SRM2181 - SRM2184
These materials are intended for use in preparing a standard solution for calibrating clinical instruments (e.g.
blood pH measurements), in the physiologically important range of pH 7-8. They are based on a biological
buffer system for clinical pH measurements and are certified for use as an admixture only. The pH values for
the buffer solutions are certified at 0.05 and 0.08 M with respect to the free acid and the sodium salt
admixture as a function of temperature. The certified temperature range is from 0-50 ℃.

HEPES Sodium Salt-Biological buffer systems
Certified values
0.05M
pH (0-50 ℃)............ 7.832-7.216
0.08M
pH (0-50 ℃)............ 7.853-7.222