Storing PH probe

[bluewill]

Randy had mentioned in another recent thread not to store PH probe in RO/DI as salts will creep out
I have been doing this on my Handheld Hanna PH probe . whats the suggested solution for storage ?

 

[AdamNC]

Just regular tank water is fine.

 

[JimWelsh]

A 3M solution of KCl.

 

[taricha]

A 3M solution of KCl.

Interested. More details?
Is this just for preserving the probe, or keeping calibration, or both?
Hanna recommends the 7.01 buffer as the storage solution.
May just be anecdotal, but the calibration of my Hanna meter seemed hold better after I switched from tank water and random buffers to consistently using the 7.01 solution.

 

[Randy Holmes-Farley Verified Community Expert]

Interested. More details?
Is this just for preserving the probe, or keeping calibration, or both?
Hanna recommends the 7.01 buffer as the storage solution.
May just be anecdotal, but the calibration of my Hanna meter seemed hold better after I switched from tank water and random buffers to consistently using the 7.01 solution.

That solution is close to what is inside the probe, so there's no net loss or gain of salts into or out of the pH probe. Storage in other salty solutions is also usually OK since we are not usually focused on extreme accuracy and often break probes before they'd otherwise die.

https://www.coleparmer.com/tech-article/ph-electrode-care

Storage
Always keep your pH electrode moist. We recommend that you store your electrode in a solution of 4 M KCl. If 4 M KCl is not available, use a pH 4 or 7 buffer solution. DO NOT store electrode in distilled or deionized water—this will cause ions to leach out of the glass bulb and render your electrode useless.

After storage, you may notice white KCl crystals forming outside your electrode. This will not interfere with measurements. Simply rinse the electrode and blot dry before use.

 

[taricha]

Hanna recommends the 7.01 buffer as the storage solution.

I misread. This is wrong.
Hanna recommends
"...If storage solution is not available, then pH 4.01 or pH 7.01 buffer can be used."
The storage solution they do recommend for my probe is this one
and the FAQ section on the storage solution says....

Q: Is this storage solution KCL 3M, or may I use KCL 3M instead of this solution because I don't have any more ?

A: Hi Ann, Our storage solution is a KCl solution. If you’re out of storage solution, you may use 3M KCl or electrolyte solution. Best, Hanna Instruments

This one's informative too.

Q: Is it the same solution to refill the electrode?

A: Hi Heidy,
Electrode storage solution and refill solution are not the same. Typically, single junction pH electrodes use the HI7071 electrolyte solution (3.5M KCl + AgCl), while double junction pH electrodes use HI7082 electrolyte solution (3.5M KCl)....

And finally...

Q: Is it satisfactory to use ph 7.01 calibration solution instead of the storage solution?

A: Hi Warren, No - we do not suggest using buffer solutions for storing pH electrodes. Storage solution is really the best to keep you electrode hydrated and working properly. If necessary, a 50/50 mixture of electrolyte solution and buffer would be acceptable, (non-colored buffers are required to avoid staining the glass and junction). Best, Hanna Instruments