Waters 2489, Operator'S Manual

Page: 140 / 234

4-6 Maintaining the Detector
4. Pump 100% methanol through the flow cell to clean it internally. Do not
exceed 3447 kPa (34 bar, psi).
5. Pump a strong cleaning solvent, such as isopropanol, through the flow
cell (optional). Do not exceed 3447 kPa (34 bar, psi).
6. Resume pumping mobile phase.
7. Reattach the column.
Tip: Waters recommends renormalizing in 100% water before resuming
analyses.
8. If the flow cell remains dirty or blocked, reverse flush it.
Removing and cleaning the flow cell
If flushing the flow cell is not effective, follow the procedures to remove the
flow cell and inspect for dirty or broken windows or dirty gaskets. Clean and
replace parts if necessary.
Before removing the flow cell assembly, purge the flow cell with nitrogen and
allow it to dry.
To purge the flow cell:
1. Connect the nitrogen supply line to the sample inlet. Route the sample
line to waste.
2. Purge the cell for 25 to 30 minutes at 15 psi to 20 psi.
3. Allow the flow cell to dry completely.
4. Disconnect the detector inlet/outlet tubing from the main column
connection and cap.
Disassembling and reassembling the flow cell
Before you begin
Take the following precautions when disassembling and reassembling the
flow cell:
Caution: If the mobile phase is not miscible in water, first use an
intermediary solvent.