Glycin Solubility

Discussion in 'B&W: Film, Paper, Chemistry' started by Raghu Kuvempunagar, Nov 8, 2018 at 6:24 AM.

  1. Raghu Kuvempunagar

    Raghu Kuvempunagar Member
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    I've read that Glycin is sparingly soluble in plain water but is readily soluble in alkaline or acidic solutions. Can a liter of 1% solution of Sodium Metabisulphite be used to dissolve 10 or more grams of Glycin? Would such a solution preserve Glycin for a year or more? What's your recipe for dissolving and preserving Glycin?
     
  2. Steve Goldstein

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    My glycin stays in powder form in the freezer, which maintains at -6C. The container is about 5 years old at this point and every batch of Ansco 130 I mix up works just fine.
     
  3. Alan Johnson

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    Raghu Kuvempunagar

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    Alan, from a really old apug thread: "2g glycin, 6ml TEA, 1tsp water, on heating gently and stirring this formed a clear solution which dissolved in 14 ml propylene glycol." Do you remember if this resulted in a stable solution?
     
  5. DREW WILEY

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    Unopened glycin powder needs to be kept frozen. I would never attempt to keep it around in solution. It dissolves easily enough at time of use. So I don't know what the fuss is about.
     
  6. Alan Johnson

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    I still have that sample stored in a 35mm film canister, presumed airtight.It has only darkened to coffee color so I would guess it is OK. IIRC Pat Gainer was the first to find that metol had to be reacted with TEA and water before it would dissolve in propylene glycol. I copied his method and dissolved glycin . But,as others have said, if you can keep glycin at low temperature in a sealed container it should be adequate for most purposes.
     
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    Raghu Kuvempunagar

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    Thanks Alan.
     
  8. Rudeofus

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    Metol is a sulfate salt, whereas Glycin is sold without an anion from a mineral acid. Would Glycin not dissolve in PPG directly?
     
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    Raghu Kuvempunagar

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    Quoting Tom Hoskinson from a very old apug thread:
    "I have determined by test that Glycin is not soluble in propylene glycol or ethylene glycol (up to 300 F). Glycin also was not soluble in methanol, isopropanol or ethyl alcohol."
     
  10. Alan Johnson

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  11. Steve Goldstein

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    A quick correction - my freezer is set to -6F, which is around -20C, not the -6C I stated earlier. And that’s where my glycin and amidol are stored. I take them out a day ahead of time when I need to mix up a new batch.
     
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    Raghu Kuvempunagar

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    Thanks Steve. Storing Glycin or any other photochemical in the freezer is not practical in my case for some reasons. Hence I was looking for ways of preserving Glycin in a solution. Looks like there are several possibilities - TEA+water+glycol, metabisulphite+water.
     
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