Glycin Solubility

[Raghu Kuvempunagar]

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?

 

[Steve Goldstein]

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.

 

[Alan Johnson]

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

 

[Raghu Kuvempunagar]

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

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?

 

[DREW WILEY]

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.

 

[Alan Johnson]

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.

 

[Raghu Kuvempunagar]

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.

Thanks Alan.

 

[Rudeofus]

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

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

 

[Raghu Kuvempunagar]

Would Glycin not dissolve in PPG directly?

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."

 

[Alan Johnson]

Did we discover that glycin is amphoteric like p-aminophenol ?
https://hpvchemicals.oecd.org/ui/handler.axd?id=9addb354-2ae7-4b04-9156-618472148207

 

[Steve Goldstein]

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.

 

[Raghu Kuvempunagar]

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.

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.

 

[Stephen Jeffery]

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?

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.

 

[Nokton48]

Rats. I want to mix up some 130, but my Glycin is twenty five years old. Prolly no good?

 

[markbau]

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.

 

[L Gebhardt]

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 found Ansco 130 does stain the developer tray, even if it's fresh. I keep mine around for ages and replenish it as I use it. As it seasons it stains the trays a bit more, but never stains the prints. As long as the glycin was still pale gray it was probably fine. It easily keeps 5 years in the deep freezer.

 

[Pixophrenic]

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?

For whatever it is worth, I have been asking myself the same question. In another thread I suggested that the silver halide solvent effect I saw may be an effect of glycin decomposition product (awaiting a fresh glycin batch now). Having tried various ways to preserve glycin in a stock solution I found that 5% solution in 5% sulfite, stored in aliquots, does not change color appreciably in at least 6 months (and counting). Then again this is also true for D78 developer stored in tightly closed small aliquots.

 

[Nokton48]

As long as the glycin was still pale gray it was probably fine. It easily keeps 5 years in the deep freezer.

Mine is 25-30 years old, a rusty orange brown color.

Threw it out, replacing with fresh which I ordered from FF, along with some Amidol.

 

[ritternathan]

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.

 

[Raghu Kuvempunagar]

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.

@ritternathan: I had somehow missed both your post as well as the one you quoted. This TEA trick is indeed very useful for me. Thanks a lot!

 

[removedacct3]

This TEA trick is indeed very useful for me.

Any news to report on your long term preservation results? And if so, what is the strategy you settled on?

 

[john_s]

..........
.....................................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.

Does it still work in developer formulas then?

 

[Raghu Kuvempunagar]

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.

 

[removedacct3]

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?

 

[Steve Goldstein]

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?

I store my Glycin in our household freezer, which is set at -6C. The bottle is at least two years old and it's still fine, the powder is only the very slightest gray color. Whether you refrigerate it or freeze it, make sure to take it out a day before you want to use it so it's up to room temperature.