure chamber (API). Interface 2 combines, in line, a sampling zone towards the vacuum and an ion guidance optic towards the mass spectrometer analyzer. This analyzer is more or less complex and powerful, depending on the instrument model, and...