Thermo Fisher Scientific CyberScan pH/Ion 510 - Manual (Page 27)

Instruction Manual pH 510/ Ion 510
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6.4 pH Electrode Rejuvenation
CAUTION: Proper protective eyewear and precautionary measures must be used when performing the rejuvenation
procedure as it involves the use of concentrated acid and alkaline.
Generally, if procedure of storage and maintenance had been closely followed, the pH electrode can be used
immediately. However, should the electrode response become sluggish, it may be possible that the glass bulb has
dehydrated. Immersing the electrode in an ideal storage solution (e.g. buffer pH 4 solution) for 1- 2 hours can dehydrate
the glass bulb. If this fails, the electrode may require re-activation. At no time should you touch or rub the glass bulb as
this causes the build-up of electrostatic charge. If the above procedure does not re-activate electrode to acceptable
status, try rejuvenating electrode by following the procedure outlined below.
6.4.1 Rejuvenation Procedure
1. Dip and stir the electrode in freon or alcohol for 5 minutes.
2. Leave the electrode in tap water for 15 minutes.
3. Dip and stir the electrode in concentrated acid (e.g. HCl, H
2
SO
4
) for 5 minutes.
4. Repeat Step 2.
5. Dip and stir in strong base (NaOH) for 5 min. Leave for 15 minutes in tap water.
6. Test with standard calibration buffer solutions.
Finally, test with standard calibration buffer solutions to see if the electrode yields acceptable results. You may repeat
steps 3-6 again for better response (maximum 3 times). If the response does not improve, then the electrode has
completed its useful life. Replace with a new electrode.