Starch - negative test

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sunray18
Posts: 1488
Joined: 14 Feb 2008, 12:30
State/Location: NSW

Starch - negative test

Post by sunray18 »

teacher wants a test that will show a negative result for Starch. It is for a prac exam. He wants starch and water for the solutions to be tested. One test reagent will be iodine, but for the other one he wants 'something ' that will not react with starch.
He doesn't want to use any heating elements so it can't be the Benedict's reagent.
He is not happy with Biuret test - ANYONE have any ideas?
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Jazz
Posts: 468
Joined: 24 Jul 2006, 10:00
State/Location: NSW

Re: Starch - negative test

Post by Jazz »

try amylase, or just iodine solution ( do not add potassium iodide)
Cheers Jazz
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dime
Posts: 703
Joined: 13 Jun 2007, 09:55
State/Location: NSW

Re: Starch - negative test

Post by dime »

This may be too late, but if you mean another indicator, you could use anything from Alizarin Yellow thru to Universal Indicator. I was thinking of Methyl Orange but I haven't tried it, but I doubt if any of them would react.
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sunray18
Posts: 1488
Joined: 14 Feb 2008, 12:30
State/Location: NSW

Re: Starch - negative test

Post by sunray18 »

Thanks to you all - I talked the teacher out of this!
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