Zimmermann reagent

The Zimmermann reagent is used as a simple spot-test used in chromatography to presumptively identify alkaloids, especially benzodiazepines, as well as other compounds. It is therefore used in drugs testing.{{cite book|last1=Janák|first1=Zdeněk Deyl, Karel Macek, Jaroslav|title=Liquid Column Chromatography a Survey of Modern Techniques and Applications.|date=1975|publisher=Elsevier|location=Burlington|isbn=9780080858036|page=603|url=https://books.google.com/books?id=P_MVjTFh16YC&pg=PA603|access-date=10 January 2016}}{{cite book|title=Steroid Dynamics: Proceedings of the Symposium on the Dynamics of Steroid Hormones Held in Tokyo, May, 1965|date=31 January 2017|publisher=Academic Press|isbn=9781483270852|page=381|url=https://books.google.com/books?id=3s43BQAAQBAJ&pg=PA381|access-date=10 January 2016}}{{cite book|last1=Callow|first1=R.K.|last2=Campbell|first2=P.N.|last3=Datta|first3=S.P|title=The Chromatography of Steroids: International Series of Monographs on Pure and Applied Biology: Biochemistry|date=2013|publisher=Elsevier|isbn=9781483184579|pages=232, 270|url=https://books.google.com/books?id=si3-BAAAQBAJ&pg=PA232|access-date=10 January 2016}}

It is a two-component reagent, with the first component composed of 1,3-dinitrobenzene (1% w/v) in methanol and the second component composed of 15% potassium hydroxide in water.{{cite web | url=https://www.unodc.org/documents/scientific/barbiturates_and_benzodiazepines.pdf | title=Recommended methods for the I dentification and A nalysis of Barbiturates and Benzodiazepines under International Control | publisher=UNODC | date=2012 | access-date=10 January 2016 | pages=25}}{{cite web | url=https://www.unodc.org/pdf/publications/st-nar-13-rev1.pdf | title=Rapid Testing Methods of Drugs of Abuse | publisher=UNODC | date=1994 | access-date=10 January 2016 | pages=103}}0-471-49252-3

One drop of each component is added to the sample being tested and the resulting colour change is observed to give an indication of the identity of the compound.

The reagent works by forming a reddish-purple Meisenheimer complex at C3 for diazepines with a carbonyl at C2 and an alkyl group at N1.{{cite web | url=https://www.unodc.org/pdf/scientific/SCITEC6.pdf | title=Chemistry and Reaction Mechanisms of Rapid Tests for Drugs of Abuse and Precursors Chemicals | publisher=UNODC | date=February 1989 | access-date=3 January 2016 |author1=Kovar, Karl-Artur |author2=Laudszun, Martina |name-list-style=amp | pages=13}} Without these groups it is not possible to form the methylene compound which reacts with dinitrobenzene but triazolo compounds may react.

It is named for the American biochemist Robert Zimmermann (b.1937).