buffer pH unsteady - (May/08/2006 )

Hello,

I'm new here and also just started my diploma work some weeks agao.

I'm using an 10mM Ammoniumacetate 0,1% TritonX buffer. The problem is that this buffer is unsteady (within one week the pH is shaking between 6,5 and 7,45).

details:

1L of buffer stored in a 1L bottle at room temperature


does anyone know how to get rid of the fluctuating pH? I just want it at pH 7,0.


thanks alot

regards

marek

Marek,

check the buffer capacity. You may have the pH right, i.e. the ratio of acid and salt is correct but there just isn't that much of it. It may be degrading. Try keeping the bottle in the fridge.
If all else fails, make up fresh but in smaller volumes.

I would say that ammonium acetate is not suitable to buffer around 7.0
It's used for something pH around 4-5, am I wrong?

hi
it seems that missele is right. Ammoniu seems nto the optimal for this temperature.
I think also that 10mM ammonuim is a working concentration, and you may prepare a 10x pr 100x solution which probably better keeps the pH.

thanks alot @all !!

I will keep your advice in mind !!!

regards
marek