Certified Secondary Reference Buffer Solutions and Substances

Within its Certipur® range of certified reference materials for pH measurement, Merck provides certified secondary standard buffer solutions and buffer substances with exact reference pH values for extremely precise calibration, qualification and monitoring of your pH instruments and for testing other buffer solutions.

We measure and qualify our certified secondary pH reference materials in our own ISO/IEC 17025 accredited laboratory using differential potentiometry with two platinum hydrogen electrodes. This method allows the comparison of the certified secondary reference buffers to the corresponding primary reference materials by PTB Physical Technical Institute, Germany) and NIST (National Institute of Standards and Technology, USA). The uncertainty of those buffer solutions and substances is +/- 0.003 pH units. Uncertainty data and traceability are documented in a comprehensive, batch-specific Certificate of Analysis.