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Can you rely on your buffer solution? Keywords such as GMP, GLP, ISO 9001, EN 45000, calibration, testing, traceability, and certification from authoritative certification bodies are becoming increasingly important. Calibrating pH and redox potentials is not an easy task. All calibration procedures assume that the labeled values of the calibration buffer are correct. However, the value of the buffer changes over time, and as a result, the measurement results also change. Patented pH buffers across the full range offer unprecedented pH stability. HAMILTON guarantees that the DURACALpH buffer has a shelf life of 5 years. Buffers at pH 9.21 and pH 10.01 are more stable in air, making calibration fast and reliable. High-performance buffers provide fast and stable calibration, while inhibiting the growth of fungi and microorganisms. Traceability runs through the entire closed chain; the important issue of producing certified references, by comparing them with references of the highest metrological quality (primary references) from NIST1) and PTB2), is aimed at ensuring traceability. Unlike other manufacturers, Hamilton does not use a top-down tracing method; instead, it employs a circular or closed-loop tracing approach. This closed-back tracing method ensures unparalleled reliability for users of Hamilton DURACAL buffers! Top-down tracking approach: In Hamilton, the pH value of DURACAL buffer was determined after comparison with two secondary buffers. These buffer solutions were purchased from suppliers that provide secondary references. These solutions are themselves compared with the primary buffers of PTB1) or NIST2). We are able to understand and record the measurement uncertainty from each comparison measurement. Bottom-up tracking approach: To ensure the highest accuracy and complete reliability of pH values, a representative sample size from each batch is sent to the DKD3 laboratory in Germany for third-party testing. In this laboratory, the DURACAL samples were compared with the secondary reference solution from DKD-K-06901. The secondary reference solution must of course also be compared with the primary reference solution from PTB. At this stage, the loop is closed: the PTB Grade 1 reference solution is the starting point and ending point of the traceability loop. DKD3) provides calibration certificates for each batch of DURACAL buffer from Hamilton. Due to the full traceability of the measurement procedures and the allocation of uncertainties in the specific testing steps, DURACAL buffer is classified as a “Certified Reference Material” (CRM – Certified Reference Material). Features • Convenient 250mL and 500mL plastic bottles with built-in calibration cups • Cost-effective – only 20 mL of buffer solution is required per calibration • Actual values determined by DKD laboratories specializing in pH measurement • Comes with a grade 1 certificate that complies with international standards for traceability • The certificate can be found at http://www.hamiltoncompany.com/cert • Expiration date printed on the bottle • Microorganism inhibition 1) NIST – National Institute of Standards and Technology, Gaithersburg, Maryland, USA 2) PTB – German Federal Institute for Physical Technology, Germany 3) DKD – German Calibration Service DKD-K-06901, Measurement and Calibration Center GmbH, Wolfern, Germany