A presumptive test for amphetamines and alkaloids. The Mandelin reagent is a 1% solution of ammonium vanadate (NH4VO3) in concentrated sulphuric acid. Different substances give different colours. Mescaline, for example, produces an orange colour, heroin a brown colour, and amphetamine a blue-green colour. The Mandelin test and Mandelin reagent were discovered by Kurt Friedrich Mandelin (1854–1906).