Merck, 1.99004.0001, Buffer solution

The boric acid/potassium chloride/sodium hydroxide certified buffer solution is gravimetrically prepared using high-quality reagents and water at a registered calibration laboratory. Its pH value of 10.00 at 25°C is measured using a combined glass electrode following the 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 pH of the buffer is strongly dependent on the temperature 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.