Ionode IJ pH V5.1 - Manual (Page 23)

Ionode IJ Instruction Manual 23
4.5.2. Secondary pH Buffers
pH 7.65: Tris Buffer
Dry Tris (2-amino-2-(hydroxymethyl)propane-
1,3-diol) and Tris hydrochloride at 80
o
C and
40
o
C, respectively. Dissolve 1.999g of Tris and
7.800g of Tris hydrochloride in water and make
up to 1L. Alternatively, prepare the solution by
dissolving 8.008 g of Tris in 50mL of 1M HCl
and make up to 1L with deionised water.
pH 7.00 @ 25
o
C: Phosphate Buffer
Prepare 500mL of 0.1M KH
2
PO
4
from the dried
salt. Accurately prepare 500mL of 0.1M NaOH.
Mix 500mL of the KH
2
PO
4
solution with
296.3mL of the NaOH solution in a 1L
volumetric flask and fill to the mark with
deionised water.