For 100ml of 50mM Sodium Phosphate Buffer (pH=7), I first prepared 100ml of 50mM of sodium phosphate monobasic anhydrous (NaH2PO4) and 50mM of sodium phosphate dibasic anhydrous (Na2HPO4) separately. And I added 39 parts of NaH2PO4 and 61 parts of Na2HPO4.
Could I do the same for the preparation of 100ml of 100mM Potassium Phosphate Buffer (pH=7). Could someone suggest me how to calculate for this mentioned buffer preparation?
The basics behind this goes, I suspect for many of us, a long way back in time.
But in essence it is based on:
Use (for example) the Henderson-Hasselbach equation to calculate how much acid and base you need: pH = pKa + log ([Base]/[Acid])
In other words: the pKa is already close to your desired pH 7.0 and the ratio (in molarities) determines the final pH of your buffer.
In more practical terms I suppose this link might help you:
https://www.aatbio.com/resources/buffer-preparations-and-recipes/phosphate-buffer-ph-5-8-to-7-4
The method is the same, but the proportions are slightly different between sodium and potassium phosphates.
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