Hi!
I am a graduate student in biological physics who prepares protein samples
using Sodium Hydrosulfite as a reducing agent (~100 mM concentration), and
I am wondering if there is an easy way to measure reducing agent "strength"
in order to determine if a day old reducing mixture is still good enough to
use for samples (stored in a gas tight vial with CO or N2 gas replacement)?
I am thinking that there must be something that chemists or biochemists might
use to measure this (like pH paper or indicators?).
Thanks for your help. (Please respond by email.)
Brad Banko
b-ba…@uiuc.edu
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Brad Banko; Dept of Physics; U of Illinois; b-ba…@uiuc.edu
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Tatiana Gutsu for President! 73 de kb8cne @ n9lnq.il
>>>>> On Fri, 18 Dec 1992 19:34:47 GMT, btbg1…@uxa.cso.uiuc.edu (Bradley T Banko) said:
Bradley> Hi!
Bradley> I am a graduate student in biological physics who prepares
Bradley> protein samples using Sodium Hydrosulfite as a reducing
Bradley> agent (~100 mM concentration), and I am wondering if there
Bradley> is an easy way to measure reducing agent "strength" in order
Bradley> to determine if a day old reducing mixture is still good
Bradley> enough to use for samples (stored in a gas tight vial with
Bradley> CO or N2 gas replacement)?
Bradley> I am thinking that there must be something that chemists or
Bradley> biochemists might use to measure this (like pH paper or
Bradley> indicators?).
you can always titrate with an oxidant. MnO4 perhaps?
assuming you know the stoichiometry of the reaction. This approach
would take more time than making fresh solutions, but you could do a
time course over a few days, then you will know that generally a
solution will be usable for N days….
Nathan Siemers
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From article <BzGzq2….@news.cso.uiuc.edu>, by btbg1…@uxa.cso.uiuc.edu (Bradley T Banko):
> I am a graduate student in biological physics who prepares protein samples
> using Sodium Hydrosulfite as a reducing agent (~100 mM concentration), and
> Brad Banko
> b-ba…@uiuc.edu
We are doing research on Sulfur-oxy anions, with our main
emphasis on sodium dithionite (or commonly:hydrosulfite).
What pH are you working at? Unless you are working
under very basic conditions (pH>11) your solutions
are not even good for 1 day, even under N2. At
neutral pH, your solution will have undergone *significant*
decomposition in as little as a couple hours!
E-mail me if you have further questions.
Bill (hodge…@csd4.csd.uwm.edu)
Iodine is a good mild oxidant for titrating reducing solutions to see if they
are up to strength (a bit of soluble starch can be used as an indicator).
Another approach would be to add an excess of a mild oxidant (perhaps
dipyridyl disulfide–that’s pretty mild) and back-titrate.
Steve
>>>>> On Mon, 21 Dec 1992 15:05:59 GMT, s…@chinet.chi.il.us (Stephen Jacobs) said:
Stephen> Iodine is a good mild oxidant for titrating reducing
Stephen> solutions to see if they are up to strength (a bit of
Stephen> soluble starch can be used as an indicator). Another
Stephen> approach would be to add an excess of a mild oxidant
Stephen> (perhaps dipyridyl disulfide–that’s pretty mild) and
ucky poo
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