The Dille–Koppanyi reagent is used as a simple spot-test to presumptively identify barbiturates. It is composed of a mixture of two solutions. Part A is 0.1 g of

cobalt(II) acetate Cobalt(II) acetate is the cobalt salt of acetic acid. It is commonly found as the tetrahydrate Co(CH3CO2)2·4 H2O, abbreviated Co(OAc)2·4 H2O. It is used as a catalyst. Synthesis and structure Like many other transition metal acetates, cobalt(I ...

dihydrate dissolved in 100 ml of methanol mixed with 0.2 ml of

glacial acetic acid Acetic acid , systematically named ethanoic acid , is an acidic, colourless liquid and organic compound with the chemical formula (also written as , , or ). Vinegar is at least 4% acetic acid by volume, making acetic acid the main component ...

. Part B made up of is 5%

isopropylamine Isopropylamine (monoisopropyl amine, MIPA, 2-Propylamine) is an organic compound, an amine. It is a hygroscopic colorless liquid with ammonia-like odor. It is miscible with water and flammable. It is a valuable intermediate in chemical industry. ...

(v/v) in methanol. Two drops of A are dropped onto the substance followed by one drop of B and any change in colour is observed. The test turns

phenobarbital Phenobarbital, also known as phenobarbitone or phenobarb, sold under the brand name Luminal among others, is a medication of the barbiturate type. It is recommended by the World Health Organization (WHO) for the treatment of certain types of ep ...

pentobarbital Pentobarbital (previously known as pentobarbitone in Britain and Australia) is a short-acting barbiturate typically used as a sedative, a preanesthetic, and to control convulsions in emergencies. It can also be used for short-term treatment of i ...

amobarbital Amobarbital (formerly known as amylobarbitone or sodium amytal as the soluble sodium salt) is a drug that is a barbiturate derivative. It has sedative-hypnotic properties. It is a white crystalline powder with no odor and a slightly bitter taste. ...

and

secobarbital Secobarbital (as the sodium salt, originally marketed by Eli Lilly and Company for the treatment of insomnia, and subsequently by other companies as described below, under the brand name Seconal) is a short-acting barbiturate derivative drug that ...

light purple by complexation of cobalt with the barbiturate nitrogens. 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).

References

Chemical tests Analytical reagents Drug testing reagents {{analytical-chemistry-stub

See also

References