Electrodes Holders; Ph Electrode Cleaning And Maintenance; Reconditioning - Etatron PB Serie Manual Del Usuario

PB-RX
12.0 - ELECTRODE HOLDERS
Three different types of electrode holders are available: monotubular for immersion, electrode cell, and in-line.
It is essential to bear in mind that the distance between the injection point and the electrode must never be less
than one metre. When this is not possible, an appropriate chemical mixer must be inserted between the injec-
tion point and the electrode.

13.0 - pH ELECTRODE CLEANING AND MAINTENANCE

When the electrode is not used for a lengthy period of time, it is important to preserve it immersed in a 3M potas-
sium chloride (KCl) solution. The formation of deposits on the electrode will produce erroneous readings. The
necessary cleaning action depends on the type of deposit under consideration. In the case of thin deposits, shake
the electrode in the manner of a thermometer or use a spray of distilled water. Organic residues or particularly
resistant deposits should be removed by chemical means. Mechanical cleaning of the bulb should be resorted to
only in extreme cases, but bear in mind that abrasion can lead to irreparable damage. If cleaning does not fully
re-establish the efficacy of the electrode, it may be that the electrode has aged. Ageing will show itself in the for
of either a measurement error or a slow response. Ageing can be ascertained by thoroughly cleaning the elec-
trode and then measuring a solution of known pH: if the error exceeds 10% (ten percent), reconditioning will
have to be resorted to. If even this fails to re-establish correct electrode performance, there is no alternative to
replacement.

13.1 - RECONDITIONING

Immerse the tip of the electrode in 0.1 N hydrochloric acid (HCl) for 15 sec., then rinse with water and reimmerse
the electrode in a 0.1 N solution of sodium hydroxide (NaOH) for 15 sec., followed by a second rinsing. Repeat
this sequence three times and then carry out another check measurement.
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