pH Buffer Calibration Verification

Work involving pH Buffer Calibration requires calibration standards that are dependable and accurate. Providing your equipment is maintained well, measuring pH should not be a chore. Be sure you routinely go through the meter checkout procedure for your meter (according to your manufacturer’s directions) and perform a check on your electrode.

Electrode checks involve submerging the electrode in pH buffers 4 and 7 and taking millivolt readings, then subtracting the difference and checking that that figure falls within their parameters. Failure of checking the electrode will result in erratic reading and drift.

Three point calibrations give the most accurate results. For less demanding work, 2 point calibration is useful and quicker. Exaxol did some internal testing and found that of 3 brands obtained, not one was within the 0.1 pH unit tolerance guaranteed by the manufacturer, and total variation between the 3 was a staggering 0.5 units.

NIST Traceable means that the manufacturer is using these materials provided by NIST, drying the appropriate ones (some should not be dried), weighing them on a semi micro balance, and dissolving the salts in high purity carbonate-free water to volume. These prepared standards are then used to calibrate the meter before measuring/testing the values of the buffers manufactured in house. This procedure is then repeated for ultimate accuracy.

Exaxol performs these steps in preparing high quality standards for pH measurement. Our pH buffers can be found here, for your convenience.