JJay
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How to Stabilize a Starch Suspension
I just prepared a 1% starch suspension, and I'm wondering how to best stabilize it for long storage. My main concern is not so much that the
suspension might settle or gel; rather, I'm concerned about bacteria and fungi growing in it. I don't think a small amount of quaternary ammonium
compound would affect most iodometric titrations (and it probably wouldn't affect any at the three digits of precision I'm doing them at right now),
but I'm not 100% sure.
Any suggestions?
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nezza
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At work we used 0.1% sodium azide as a bacteriostat for most "organic" solutions. It does however react with iodine so any error would need to be
corrected for.
If you're not part of the solution, you're part of the precipitate.
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laserlisa
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One way to stabilize saccharide suspensions is to introduce sulfonate groups on to hydroxyls.
Might be overkill for your applications though.
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JJay
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I just sprayed a little Lysol in the bottle, and it seems to still react as I would expect.
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Tsjerk
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0.02% sodium azide is more than enough.
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CharlieA
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Lange's Handbook stabilizes a 1% solution of starch with a few drops of CHCl3.
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Tsjerk
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But chloroform would evaporate wouldn't it?
10 mM sodium benzoate probably also does the trick and probably is easier to obtain.
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DutchChemistryBox
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A while ago I had the same question.
My solution: just store it in the freezer.
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