Why are 4 pH and 7 pH buffers recommended over a 10 pH buffer for calibration?

Document ID

Document ID TE2057

Version

Version 5.0

Status

Status Published

Published Date

Published Date 05/23/2018
Question
Why are 4 pH and 7 pH buffers recommended over a 10 pH buffer for calibration?
Summary
pH sensor calibration
Answer
A 10 pH buffer solution is unstable because it absorbs carbon dioxide (CO2) from the air. When CO2 is absorbed in water, it forms carbonic acid, which lowers the pH of the buffer. To prevent potential problems from calibrating with inaccurate pH 10 buffer solutions, we recommend calibrating with 4 pH and 7 pH buffers. This establishes a slope value which carries over to the high pH side. A 10 pH buffer can be used but we recommend using fresh 10 pH buffer whenever possible.

Was this answer helpful?

Submitting...
Thank you for your feedback!
There was an error with your submission. Please try again.