mahroo1356, on 10 September 2012 - 09:56 AM, said:
I want to prepare phosphate potassium buffer 0.1 M (pH=7.4) , consist of 0.5 mM EDTA. Supposed daily consumption is 80mL.
I have 1M K2HPO4 stock, 1M KH2PO4 and 0.5M EDTA stock. My questions are:
- Could i be able to prepare 200mL of above mentioned buffer and use for one week via following method?
0.2mL EDTA 0.5 M + 16mL K2HPO4 1M + 4mL KH2PO4 1M
then dilute to 200mL (with adjusted pH).
what i would do is prepare a 1M stock of kphos, pH 7.4, using the 1M mono and dibasic stocks then dilute an aliquot to 0.1M (adding edta) as needed.
2. The prepared buffer should be stored in refrigerator?
can be if you prefer to prepare a larger than immediately necessary volume. the nice thing about kphos, as opposed to naphos, is that it doesn't crystallize at refrigerator temperatures.