Quote Originally Posted by albada View Post
I mixed a new batch of XTOL a couple of days ago, storing it in five 1-litre bottles. And I thought of a way of making it last longer: Store the extra bottles in the refrigerator. Sulfite will precipitate out of solution, but when it's time to start a new bottle, warming and shaking it should bring the precipitate back into solution. Kirk Keys reminded me that chemical reactions proceed half as fast with each 10C temperature-drop, so refrigeration should make XTOL last around 1.5-2 years instead of 6 months. Is there any reason why this would not work?

Mark Overton
Mark,
Xtol in full sealed glass bottles (no oxidation from air) is reported to last 7 1/2 years:
http://www.apug.org/forums/forum37/1...ties-xtol.html
The 6 months figure you quote is for part full bottles with air oxidation of ascorbate.The chelating agent is to slow down this oxidation.
In full sealed bottles Xtol can only decompose by hydrolysis, not oxidation.Ascorbate hydrolysis is probably not significant ,Dimezone S is more resisistant to hydrolysis than phenidone.