- Density: 1,00 g/cm3 r- Solub. in water: (20 ºC): miscibler- LD 50 (oral, rat): 2660 mg/kg (pure substance)r- 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: 9,26rspecification range: 9,25 - 9,27runcertainty : ± 0,01rComposition per litre is 3,8 g di-Sodium tetraborate decahydrate tetraborate decahydrate. 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: 9,43r5: 9,41r10: 9,35r15: 9,30r20: 9,26r25: 9,21r30: 9,16r35: 9,10r40: 9,09r45: 9,07r50: 9,03r