[mithunsugun]

i m a research scholar. i came across an enzyme assay, and in which its needed to make a citrate phosphate buffer wit pH 6.5. could anybody give me some suggest the composition of the same. it wil b grateful...
thank u....

[Rabn]

I suggest Henderson-Hasselbalch.

[Borek]

Henderson-Hasselbalch equation won't be easy to use - this is a mixture of triprotic acid (citric) and triprotic base (phosphate) and at pH 6.5 we have to take into account both third dissociation step of a citric acid and second step of the phosphate hydrolysis. Calculations will be complicated.

For all practical purposes it is much easier and much better to use my Buffer Maker here than to calculate such  buffer by hand.