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Maintenance
A pH or redox measuring system requires maintenance with regular intervals.
Cleaning and buffer adjustment is a normal and necessary maintenance that should be
carried out regularly.
Intervals
The interval between buffer adjustments and cleaning depends widely on the working
conditions. Therefore, the easiest way to find the most appropriate cleaning interval is
by checking for drift or deviation and take notice of a potential maintenance interval.
For instance, start out by cleaning and buffer adjusting every week.
If measurements are unchanged or just slightly changed after buffer adjustment, the
cleaning interval can be changed to two weeks and after that, one month.
The intervals are equally reduced if the electrodes are coated, or very dirty, and the
measurements are significantly changed after cleaning and buffer adjustment.
There are no general guidelines to cleaning and adjustment, but in most cases, a
monthly adjustment is sufficient. Before beginning a buffer adjustment, the electrode
must be thoroughly cleaned:
1.
first in portable water
2.
then, if necessary, in a degreasing fluid, like, for example a 5-10% hydrochloric
acid solution
3.
then, before the electrode is put into the buffer solution, and again in between
every step of the buffer adjustment, rinse with water and dry with a dry cloth.
Redox electrodes
Like pH electrodes, Redox electrodes require cleaning but not buffer
adjustment. However, MJK does deliver redox buffers for calibration of electrode and
transmitter.
If the transmitter is deviating from the reference values when put into the buffer solution,
the electrode must be exchanged.
Cleaning of the electrode
Use clean drinking water for cleaning the electrode.
A 5-10% hydrochloric acid solution can be used for cleaning if the electrodes are greasy.
Protein coatings are removed with Pepsin cleaning fluid.
Maintenance /Intervals
pHix® Compact V3. NG (next generation)
EN 4.10 Version 2202
29
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