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Maintaining and cleaning the flowcell
The high sensitivity of the detector and the low volume of the
flowcell make it imperative that a high standard of solvent purity
and general system cleanliness be maintained. A contaminated
flowcell can lead to noise and drift problems that are often
mistakenly attributed to other areas of the system.
The cell can be cleaned in place by using the following
procedure:
1. Remove all reservoirs containing organic solvent from the
system. Replace the column with a clean length of 1.6 mm
(1/16") OD stainless steel tubing. Fill all of the reservoirs with
HPLC grade water and flush the system thoroughly to
remove any trace of organic solvents.
2. After the system has been rinsed with water, pump 25%
phosphoric acid through the flowcell. This acid is prepared by
diluting one part of concentrated phosphoric acid with three
parts of HPLC grade water.
3. After pumping 50 mL of the 25% acid through the cell at
1–2 mL/min, rinse by pumping 100–200 mL of HPLC grade
water through the system. Do not allow the acid to remain in
the cell for more than one hour. Dispose of the acid in
accordance with approved waste disposal procedures.
4. Do a final rinse with acetonitrile or methanol.
The frequency of need for cell cleaning depends to a great extent
upon the cleanliness maintained during routine operation. In
severe cases of contamination, for instance if there is precipitate
in the cell, the cell must be replaced.
CAUTION
Do not dismantle the flowcell.
