Mandelin reagent
The Mandelin reagent is used as a simple spot-test to presumptively identify alkaloids as well as other compounds. It is composed of a mixture of ammonium metavanadate and concentrated sulfuric acid. Its primary use is for the detection of ketamine and PMA It is unusual among reagent tests that it has a very strong yellow colour prior to being used for testing, which forms within about 48 hours of mixing.