Thermo Fisher Scientific CyberScan PD 300 - Manual (Page 56)

Instruction Manual PD 300
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 the
electrode in a pH 4 buffer solution for 10 to 30 minutes. If this fails, the electrode requires
activation. Never touch or rub glass bulb. Contact builds up an electro-static charge.
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. If possible, replace with another electrode instead of performing this re-activation
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 H
2
SO
4
) 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 the electrode yields
acceptable results. You may repeat step 3 through 6 up to three times for better
response. If the response does not improve, then your electrode is no longer functioning.
Replace with a new electrode – call your distributor for information.
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