Sandy, my tests show that glycin is only slightly soluble in propylene glycol - even at elevated temperatures.Originally Posted by sanking
However, propylene glycol still might be a good way to keep premeasured amounts of glycin stable by preventing or retarding oxidation(even though only a small percentage dissolves in the PG). It is worth trying (before my current supply of glycin goes bad).
Glycin does dissolve in triethanolamine (TEA) at high temperatures. However, a TEA/glycin stock solution that I recently mixed (about 2 weeks ago) has changed color and separated into two distinct layers. I need to test the stuff and see if it is still active.