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5. Maintenance
5.1 Cell Cleaning and Storage
The single most important requirement for accurate and reproducible results in conductivity
measurement is a clean cell. A dirty cell will change the conductivity of a solution by
contaminating it.
To clean a conductivity cell:
1.
Dip or fill the cell with cleaning solution and agitate for two to three minutes. Any one of
the foaming acid tile cleaners, such as Dow Chemical Bathroom Cleaner, will clean the
cell adequately. When a stronger cleaning preparation is required, use a solution of 1:1
isopropyl alcohol and 10N HCl or Sulfuric Acid or Ethanol or Methanol.
CAUTION: Cells should not be cleaned in aqua regia or in any solution known to etch
platinum or gold.
2.
Remove the cell from the solution and rinse in several changes of distilled or deionized
water. Inspect the platinum black to see if replatinizing is required.
Storage
Short term: Store conductivity cells in deionized or distilled water. Change the water frequently
to prevent any growth that may cause electrode fouling.
Long term: Rinse thoroughly with deionized or distilled water and store dry. Any cell that has
been stored dry should be soaked in distilled water until the electrodes appear black
before use.
5.2 Platinization
The electrodes of YSI 3200 and 3400 Series conductivity cells are coated with platinum black
during manufacturing. This coating is extremely important to cell operation, especially in
solutions of high conductivity.
The cell should be inspected periodically. If the coating appears to be thin or if it is flaking off,
the electrodes should be cleaned, as noted above, and replatinized. Properly maintained
conductivity cells will perform for years without replatinizing.
The 3100 can be used to replatinize the electrodes of the cell. In addition, you will need a 2-oz
bottle of platinizing solution (YSI 3140).
WARNING: Before replatinizing the electrodes of a cell, make sure that the cell is
designed to have a platinum coating on the electrodes.
1.
Immerse the cell in the platinizing solution (YSI 3140). Make sure that both electrodes are
submerged.
