4
Maintenance
Note
Do not use organic solvents (such as acetone or
tetrahydrofuran) or acid (above 1 mol/L) or alkaline (above 0.1
mol/L) cleansing solutions. Using such chemicals may
damage the body of the electrode or cause a decline in
performance.
To maintain electrode performance, replace the internal
solution approximately every one or two months.
(Refer to " Preparation " (page 2).)
Dirt on the responsive glass membrane or liquid junction
by the test solution may cause a decline in electrode
response and sensitivity or measurement error. If the
electrode is very dirty and cannot be washed clean
using pure water, perform cleansing.
Cleansing of electrode
1. Open the internal solution filler port.
2. Immerse the responsive glass membrane and liquid
junction in cleansing agent for approximately one hour
until contamination is removed. The responsive glass
membrane can also be cleaned by wiping it with cotton
gauze containing cleansing agent.
3. Rinse the electrode with pure water completely.
4. Replace the internal solution.
(Refer to " Preparation " (page 2).)
Note
Be sure to perform calibration prior to measurement after
cleansing the electrode.
Tip
Applying pressure on the internal solution and exuding it from
liquid junction have an effect of stabilizing pH response.
Type of dirt
Cleansing agent
General
Diluted neutral cleansing agent
Oil
Alcohol, or diluted neutral cleansing agent
Inorganic substance
Electrode cleaner (model 220) or Hydrochloric
acid approximately 1 mol/L
Protein
Cleansing agent including protein-cutting
enzyme (model 250)
Liquid junction
Electrode cleaner (model 220)
Altered of glass,
Slow-response
Electrode cleaner (model 220)
Storage
1. Wash the electrode well with pure water to remove
sample completely and wipe it with filter paper.
2. Close the internal solution filler port.
3. Wash the inside of the protective cap with pure water,
then add enough pure water to soak the sponge.
4. Attach the protective cap.
Note
Do not dry the responsive glass membrane and liquid
junction. If they are dry, replace the internal solution and
immerse them in pure water for 24 hours or longer. After
these procedures, perform calibration. If calibration cannot
be performed correctly, replace the electrode.
Avoid storing the electrode in hot and humid locations.
Store the electrode indoors, out of direct sunlight.
For accurate measurement
For accurate measurement, refer to items below.
Stir the sample with stirrer in measurement (calibration).
Perform temperature compensation manually or
automatically.
(Refer to the instruction manual of pH meter.)
Temperature of standard solution and sample should be
the same.
Rinse the electrode with the sample before
measurement.
Immerse the responsive glass membrane and liquid
junction in the sample completely. Make sure that the
surface of the internal solution inside the electrode is
higher than the surface of the sample solution.
Perform calibration before measurement.
If measurement is performed everyday, perform
calibration once or more a day.
Protective cap
