Australia's Science Forum

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?

try amylase, or just iodine solution ( do not add potassium iodide)

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.

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