To prepare a phosphate buffer, a specific ratio of NaH2PO4 and Na2HPO4 is mixed in distilled water. The exact proportions depend on the desired pH of the buffer. Here is a basic guideline for preparing 0.1 M phosphate buffer at pH 7.4:
1. Dissolve 20.21 g of Na2HPO4 in 1 liter of distilled water. 2. Dissolve 15.60 g of NaH2PO4 in 1 liter of distilled water. 3. Mix the two solutions in the appropriate ratio to achieve the desired pH. 4. Verify the pH using a pH meter and adjust if necessary using small amounts of NaH2PO4 or Na2HPO4.
