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11.2.3 Replatinising Salinity/TDS Electrodes
There are several ways to replatinise Salinity/TDS electrodes.
1. The simplest way is to return the electrode to the TPS factory. We can fully
clean the electrode, replatinise it and test all aspects of its performance.
2. An automatic replatiniser is available from TPS, along with replatinising
solution. This will plate the electrodes for the right amount of time at the
correct current. Ordering details are as follows:
Automatic Salinity/TDS Electrode Replatiniser Part No 122160
20mL Platinising Solution (suitable for approx 30 uses) Part No 122300
3. Salinity/TDS electrodes can be manually replatinised, according to the
following procedure:
1) Soak the electrode in a solution of 1 part Concentrated HCl and 10 parts
distilled water for approximately 5 minutes.
2) Rinse the electrode well in distilled water.
3) Immerse the electrode in platinising solution to the same level as for
calibration (see section 4.1). Platinising solution is available from TPS (part
no 122300). Alternatively, platinising solution can be prepared by
dissolving 1g of Hydrogen Chloroplatinate (H
2
PtCl
16
) in 30mL of distilled
water, and including about 0.01g of Lead Acetate ((CH
3
COO)
2
Pb) and a
drop or two of concentrated HCl.
4) Apply a direct current of 10mA between red and black wires of the
electrode cable, as per the diagram below. Reverse the polarity every 30
seconds. After approximately 8 minutes (4 minutes per electrode wire), they
should have an even “soot” like appearance. Avoid excess current and this
will cause incorrect platinising.
5) After platinising, rinse the electrode well in distilled water.
6) If you have any doubts about any of these steps, then you should consider
returning the electrode to the factory. The cost of replatinising is quite low,
and you will be guaranteed of the best possible result.
