- Density: ~ 1,00 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: 10,00rspecification range: 9,98 - 10,02runcertainty : ± 0,01rComposition per litre is 2,4g Sodium carbonate and 2,1 g Sodium hydrogen carbonate rrStandard buffer solutions are prepared using gravimetric and volumetric procedures. The batch value is determined by measurement with a combination glass electrode against two-point calibration according to DIN 19268. This pH buffer solution is traceable to Standard Reference Material from NIST. r0: 10,25r5: 10,18r10: 10,12r15: 10,06r20: 10,00r25: 9,97r30: 9,93r35: 9,91r40: 9,89r45: 9,83r50: 9,78r