Mahmoud,

Thank you for your quick response,

but we wondered on eventual purity demands for the stock.

We could indeed calculate from a 95% to a 20% f.c., but the question is would any polluents possibly interfere ?

I use Methanol from Caledon Laboratory Chemicals (Cat #6700-1) with a purity of 99.8%. The following is the the ingredient list for 1 L of 1x transfer buffer (we've been using it for many years in our lab):

100 mL of 10x transfer buffer

660 mL ddH20

10 mL 10% sds

230 ml methanol

*For 10x transfer buffer:

-30.2 g tris-base

-144 g glycine

-adjust volume to 1 L with ddh20

we use pure methanol, 20% as well!