Waters 2475, Operator'S Manual, Page: 147 / 228

Inspecting, cleaning, and replacing the flow cell 4-5
Inspecting, cleaning, and replacing the flow cell
A dirty flow cell can cause baseline noise, decreased sample energy levels,
calibration failure, and other problems. This section provides information
about the following procedures:
• Flushing the flow cell
• Removing and cleaning the flow cell
• Replacing the flow cell
Flushing and passivating the flow cell
Flush and passivate the flow cell when you suspect that it is dirty.
To flush and passivate the flow cell:
1. Discontinue the flow of mobile phase.
2. Remove the column.
3. Attach tubing from the detector to the injector outlet (from which the
column has been removed).
4. Flush the mobile phase from the detector with a miscible solvent and
water (unless the mobile phase is miscible with water).
5. Flush the detector with HPLC-quality water to remove contaminants
from the flow path.
6. Pump 6 N nitric acid through the flow cell to clean and remove any
accumulated oxides from the internal pathways (passivation).
7. Flush with HPLC-quality water until the cell is pH-neutral.
8. Reattach the column.
9. Resume mobile phase flow.
Requirement:
Use an intermediary solvent if you are using a mobile
phase that is not miscible with water.