Optimize The Apci Probe - AB Sciex 4500 Series System User's Manual

Turbo V™ Ion Source User Reference
• Use the lowest IonSpray voltage possible without losing signal. Focus on signal-to-
noise and not just signal.

Optimize the APCI Probe

Optimize performance by injecting a known compound and monitoring the signal of the known
ion. Adjust the parameters to maximize the signal-to-noise ratio.
Table A-3 Typical Values for Optimizing the APCI Probe
Parameter
Probe X-axis position
Probe Y-axis position
The optimal X-axis position is within 0 mm to 2 mm on either side of the orifice.
The optimal probe Y-axis position is within 3.0 mm to 7.0 mm of the orifice.
Warm up the APCI Probe
Caution: Potential Equipment Damage: If the LC system connected to the mass
spectrometer is not controlled by the Analyst software, then do not leave the mass
spectrometer unattended while in operation. The LC system can flood the ion source
housing when the mass spectrometer goes into Standby mode.
1. On the Source/Gas tab in the Tune Method Editor, in the Curtain Gas (CUR) field,
type 20.
Operate the APCI probe with the highest Curtain Gas flow rate possible without a
noticeable signal drop.
2. In the Ion Source Gas 1 (GS1) field, type 20.
3. In the Temperature (TEM) field, type 400.
4. Before starting the sample flow, let the ion source warm up for 30 minutes or until the
ion source housing is warm to the touch.
The 30-minute warm-up stage prevents solvent vapors from condensing in a cold
probe.
5. Turn on the pump.
6. Wait until the APCI probe reaches a temperature at which the solvent mist is cleared
from the ion source housing (about 10 minutes).
Adjust the Corona Discharge Needle
When using the APCI probe, make sure that the corona discharge needle is pointing toward the
orifice.
WARNING! Electrical Shock Hazard: Follow this procedure to avoid contact with
the high voltages applied to the corona discharge needle and the curtain plate.
1. Use the slotted screwdriver to rotate the plastic screw on the top of the needle.
4500 Series of Instruments
114 of 142
Typical value
5 mm
5 mm
Operational range
Scale 0 mm to 10 mm
Scale 0 mm to 13 mm
System User Guide
Document Number: D5030863 A