Oyster10-en-US_v2.3 9/15
9
Troubleshooting an Electrode Problem
Symptom
Cause
Recommended Solution
Long response time or
reading drift
Clogged Junction
Soak in 4.07 M Potassium Chloride (KCl)
@ 60
o
C for 30 minutes. Replace
electrode if necessary.
Strong Alkaline measurement Soak in 0.1 M HCL overnight
Deteriorated Gel layer of pH
sensing membrane
Replace electrode
Protein coating on electrode
surface
Soak in 1 gm Pepsin dissolved in 100ml
of 0.1 m HCL for 30 mins. or as needed
Oil, paint, dyes, suspended
solids on sensor
Rinse electrode alternately with materials
solvent (briefly) then a buffer 7.00
Organic solvents are coating
sensor
Organic mole fraction has to be less than
50% to assure reasonable readings. Limit
time of measurement. Keep probe in the
7.0 buffer between readings.
Dehydrated membrane
Read solution for dry bulb below
Dry Bulb
Long term storage without
wetting
Soak electrode tip in wetting cap filled
with 1ml 7.00 buffer for 24 to 48 hours
Static Charge
Wiping electrodes
Rinse electrode in 7.0 buffer and blot. Do
no wipe electrode.
Same readings in
different buffers and
samples
Cracked or broken bulb
Replace electrode. Use bulb guard. Avoid
plunging electrode to bottom of container
and spinning bars. A wetting cap will
protect bulb between measurements.
Erratic LCD display
Samples have low ionic
strength (lacks salt); e.g.
distilled, de-ionized, boiled,
lake water (high pressure)
For each 50 ml of sample add 1 drop
(50uL) of SAT.KCL No alteration in pH
will occur by inert KCL.