Just for the record (what with everyone concerned about 'dangerous'
chemicals) this compound is used industrially as an antioxidant in soaps,
edible fats, oils, and other stuff we humans use! It would be interesting
to experiment (I don't have the time just now) to determine if other, less
exotic, antioxidants would work in this application. I also don't know why
it has to be the disodium salt, as the compound is freely soluble in water;
it may be that it is has a low pH (I have no data on this) so the compound
could be neutralized with any alkali while making up the solution. Don't
know - good area for experimentation. And, John, if you've got so much of
this harmless substance, why not make small amounts available to serious
experimenters?
Sil Horwitz, FPSA
Technical Editor, PSA Journal
silh@iag.net
Visit http://www.psa-photo.org/