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Old 10-19-2008, 08:15 AM
isafr2 isafr2 is offline
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Originally Posted by boring_sister View Post
i found how to prepare one on the same site where you found the project

directions for the preparation of vitamin c indicators

* add 2 g of corn starch or potato starch in 200 ml of cold, distilled water. Bring the mixture to a full boil in a glass beaker.
* to 1 liter of water, add 8 ml of the starch solution and 1 ml of tincture of iodine.
* note: The color of the starch indicator should be a royal blue. Just before doing the lab, check the indicator and dilute the concentration so that a workable number of drops of fresh orange juice (5 to 25) turn the indicator colorless.

Tincture of iodine

* add 2 g of iodine to 45 ml of ethanol and dissolve.
* dissolve this mixture in 55 ml of distilled water.
* add 2.4 grams of ki to this mixture and dissolve.


* stock solution : Dissolve 100 mg of 2,6 dichloro-indophenol salt in 100 ml of distilled water.
* prepare a working solution by diluting the stock solution at a 1:10 ration with distilled water.
* note: When testing the juices of citrus fruits for vitamin c content, the blue indophenol may turn pink before turning colorless because of the presence of substances other than vitamin c.

Good huh
the more drops the more vitamin c
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