Dual-Mode Operation - Waters Xevo TQD Operator's, Overview And Maintenance Manual

Dual-mode operation

Dual-mode operation enables rapid switching between APPI and APCI
ionization modes and allows high-throughput operations (for example, for
sample screening).
You replace the standard corona pin with a specially shaped APPI/APCI
corona pin, so that the APPI lamp holder can be advanced into the source for
dual operation.
When the source is configured for dual operation in APCI mode, current is
applied to the corona pin, but the repeller electrode is inactive.
Dual operation in APCI mode:
IonSABRE II probe
Sample cone
Photons from the UV lamp
When the source is configured for dual operation in APPI mode, the corona pin
is inactive, and a voltage is applied to the repeller electrode.
Dual operation in APPI mode:
IonSABRE II probe
Sample cone
Photons from the UV lamp
Repeller electrode inactive
Corona pin with current applied
Repeller electrode with
voltage applied
Corona pin inactive
Combined APPI/APCI source 3-11