Conductivity meter electrodes normally become
coated with impurities. The degree to which this occurs will depend upon
the nature of the samples being tested.
will also depend upon whether or not the electrode is rinsed with
distilled water and properly stored after each use (Fig 11.4 & 11.5).
contamination causes a
decrease in the effective surface area of the electrode exposed to the
solution. This will lead to lower values being recorded, unless frequent
calibration is performed. When correct practices are followed, quality
conductivity equipment needs calibrating only a few times per year. An
indicator of the need to clean is given by the extent to which the meter
drifts out of calibration.
Storing conductivity electrodes
Store the electrode in distilled water when
it is not in use (Fig 11.5). If contaminants are not removed by the
rinsing process, they will tend to encrust on the electrode’s surface if
left to dry out.