I have just undertaken an A/B extraction on some Acacia Floribunda bark and its currently at the freeze precipitation stage.
Four pulls were done using warm shellite and each pull took on a very clear yellow colour in the separatory funnel. Once transferred into a beaker I blew across the top of it and noticed white precipitation followed by the whole lot clouding over into a yellow/green(?) colour.
This was put into the freezer for around 24 hours and the last picture below is what remained in the beaker after the shellite was decanted off. Not long after it looked as if it were starting to melt.
In hindsight, I probably should have just left it to dry as I'm sure it would have recrystalised and been ok, but I ended up re-adding the shellite and putting it back in the freezer for a couple of reasons.
The first reason was, I noticed that when I blew across the top of the shellite it clouded with precipitate again so it appeared that it still needed longer.
The second reason was that I assumed the freezer was set to its coldest setting, which it wasn't...you know what they say about making assumptions.
so that has now been rectified.
Anyway, with a slightly colder freezer I'm hoping the results will improve by this time tomorrow but if my freezer isn't cold enough I might attempt freeze precipitation with dry ice.
Does anyone recommend using dry ice or would it be better just to let it evaporate?
Four pulls were done using warm shellite and each pull took on a very clear yellow colour in the separatory funnel. Once transferred into a beaker I blew across the top of it and noticed white precipitation followed by the whole lot clouding over into a yellow/green(?) colour.
This was put into the freezer for around 24 hours and the last picture below is what remained in the beaker after the shellite was decanted off. Not long after it looked as if it were starting to melt.
In hindsight, I probably should have just left it to dry as I'm sure it would have recrystalised and been ok, but I ended up re-adding the shellite and putting it back in the freezer for a couple of reasons.
The first reason was, I noticed that when I blew across the top of the shellite it clouded with precipitate again so it appeared that it still needed longer.
The second reason was that I assumed the freezer was set to its coldest setting, which it wasn't...you know what they say about making assumptions.
so that has now been rectified.Anyway, with a slightly colder freezer I'm hoping the results will improve by this time tomorrow but if my freezer isn't cold enough I might attempt freeze precipitation with dry ice.
Does anyone recommend using dry ice or would it be better just to let it evaporate?