What to do if...
Lab 865
56
ba77145e02
12/2017
No stable measured
value
Obviously incorrect
measured values
Cause
Remedy
pH electrode:
– Junction contaminated
– Clean junction
– Membrane contaminated
– Clean membrane
Test sample:
– pH value not stable
– Measure with air excluded if
necessary
– Temperature not stable
– Temper if necessary
Ele test sample:
– Conductivity too low
– Use suitable electrode
– Temperature too high
– Use suitable electrode
– Organic liquids
– Use suitable electrode
Cause
Remedy
pH electrode:
– pH electrode unsuitable
– Use suitable electrode
– Temperature difference between
buffer and test sample too great
– Adjust temperature of buffer or
sample solutions
– Measurement procedure not suit-
able
– Follow special procedure
