Thermo Fisher Scientific Alpha pH 500 - Manual (Page 25)

21
Reactivating the pH electrode
If stored and cleaned properly, your pH electrode should be ready for immediate
use. However, a dehydrated bulb may cause sluggish response. To rehydrate the
bulb, immerse electrode in a pH 4 buffer solution for 10 to 30 minutes. If this fails,
the electrode requires activation.
pH electrode activation (for glass body electrodes only)
WARNING: Only qualified persons proficient with the safe handling of dangerous
chemicals should perform the procedure below. Provide proper containers, fume
hoods, ventilation, and waste disposal. Safety goggles and protective clothing must
be worn while performing this procedure.
1. Dip or stir the pH electrode in alcohol for 5 minutes.
2. Leave the electrode in tap water for 15 minutes.
3. Dip and stir the electrode in concentrate acid (such as HCL or H2SO4) for
five minutes.
4. Repeat Step 2.
5. Dip and stir in strong base (NaOH) for five minutes.
6. Leave for 15 minutes in tap water.
7. Now test with standard calibration buffer solutions to see if electrode yields
acceptable results. You may repeat step 3 through 6 up to three times for
better response. If response does not improve, then your electrode is no
longer functioning. Replace with new electrode – call your distributor for
information.