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Buffer solution

di-sodium hydrogen phosphate/potassium dihydrogen phosphate, traceable to NIST, traceable to PTB, pH 6.88 (20 °C), Certipur®

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certified reference material

Quality Level


traceable to NIST
traceable to PTB

product line



di-sodium hydrogen phosphate/potassium dihydrogen phosphate


6.88 (20 °C)


food and beverages
general analytical
industrial qc



storage temp.


General description

Certipur® buffer solution [di-sodium hydrogen phosphate/potassium dihydrogen phosphate buffer; pH 6.88 (20 °C)] is intended for use as a calibration standard for pH instruments or pH electrodes or as a control sample for measuring the pH value.

The ready-to-use Certipur® buffer solutions are prepared gravimetrically in our ISO/IEC 17025 accredited calibration laboratory from high-purity salts, acids and bases diluted in high-purity water. All balances are regularly calibrated with analytical weight sets traceable to primary standard reference materials from NIST and PTB. The pH-value is measured to the highest precision using a combined glass electrode after 5-point calibration (according to DIN 19268) against reference buffer solutions (according to DIN 19266, IUPAC, NIST, Ph.Eur. and USP).
Please visit ISO certificates and Site Quality Self-Assessments to access the current certificates of accreditation.
Download your certificate at to view certified values, including uncertainty and expiry date.


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Features and Benefits

  • Compliant: Produced according to EP and USP guidelines
  • Secure: Tested in our ISO 17025 accredited calibration laboratory
  • Ready for audits: Detailed certificate of analysis for every product
  • Convenient: Simply open the pack for quick, accurate pH calibration

Legal Information

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

Storage Class

12 - Non Combustible Liquids




Not applicable


Not applicable

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