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Buffer solutions

traceable to NIST, traceable to PTB, pH 4.01 (25 °C, phthalate), pH 7.00 (25 °C, phosphate), pH 9.00(borate), Certipur®


certified reference material

Quality Level


traceable to NIST
traceable to PTB

product line



4.01 (25 °C, phthalate)
7.00 (25 °C, phosphate)


food and beverages
general analytical
industrial qc



storage temp.


General description

It includes a pack of three certified buffer solutions, gravimetrically prepared using high-quality reagents and water at a registered calibration laboratory. Their pH values of 4.01 (phthalate), 7.00 (phosphate), and 9.00 (borate) at 25°C are measured using combined glass electrode as per the 5-point calibration method. The measurements are made following DIN 19268 using reference buffer solutions compliant to DIN 19266, NIST, IUPAC, Ph. Eur, and USP. The pH of buffers is strongly dependent on the temperature and therefore a constant temperature must be maintained during their use.


They are used as standards to calibrate pH measuring instruments or pH electrodes and as controls to measure the pH of other solutions.

Features and Benefits

  • Measured and qualified at an ISO/IEC 17025 and ISO 17034 accredited laboratory
  • Traceable to secondary reference standards from NIST and primary certified reference standards from PTB
  • Ready-to-use solutions available in 30 mL sachets
  • Accompanied with a detailed and batch-specific certificate of analysis (CoA) for an effective audit
  • Product label follows the ISO Guide 31 and contains information about ordering number, article description, lot number, safety data, and expiry date
  • Packaging material subjected to comprehensive stability studies as per ISO Guide 35
  • pH 4.00 and pH 6.99 buffer CRMs in the pack are accurate upto +/- 0.02 at 25 °C and the pH 9.00 buffer CRM is accurate upto +/-0.03 at 25 °C

Legal Information

CERTIPUR is a registered trademark of Merck KGaA, Darmstadt, Germany

Storage Class Code

10-13 - German Storage Class 10 to 13

Certificate of Analysis

Enter Lot Number to search for Certificate of Analysis (COA).

Certificate of Quality

Enter Lot Number to search for Certificate of Quality (COQ).

Our team of scientists has experience in all areas of research including Life Science, Material Science, Chemical Synthesis, Chromatography, Analytical and many others.

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