Calibration of pH Meter Probe

Crimpshrine13

Involved In Discussions
We have a pH meter that needs to be calibrated every day before use, and my assumption is that it is okay to use the calibration buffer solution that is standardized using a pH meter calibrated by means of standard solutions prepared from NIST standard reference material as long as I have the certificate of analysis, or is my understanding incorrect?

If my understanding is correct, how does everyone keep track of the calibration record for pH meter that needs to be calibrated every day? Should I be writing down the pH meter value for each buffer tested and corresponding buffer lot numbers, then keep the record of certificate of analysis? What is considered acceptable for IATF? pH meter is something new we recently added due to our new process, and we do not have other equipment similar to this to compare.

If anyone can pitch in some ideas for maintaining pH meter calibration records it's much appreciated. Thank you.
 

Ron Rompen

Trusted Information Resource
I did something almost identical in a previous factory where we used pH meters. As you suggested, log the value of the buffer solution, lot number of the solution (this may be overkill, but it depends on the criticality of this measurement), the actual value reported by the meter, and of course the date tested and the initials/signature of the person performing the test. Also ensure that you have a documented reaction plan for when the meter and the buffer solution values don't match.
 

Crimpshrine13

Involved In Discussions
I did something almost identical in a previous factory where we used pH meters. As you suggested, log the value of the buffer solution, lot number of the solution (this may be overkill, but it depends on the criticality of this measurement), the actual value reported by the meter, and of course the date tested and the initials/signature of the person performing the test. Also ensure that you have a documented reaction plan for when the meter and the buffer solution values don't match.


Thanks. I will probably do the same. I just wanted to see what everyone else do since this was a new thing in our facility. We'll probably have to keep track of the lot numbers because our calibration must be traceable to national standard as our quality system is IATF 16949 and must follow ISO 17025 standard.
 

NorryTesi

Registered
Hi....the pH of exceptionally purged water isn't precisely estimated by test units, or by pH meters. There are a few distinct explanations behind this, including the way that exceptionally cleaned water has almost no buffering limit, so its pH is effortlessly changed. Indeed, even the sharpness or basicity of a pH test unit's marker color is sufficient to change unadulterated water's deliberate pH. With respect to pH meters, the tests themselves don't work well in the exceptionally low ionic strength of unadulterated freshwater, and follow pollutions on them can swing the pH around a considerable amount.
 
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