Technical data

Overview 1
Multimode ionization (MMI)
Agilent 6200 Series TOF and 6500 Series Q-TOF LC/MS System Concepts Guide 25
Multimode ionization (MMI)
The multimode source is an ion source that can operate in three
different modes: APCI, ESI or simultaneous APCI/ESI. The
multimode source incorporates two electrically separated,
optimized zones: one for ESI and one for APCI. During
simultaneous APCI/ESI, ions from both ionization modes enter
the capillary and are analyzed simultaneously by the mass
spectrometer.
ESI and APCI are essentially incompatible processes because
each needs its own conditions for aerosol drying and electrical
fields. However, it is possible to form ions simultaneously from
ESI and APCI if the two ionization regions are separated in
space.
Multimode ionization (MMI) is useful for screening of
unknowns, or whenever samples contain a mixture of
compounds where some respond by ESI and some respond by
APCI. In these cases, the multimode source obviates the need to
run the samples twice to accomplish a complete analysis.
Figure 6 Multimode source