Appendix (Electrodes And Electrode Care) - palintest MICRO 500 Operating Instructions Manual

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ELECTRODES and ELECTRODE CARE
CARE OF PALINTEST pH ELECTRODES AND ORP ELECTRODES
Palintest Electrodes are supplied with Palintest pH Meters and as
replacement items. Palintest Electrodes are also suitable for use with
other types of general purpose pH meters.
Modern combination pH electrodes are of precision construction and
comprise a glass electrode and reference electrode in a single unit.
The porous 'liquid junction' provides continuity between the electrode
and the test solution. Palintest Electrodes are normally of a sealed
liquid or gel type which do not require refilling.
The operation of the pH meter is entirely dependent on the status of
the pH electrode. For this reason it is important that the electrode is
properly looked after and carefully maintained. Attention to electrode
maintenance will ensure correct pH readings and long electrode life.
If the electrode is neglected increasingly inaccurate readings will be
obtained and a new electrode will soon be required.
pH electrodes, by their very nature, have a limited life span. It is
difficult to predict how often a pH electrode will need to be replaced
as this will depend on the nature and frequency of its use and on how
well it is maintained. Under normal conditions when testing water or
simple aqueous solutions, a typical electrode life of 6 - 12 months can
be expected. Where the electrode is being used with aggressive
solutions such as acids and alkalis, solutions containing particulate
matter or with solutions containing non-aqueous solvents, then a
shorter electrode life can be expected.
ORP Electrodes (oxidation-reduction potential or redox electrodes)
comprise a platinum electrode in combination with a reference cell.
Whilst the operation of ORP electrodes is somewhat different from pH
electrodes they require similar care and maintenance. These instructions
can therefore be applied generally for the maintenance of ORP
electrodes.
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