Buffer solution

Description

• General description: The citric acid/sodium hydroxide/hydrogen chloride buffer solution is gravimetrically prepared at a registered calibration laboratory with high-quality reagents and water. Its pH value of 4.00 at 25°C is measured using a combined glass electrode following a 5-point calibration method. The measurement is made following DIN 19268 using reference buffer solutions compliant to DIN 19266, NIST, IUPAC, Ph. Eur, and USP. The buffer pH is temperature dependent and therefore a constant temperature must be maintained during its use.Please visit ISO certificates and Site Quality Self-Assessments to access the current certificates of accreditation.Download your certificate at http://www.sigma-aldrich.com to view certified values, including uncertainty and expiry date.
• Application: The buffer is used as a standard to calibrate pH measuring instruments or pH electrodes and as a control to measure the pH of other solutions.
• Features and Benefits: Measured and qualified at an ISO/IEC 17025 and ISO 17034 accredited laboratoryTraceable to secondary reference standard from NIST and primary certified reference standard from PTB Available as a ready-to-use solution in 30 mL sachets Accompanied with a detailed and batch-specific certificate of analysis (CoA) for an effective auditProduct 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 35An uncertainty of +/- 0.02 in the pH value at 25°C
• Legal Information: CERTIPUR is a registered trademark of Merck KGaA, Darmstadt, Germany