Waters Micromass ZQ 2000, Operator'S Manual

Page: 49 / 133

Tuning in APCI Mode 49
3
3.3.2 Installing the Tee Fitting
To optimize APCI peaks, temporarily install a tee fitting to merge the sample flow from the
syringe pump with the solvent flow from an HPLC pump. The combined sample/solvent
stream flows into the probe (
Figure 3-6 ).
Figure 3-6 Combined Flow into the Tee
1. Connect the HPLC pump tubing to injector port 2 (see Figure 2-7 for port positions).
2. Connect the capillary from the syringe pump to one of the tee’s three ports.
3. Connect a 1/16-in. OD × 0.007 in. ID × 1 M tube between injector port 3 and a
second tee port.
4. Connect another 1/16-in. OD × 0.007 in. ID × 1 M tube from APCI probe to the tee’s
third port.
3.3.3 Specifying Parameters on the APCI+ Source Page
Table 3-4 describes the APCI+ Source page parameters.
Table 3-4 APCI+ Source Page Parameters
Parameter Description
Corona Affects sensitivity. The amount of current required depends on
the polarity of both the compound and mobile phase.
Optimize when mobile phase is present.
APcI Probe Temp Affects sensitivity. Start at 650
o
C and reduce in 50
o
steps,
allowing time for stabilization to take place before reading.
Optimize while mobile phase is flowing.
Desolvation Gas flow rate usually affects signal intensity only marginally.
Nevertheless, adjusting it can suppress chemical background
noise.
Cone Gas Gas flow rate can minimize formation of solvent adducts.
HPLC Pump Flow
From Injector Port 3
Combined Flow
into Probe
Syringe Pump
Flow