[coquim]

Sodium phosphate 50mM but to ph=2,5
i couldn´t find anyting in books and on the net.
Could anyone please help me with this?
Is it possible to adjust the ph with phosphoric acid?
Thanks!!!!!!

[Borek]

Is it possible to adjust the ph with phosphoric acid?

Exactly - and that's what you are supposed to do.

[Arkcon]

That's one way of doing it, 'tho some people don't care for that method much.  You can also prepare it from the correct mixture of sodium phosphate monobasic and dibasic.  I think there may be some source for a buffer prep program, I just can't recall where ... if only someone could provide a buddy for making buffers ...

[agrobert]

http://www.columbia.edu/~scb2001/tools/phosphate/phosphate.html

[Borek]

You can also prepare it from the correct mixture of sodium phosphate monobasic and dibasic.

Better think it over... pH 2.5 is too low for that.

I think there may be some source for a buffer prep program, I just can't recall where ... if only someone could provide a buddy for making buffers ...

Buddy... could be ChemBuddy?

Wanna be a betatester? Release date not yet set, hopefully about a month or two from now. Betatests will start earlier.

Note: there are several programs that pretend to be able to calculate buffer. Those that I have seen are based on misunderstood Henderson-Hasselbalch equation, so they will tell you how to prepare 0.01M pH 2.33 buffer from chloroacetic acid - when pure chloroacetic acid of this concentration has pH around 2.5. They will also not calculate how to prepare citrate/phosphate buffer, as it is not described by HH.