- Density: ~ 1,005 g/cm3 r- Solub. in water: (20 ºC): miscibler- Tariff number: 3822 00 00 00r- Applications: This reference material is intended for the calibration of pH meters and electrodes used for pH measurement or as a control sample for measuring the pH value.rrSPECIFICATIONSrpH at 20 ºC: 7,00rspecification range: 6,99 - 7,01runcertainty : ± 0,01rComposition per litre is 3,5 g Potassium dihydrogen phosphate and 12,5 g di-Sodium hydrogen phosphate. Contains preservative. rrStandard buffer solutions are prepared using gravimetric and volumetric procedures. The batch value is determined by measurement with a combination glass electrode against five-point calibration according to DIN 19268. This pH buffer solution is traceable to Standard Reference Material from NIST. r0: 7,13r5: 7,07r10: 7,05r15: 7,02r20: 7,00r25: 6,98r30: 6,98r35: 6,96r40: 6,95r45: 6,95r50: 6,95r