YSI ScienceLine -- pHT - G - Manual (Page 8)

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Aging, Maintenance and cleaning ScienceLine
Aging
Every pH combination electrode undergoes a natural aging process.
With aging, the responding behavior becomes slower and the electrode slope
and asymmetry change. Moreover, extreme operating conditions can
considerably shorten the lifetime of the combination electrode. These are:
• Strong acids or lyes, hydrofluoric acid, organic solvents, oils, fats, bro- mides,
sulfides, iodides, proteins
• High temperatures
• High changes in pH and temperatures
• The warranty does not cover failure caused by measuring conditions and
mechanical damage.
Refilling the
reference
electrolyte
Maintenance and cleaning
During operation, a small amount of reference electrolyte leaks through the
junction from the combination electrode into the test sample.
If the level of reference electrolyte becomes too low with time, refill it through
the refilling opening. Refilling is very easy with the enclosed dropping bottle.
Proceed as follows:
• Cut off the tip of the dropping bottle at a right angle until the opening in the tip
can be seen
• Open the refilling opening of the combination electrode
• Press the tip of the dropping bottle into the refilling opening while turning it
slightly
• Pump the reference electrolyte in the shaft using the dropping bottle
• Pull the dropping bottle out of the refilling opening while turning it slightly if
necessary