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Old 12-30-2005, 05:17 PM
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Post actually you can make it yourself

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
"Oh how wrong we were to think that immortality meant never dying."
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