Thermo Scientific Accela UV/Vis Plus, Hardware Manual

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3
Routine Maintenance
LightPipe Flow Cell Maintenance
Thermo Scientific Accela UV/Vis Detector Hardware Manual 47
 To clean the flow cell with nitric acid
1. Completely remove the flow cell assembly from the detector housing by following the
procedure in “Removing the LightPipe Flow Cell” on page 42 .
This prevents possible leaks from harming the mechanical and electronic components of
the detector.
2. Ensure that the column is removed from the chromatographic system to avoid column
degradation.
3. Connect the flow cell inlet directly to the chromatographic pump.
4. Flush the flow cell with water.
This prevents a reaction between the last solvent used in the chromatographic system and
the nitric acid solution used to clean the flow cell.
5. Prepare a 20% (v/v) solution of nitric acid in HPLC-grade water.
6. Using the chromatographic pump, pump the nitric acid solution through the flow cell.
7. After you have finished the cleaning procedure and before you return to the
chromatographic solvents, pump another 25 to 40 mL of water through the flow cell to
remove all traces of nitric acid. Monitor the pH of the outlet stream of the flow cell to
ensure that the acid has been completely flushed out.
For instructions on reinstalling the flow cell, see “Installing the LightPipe Flow Cell” on
page 14 .
CAUTION Do not use a syringe to force acid solutions through the flow cell.
Pressurizing the flow cell could cause a leak or rupture, resulting in a dangerous and
uncontrolled spraying of acid.
CAUTION
Before you pump nitric acid solution through the LightPipe flow cell,
ensure that the column has been removed from the chromatographic system and that
water was the last solvent in the pump and solvent reservoir.