Add 5.8 mL of glacial acetic acid(l.05 g/mL) to 900 mL of distilled water. Adjust the pH to 5.0 by the addition of l M(4 g/100 mL) sodium hydroxide solution(approx. 30 mL is required). Add 0.74 g of calcium chloride dihydrate and dissolve Adjust the volume to l L and store the buffer at 4°C.
Stable for approx. 2 months at 4°C. The stability of this buffer can be increased by adding sodium azide(0.2 g of sodium azideIL buffer).
Stable for approx. 2 years at room temperature.