Ask A Scientist Chemistry Archive

name        Isaac
status       student
grade        6-8
location     CA

Question -   Is there an easily obtainable chemical that indicates the
presence of  caffeine?
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Here is a identification method from the USP, not sure if you'll be able to
get these chemicals but it's worth a try:
Dissolve about 5 mg in 1 mL of hydrochloric acid in a porcelain dish, add 50
mg of potassium chlorate, and evaporate on a steam bath to dryness. Invert
the dish over a vessel containing a few drops of 6 N ammonium hydroxide: the
residue acquires a purple color, which disappears upon the addition of a
solution of 1 N sodium hydroxide.

Not sure if your substance is a powder or liquid, but if it's a liquid,
evaporate to dryness enough of the liquid that would contain about 5-10 mg
of caffeine and then dissolve this residue with 10 mL of chloroform and 3
drops of ammonium hydroxide, and filter through a porous paper filter.  Then
evaporate this to dryness and perform the method below on the residue
containing about 5-10 mg of caffeine: 

Joel Jadus
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