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  1. #21

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    Pat, I know about the oxidation chemistry of Vitamin C. I'm just saying that it's unlikely to happen to solid crystalline ascorbic acid unless there has been contamination by an oxidant or the sample is really old.

    Our body doesn't really 'separate' the two possible isomers of ascorbic acid. It just uses one and not the other. The isomer derived from dextrose (glucose) is cofactor for enzymes that are chiral (they have "handedness" and can distinguish between mirror-image molecules the same way our hand can distinguish right- and left-handed gloves).

    For direct photographic purposes the two isomers should be identical since the photographic process doesn't care about chirality. Gelatin is highly chiral, though, but I don't think that its specific interaction with Vitamin C would make a difference.

  2. #22

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    Quote Originally Posted by Zathras
    What about your phenidone solution? Could it be headed south?
    It's fresh and has not changed color, so that seems very unlikely.

  3. #23
    Lee L's Avatar
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    Nov 2004
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    I have both NOW Foods, which is Sodium Ascorbate, and Vitamin Shoppe, which is ascorbic acid. You might want to try Gainer's method for converting ascorbic acid to sodium ascorbate if that's what you have, and then check to see if it behaves like your NOW Foods did.

    Lee

  4. #24
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    I think there is another possibility. I saw a container of what was purported to be Vitamin C, but had on the label the formula of dehydroascorbic acid. Our bodies, at least in some circumstances, can use that. The body converts ascorbic acid to dehydroascorbic acid in order to pass the brain-blood barrier (I think that is what it is called) and changes it to ascorbic acid in the brain. When it has been changed to dehydroascorbic acid, it will then pass back. Maybe it is not illegal to sell dehydroascorbic acid alone or in combination with ascorbic acid.
    Gadget Gainer

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