Waters Quattro Premier XE, Operator'S Manual, Page: 18 / 86

1-4 APPI, APCI, and Dual APPI/APCI Modes
Dual APPI/APCI mode
Dual APPI/APCI mode enables rapid switching between ionization modes, and
allows high throughput (for example, for sample screening).
The standard corona pin is replaced with a specially-shaped dual APPI/APCI
corona pin, so that the APPI lamp holder can be advanced into the source for
dual APPI/APCI 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
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
Sample cone
APCI probe
Photons from the UV lamp
Repeller electrode inactive
Dual APCI/APPI corona pin with
current applied
Sample cone
APCI probe
Photons from the UV lamp
Repeller electrode with
voltage applied
Dual APCI/APPI corona
pin inactive