User guide

Multimode Source for 6100 Series Single Quad LC/MS User Guide 45
Reference 3
Benefits of a multimode source
• Permits analysis of fast-eluting peaks
• Operation at flow rates used for high-throughput analysis without splitting
• Operation at lower flow rates for higher-sensitivity analysis
The design uses a single nebulizer through which the LC effluent flows. You do
not need to switch back and forth between APCI and ESI modes. While this
option will be available, the great value of the source is its ability to produce
APCI and ESI generated ions simultaneously. This ability increases the
effective duty cycle of the mass spectrometer. Another key feature is the much
greater operational flow rate that is available in this design.
Mixed mode operation is generally a balance between optimal ESI and APCI
conditions. Changing the vaporizer temperature, the nebulizer pressure, and
the corona current alters the balance between the ionization modes.
Ionization Mode Polarity
APCI positive
APCI negative
APCI fast switching
ESI positive
ESI negative
ESI fast switching
Multi-Mode positive
Multi-Mode negative
Multi-Mode fast switching
Parameter adjustment APCI response in mixed mode
generally
ESI response in mixed mode
generally
Higher vaporizer temperature Increases Stays the same
Higher nebulizer pressure Decreases Increases
Higher corona current Increases Decreases