Merck, 1.09439.1000, Buffer solution

The buffer solution (di-sodium hydrogen phosphate/potassium dihydrogen phosphate) is gravimetrically prepared using high-quality salts in high-purity water. It is quality controlled and qualified in an ISO/IEC 17025 accredited calibration lab. Its pH value of 7.00 at 20°C is qualified following a 5-point calibration method, using a combined glass electrode, in accordance with DIN 19268, against reference buffer solutions following DIN 19266. 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.