Accurate pH test

by Roger

In order to maintain a reasonable degree of accuracy when making a pH measurement, proper handling, storage, and use of buffers is important. If the buffers are contaminated or used improperly, the calibration will be in error and all subsequent measurements will be wrong.


• Do not use buffers after their expiration date. Store buffers at controlled room temperature.

• Protect buffers from excessive exposure to air. Always cap the buffer container when storing.

• Before starting calibration, be sure the sensor and the buffer are at the same temperature. If possible, calibrate with buffers having the same temperature as the process.

• Do not return used buffer to the stock bottle. Discard it.

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Nov 28, 2015
Temperature of buffer?
by: Sarah

Very useful info. A query though: the buffer solutions provided with my ATC PH meter state use @ 25 degrees. However, elsewhere it is stated that the buffer and the medium to be tested should be near the same temperature. As I am testing pondwater which is never anywhere near 25 degrees, would I still have accuracy having used a buffer at 25 degrees to calibrate? Any advice gratefully received.

May 29, 2010
Temperature dependent
by: David

Buffer values are dependent upon temperature. Make sure you use the right number. Check the supplied table that gives the pH value of your buffer at various temperatures.

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Download the new release ISO 14001:2015