Potassium tetraoxalate dihydrate [pH (S) = 1,67₉ (25 °C)] is a certified secondary standard reference material used as a calibration buffer standard for pH instruments or pH electrodes.

• The product is delivered with a comprehensive, batch-specific certificate of analysis showing the relevant data for the quality management system
• This buffer standard has a guaranteed shelf life of four years
• Intended for extremely precise calibration, qualification and monitoring of pH instruments and routine assessment of their performance

The pH value of this Certipur® buffer solution is qualified using differential potentiometry with two platinum hydrogen electrodes against NIST & PTB primary reference materials pH (S) = 1,679 (25 °C). Potassium tetraoxalate dihydrate buffer is a Certified Reference Material (CRM) offered in neat format. Solution of this standard is prepared in-house following instructions in European Pharmacopoeia (Ph. Eur. 2.2.3).