Dille–Koppanyi reagent

The Dille–Koppanyi reagent is used as a simple spot-test to presumptively identify barbiturates.

Part A is 0.1 g of cobalt(II) acetate dihydrate dissolved in 100 ml of methanol mixed with 0.2 ml of glacial acetic acid.

Part B made up of is 5% isopropylamine (v/v) in methanol.

The test turns phenobarbital, pentobarbital, amobarbital and secobarbital light purple[1] by complexation of cobalt with the barbiturate nitrogens.

[3] The test, in a slightly different formulation, was developed in the 1930s by the Hungarian-American pharmacologist Theodore Koppanyi (1901–1985) and the American Biochemist, James Madison Dille (1928–1986).