| | EGTA Stock Solution
On Thu, 11 Sep 2003, Richard P. Grant wrote:
It works. I worked in a lab that did this and used the stock to stop
Yes. I think some people used to heat it, too, if they were impatient.
While we're on the subject, this 'pH it to get it into solution' business
has always irritated me. We know the pKas of EGTA, right (or at least we
can look them up somewhere, although this data is often a pain to find)?
And we know how acids and bases work, right? So why can't we *calculate*
how much NaOH we need to add to get the right pH, then just mix the EGTA,
NaOH and water together, and let it all dissolve on its own (well, in the
company of a stirrer, anyway)?
I did this at one point with EDTA; 93.05g of Na2.EDTA (FW 372.2), 10.14g
of NaOH (FW 40), 500 ml dH2O, let it all dissolve, and it's bang on pH
8.0, at 500 mM EDTA.
If you don't trust this method, you can always go a bit short on the NaOH
and then pH it to your satisfaction otherwise; even if it's not perfect,
it'll save a lot of time.
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