Liebermann reagent explained
The Liebermann reagent named after Hungarian chemist Leo Liebermann (1852-1926) is used as a simple spot-test to presumptively identify alkaloids as well as other compounds. It is composed of a mixture of potassium nitrite and concentrated sulfuric acid.[1] [2] 1 g of potassium nitrite is used for every 10 mL of sulfuric acid.[3] Potassium nitrite may also be substituted by sodium nitrite.[4] [5] It is used to test for cocaine, morphine, PMA and PMMA.
The test is performed by scraping off a small amount of the substance and adding a drop of the reagent (which is initially clear and colorless). The results are analyzed by viewing the color of the resulting mixture, and by the time taken for the change in color to become apparent.
Final colors produced by Liebermann Reagent with various substances| Substance | Color |
|---|
| No reaction |
| Yellowish |
| Black |
| Red - orange |
| Blue |
| Purple - brown[6] |
| Intense brown - black |
| Orange to red[7] |
| Red[8] |
| Orange[9] [10] |
| Bright yellow[11] |
| Bright yellow |
| Bright yellow |
| Faint yellow |
| No reaction |
| Faint orange |
| Orange > brown |
| Yellow > green |
| Orange[12] |
| Yellow |
| Orange |
| Yellow |
| Yellow |
| Yellow |
| Yellow > brown or green > brown |
| Orange |
| Brown |
| Orange |
| Dark yellow |
| Dark yellow |
| Dark green |
| Black (bubbling) |
| Dark red |
| Yellow brown |
| Dark brown |
| Light brown |
| Dark yellow |
| Red-orange > dark red |
| Red-orange > dark red |
| Red-orange > dark red |
| Dark red |
| No color change |
| Yellow - brown |
| Yellow - brown |
| Dark yellow - brown |
| Yellow - brown |
| Yellow - orange |
| RCS-4-C4 homolog | Brown |
| Dark yellow |
| Green - brown |
| Yellow |
| Brown |
| Brown |
| Orange - brown |
| Pale yellow |
| Dark brown |
| Dark brown - black |
| Brown |
| Black |
| Black |
| Black |
| Black |
| Dark brown |
| Black |
| Dark brown |
| Black |
| Dark purple |
| Dark red |
| Dark brown |
| Green > black |
| Dark brown |
| Red - orange[13] |
| Black |
| Brown - black |
| Red |
| Green |
| Yellow > black > clear |
| Yellow → black |
| Green | |
See also
Notes and References
- Book: Horowitz . Benjamin . A Study of the Action of Ammonia on Thymol . Bibliolife . 2009 . 26 . 2012-01-25 . 978-1-110-61089-1 . Since his day the Liebermann reagent (6% potassium nitrite in conc. sulfuric acid) has been extensively used. .
- Book: Bell . Suzanne . Dictionary of Forensic Science (Facts on File Science Dictionary) (Facts on File Science Dictionary Series.) . Facts on File Inc . 30 Jun 2004 . 142 . 2012-01-25 . 978-0-8160-5131-1 .
- Book: Brittain . Harry G. . McLeish . Michael J . Analytical Profiles of Drug Substances and Excipients . 25 . Academic Press . 20 Mar 1998 . 106 . 978-0-12-260825-4.
- Web site: Archived copy . Liebermann Reagent: Carefully add 5 g sodium nitrite to 50 mL sulfuric acid with cooling and swirling. . 2015-02-01 . https://web.archive.org/web/20150201111444/http://www.austintexas.gov/sites/default/files/files/Police/DC_Technical_Manual_100114.pdf . 2015-02-01 . dead .
- Book: Drugs and Poisons in Humans: A Handbook of Practical Analysis. 9783540275794. Liebermann's reagent: 2 g of sodium nitrate is dissolved in 20 mL of concentrated sulfuric acid.. Suzuki. Osamu. Watanabe. Kanako. 16 January 2006. Springer .
- Book: EMCDDA . EMCDDA Risk Assessment: Report on the Risk Assessment of PMMA in the Framework of the Joint Action on New Synthetic Drugs . Dictus Publishing . 30 Mar 2011 . 54 . 2012-01-25 . 978-3-8433-2695-7.
- Web site: How to test AMPHETAMINE?. 28 September 2020.
- Web site: NARK® II Narcotics Test - NARK20031 - Liebermann Reagent - Meth/Morphine . 11 December 2015.
- Uchiyama N, Kawamura M, Kamakura H, Kikura-Hanajiri R, Goda Y . Analytical Data of Designated Substances Controlled by the Pharmaceutical Affairs Law in Japan, Part II: Color Test and TLC . Yakugaku Zasshi . 128 . 6 . 981–7 . 2008 . 10.1248/yakushi.128.981 . 18520145 . PDF . free .
- Web site: 4-FA reaction colour results with liebermann and froehde reagent test kits . Reagent Tests UK . 3 January 2016 . 29 February 2016.
- Toole KE, Fu S, Shimmon RG, Kraymen N . Color Tests for the Preliminary Identification of Methcathinone and Analogues of Methcathinone . Microgram Journal . 9 . 1 . 27–32 . 2012 .
- Web site: Color Tests and Analytical Difficulties With Emerging Drugs of Abuse. Johnson County Sheriff’s Office Criminalistics Laboratory. 2013-07-16. 2012.
- Web site: Rapid Testing Methods of Drugs of Abuse. United Nations International Drug Control Programme. 2013-07-16. 2012.
