User Guide

Instruction Manual pH 510/ Ion 510
22
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.