Hello
Sometimes a method called "shocking" is used to revive pH electrodes. To shock your pH Sensor, perform the following:
1) Let the pH Electrode soak for 4-8 hours in an HCl solution between 0.1 and 1.0 M.
2) While the probe is soaking, prepare a batch of new storage solution. The recipe is: 10 grams of solid KCl dissolved in 100 mL of pH 4 buffer. Any pH 4 buffer mixture works well, but use only KCl for the salt - other salts do not work. (NOTE: Use this solution to store your pH probe when it is not in use.)
3) After the HCl soak, rinse off the probe and place it in 50-75 mL of the storage solution you made in step C. Soak the probe tip in this storage solution for 1-3 hours.
3) Rinse the electrode and give it another try.
We have found that many old electrodes can be revived in this manner. Generally, storing them in a storage solution (buffer pH 4 + KCl) will keep them in good condition.
Good Luck
Hello
Sometimes a method called "shocking" is used to revive pH electrodes. To shock your pH Sensor, perform the following:
1) Let the pH Electrode soak for 4-8 hours in an HCl solution between 0.1 and 1.0 M.
2) While the probe is soaking, prepare a batch of new storage solution. The recipe is: 10 grams of solid KCl dissolved in 100 mL of pH 4 buffer. Any pH 4 buffer mixture works well, but use only KCl for the salt - other salts do not work. (NOTE: Use this solution to store your pH probe when it is not in use.)
3) After the HCl soak, rinse off the probe and place it in 50-75 mL of the storage solution you made in step C. Soak the probe tip in this storage solution for 1-3 hours.
3) Rinse the electrode and give it another try.
We have found that many old electrodes can be revived in this manner. Generally, storing them in a storage solution (buffer pH 4 + KCl) will keep them in good condition.
Good Luck
Hi, Ebrahem,
In general I agree with Saleh.
If operation recommended by him will be not effective, try also:
1. Completely exchange an electrolyte solution inside of electrode. just soak by syringe old electrolyte and repalce it to fresh-made 3M solution of KCl.
2. Try to rocking electrode - put it to 1 M NaOH, wash in water, put to 1 M HCl, wash.
3. Do not forget re-calibrate electrode after your treatment. Use a buffer solutions near your working pH (4 and 7, or 7 nd 9). Slope must be in range 97-99%.
All the best,
Dear Mr Elkhtab, if the suggestion of the Prof. Alkarim does not work, you can try:
Leave the glass bulb immersed in sulfochromic solution 4-12 hs, you can leave more time. This procedure can recovery the response of the electrode to pH. If glass electrode is used with aqueous solutions containing organic matter or proteins, these adsorb under glass. Sulfochromic destroy this layer, regenerating the electrode. Another possibility is to use hydrofluoric acid (Leave just some seconds, better is to immerse and to wash immediately). This attack the glass leaving a new layer of sensitive glass to pH, but is better used when the problem is due to inorganic contaminants. Some manufacturers recommended to use pepsin (remove organic contaminants) or ammonium fluoride or thiourea (remove inorganic contaminants). Afterwards, wash the glass bulb and leave immersed for some days in 3M KCl.
It is also important to verify if the liquid connection (ceramic or sintered glass) between inner and external solution is blocked, because this can affect the potential. I hope these suggestions can help you. Good lucky.
Thank you all for your valuable information.
hope to you all the best
Hello Peer, this helps for cleaning residues of materials on the electrode, so that this helps in the activation.
what does it mean if during our calibration,our probe could only read 7.? wth buffer 4,it also read 7. and finally wth buffer 10, the same thing happened. it still read it as 7. could anyone please explain to me why could this happen? should i do the shocking method, and all suggested methods here?
Shahidah Arina Shamsuddin - probably cracked glass bulb, so the electrode is shorted. You can try to measure the impedance of the probe (when in storage buffer) - it should read high megaohms; if lower, there is short or a crack.
Dear Shahidah Arina Shamsuddin ,
since we do not know about the electrode model as well as the design of your pH-meter you are working with it would be only "wildcatting" about the real cause of the failure to measure proper pH-values despite using different adjusting buffers.... Zdenek Svindrych has mentioned a possibility.
Regarding the correct use and handling and storage of pH-meter-electrodes I found a short note in a SIGMA-(newsletter) leaflet I received in 2007: enclosed here only for your kind information... Best wishes and good luck!
Dear Zdenek Svindrych and Wolfgang H. Muss ,
thank u so much for ur reply.. u guys are so cooperative and helpful. very appreciate it.. thanks again..
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