Waters Micromass ZQ 2000, Руководство оператора, Страница: 91 / 133

Routine Maintenance 91
5
5.2.6 Cleaning the APCI Probe Tip
Clean the APCI probe tip when buffer residue accumulates on the probe tip or when signal
intensity weakens.
1. Stop the liquid flow.
2. Open the source enclosure cover, and close the isolation valve ( Figure 5-10 ). Close
the source enclosure cover, reattaching its clip fasteners.
3. Click (API Gas) in the Tune window to start nitrogen flowing.
4. Adjust the nitrogen flow to approximately 650 liters per hour, as indicated by the
Tune window (
Figure 3-3 ) desolvation gas meter. Set the APCI probe heater
temperature to 650 °C, and press Enter .
5. Click the Operate icon, and wait 10 minutes with the APCI probe heater at 650 °C.
This will remove any chemical contamination from the probe tip.
5.2.7 Cleaning and Replacing the Corona Discharge Needle
Clean or replace the needle if it looks corroded or black, and you have noticed decreased
signal intensity.
Required Materials
• Lint-free cotton or powder-free nitrile gloves
• Lapping film
• HPLC-grade methanol
• Lint-free tissue
Procedure
To clean and replace the corona discharge needle ( Figure 5-9 ):
1. Remove the center panel from the front of the detector ( Figure 5-8 ).
2. Remove the two knurled thumbscrews from the top of the probe.
3. Disconnect the front panel gas and electrical connections ( Figure 5-8 ).
4. Open the source enclosure cover.
5. Remove the corona discharge needle from the source, pulling it straight out.
STOP
Attention: Wear lint-free cotton or powder-free nitrile gloves for the rest of
the cleaning procedure.
Caution: The inner surfaces of the source enclosure and its constituent
components are hot.