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

barbiturates Barbiturates are a class of depressant drugs that are chemically derived from barbituric acid. They are effective when used medically as anxiolytics, hypnotics, and anticonvulsants, but have physical and psychological addiction potential as ...

. It is composed of a mixture of two solutions. Part A is 0.1 g of cobalt(II) acetate dihydrate dissolved in 100 ml of

methanol Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical compound and the simplest aliphatic Alcohol (chemistry), alcohol, with the chemical formula (a methyl group linked to a hydroxyl group, often ab ...

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 compone ...

. Part B made up of is 5%

isopropylamine Isopropylamine (also known as monoisopropyl amine, MIPA, or 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 c ...

(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 ...

pentobarbital Pentobarbital (US) or pentobarbitone (British and Australian) 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 insomnia but ...

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, sold under the brand name Seconal among others, is a short-acting barbiturate drug originally used for the treatment of insomnia. It was patented by Eli Lilly and Company in 1934 in the United States. It possesses anesthetic, antic ...

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