My experience of glycin is similar, in a sealed container at low temperature it keeps well. Alternatively it keeps in solution , probably better still in the bisulfite you suggest.
http://thaimonochrome.tripod.com/library/chemical/bulk_chem/glycin.html
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.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?
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.
Metol is a sulfate salt, whereas Glycin is sold without an anion from a mineral acid. Would Glycin not dissolve in PPG directly?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
Would Glycin not dissolve in PPG directly?
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.
I did not have success dissolving Glycin in Metabisulfite or numerous other chemical solutions. But this approach works. Using this chemical equation: 2 Sodium Hydroxide + 1 Sodium Metabisulfite = 2 Sodium Sulfite + 1 water. I've tried 100ml H2O, add 1 gram NaOH, dissolve 3 grams Glycin, then add 2.38 g Na2S2O5 which yields 3.15 g Na2SO3 in solution with the Glycin. I don't know how long this preserves the Glycin. Or how much Glycin one could dissolve in this volume. The same approach can be done with KOH & NaHSO3 but with different weights of chemicals.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?
This thread has answered a question for me. I recently mixed up a batch of Ansco 130, the Glycin was about 5 years old, it had been stored at room temp in my darkroom. Whilst it seemed to develop fine and there was no discolouration of the white border it left some nasty stains on my developing tray. Sounds like I better get a fresh tub of Glycin and store it in the fridge.
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?
As long as the glycin was still pale gray it was probably fine. It easily keeps 5 years in the deep freezer.
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"
From an even older post (can't remember where):
If you mix the glycin with a small amount of 99% TEA, about half the mass of the glycin, it will become soluble in glycol.
This TEA trick is indeed very useful for me.
..........
.....................................From an even older post (can't remember where):
If you mix the glycin with a small amount of 99% TEA, about half the mass of the glycin, it will become soluble in glycol.
Any news to report on your long term preservation results? And if so, what is the strategy you settled on?
I didn't actually try the TEA trick if that's what you are interested in knowing. In the end I stored Glycin in the refrigerator and it seemed to be keeping well when I checked last year.
The TEA trick was the trick I was interested in. Nevertheless, it is good to hear that storing Glycin in a fridge works as well. A general household fridge, or something more industrial?
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