Measuring pH in 95% DMSO solutions?
renevanwezel at hotmail.com
Thu Oct 31 12:46:30 EST 2002
jsp at bio.auc.dk wrote in message news:<20021030163433.3406.qmail at ww02.hostica.com>...
> Hi there,
> I'm trying to make a 95% DMSO, 4.5% H2O, 0.5% CH2ClCOOH solution at pH 5, by adjusting pH with HCl.
> Im using a standard pH-meter (Hamilton minitrode), but I can't seem to get stable readings due to the low water activity. If I clean the electrode and re-introduce it into the DMSO solution I get a completly different reading. Does anyone have a good suggestion how to accurately measure the pH?
Get your water fraction at pH5 and then mix with DMSO. You could try
diluting your solution 10 fold to see whether your pH is still around
5 and not fluctuating.
More information about the Methods