Dille–Koppanyi reagent explained

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 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.^{[1] [2]} 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, 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).^{[4] [5]}

See also

• Drug checking
• Marquis reagent
• Froehde's reagent
• Zwikker reagent

Notes and References

1. O’Neal . C. L. . Crouch . D. J. . Fatah . A. A. . 10.1016/S0379-0738(99)00235-2 . Validation of twelve chemical spot tests for the detection of drugs of abuse . Forensic Science International . 109 . 3 . 189–201 . 2000 . 10725655.
2. Web site: Color Test Reagents/Kits for Preliminary Identification of Drugs of Abuse. Law Enforcement and Corrections Standards and Testing Program. 2011-07-24. July 2000.
3. Web site: Unit 9: Crime - Reagent Kits . 2014-03-17 . Lancashire . Robert J. . 2011-10-13 . University of the West Indies, Mona Campus.
4. Koppanyi . T. . Dille . J. M. . Murphy . W. S. . Krop . S. . Studies on barbiturates. II. Contributions to methods of barbital research . 10.1002/jps.3080231103 . Journal of the American Pharmaceutical Association . 23 . 11 . 1074–1079. 1934.
5. Dille . J. M. . Koppanyi . T. . 10.1002/jps.3080231104 . Studies on barbiturates. III. Chemical assay of barbiturates . Journal of the American Pharmaceutical Association . 23 . 11 . 1079–1084. 1934.