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
Alprazolam
No reaction
Cocaine
Yellowish[2]
Morphine
Black[2][6]
Atropine
Red - orange[citation needed]
Yohimbine
Blue[citation needed]
PMA and PMMA
Purple - brown[7]
MDMA
Intense brown[8] - black[7]
Amphetamine
Orange to red[9]
Methamphetamine
Red[6]
4-FA
Orange[10][11]
Cathinone
Bright yellow[8]
Methcathinone
Bright yellow[8]
4-MMC
Bright yellow[8]
N,N-DMC
Faint yellow[8]
3-FMC
No reaction[8]
4-MOMC
Faint orange[8]
Methylone
Orange > brown[8]
MDPV
Yellow > green[8]
4-Me-PPP
Orange[12]
Brephedrone
Yellow[12]
4-MEC
Orange[12]
Pentedrone
Yellow[12]
4-Methylbuphedrone
Yellow[12]
Buphedrone
Yellow[12]
Butylone
Yellow > brown[12] or green > brown[8]
3,4-DMMC
Orange[12]
Naphyrone
Brown[12]
Benzedrone
Orange[12]
JWH-307
Dark yellow[12]
AB-001
Dark yellow[12]
CB-13
Dark green[12]
JTE-907
Black (bubbling)[12]
UR-144
Dark red[12]
URB-597
Yellow brown[12]
URB602
Dark brown[12]
URB754
Light brown[12]
AM-1248
Dark yellow[12]
AB-034
Red-orange > dark red[12]
A-796,260
Red-orange > dark red[12]
A-834,735
Red-orange > dark red[12]
FUR-144
Dark red[12]
APINACA
No color change[12]
JWH-073
Yellow - brown[12]
JWH-018
Yellow - brown[12]
JWH-200
Dark yellow - brown[12]
AM-2201
Yellow - brown[12]
JWH-203
Yellow - orange[12]
RCS-4-C4 homolog
Brown[12]
AM-694
Dark yellow[12]
MAM-2201
Green - brown[12]
AM-2233
Yellow[12]
STS-135 (drug)
Brown[12]
4-MeO-PCP
Brown[12]
Methoxetamine
Orange - brown[12]
Ethketamine
Pale yellow[12]
3-HO-PCE
Dark brown[12]
5-MeO-DALT
Dark brown - black[12]
4-methyl-aET
Brown[12]
4-AcO-DALT
Black[12]
4-HO-MET
Black[12]
4-HO-MIPT
Black[12]
4-AcO-DET
Black[12]
DPT
Dark brown
aMT
Black[12]
5-IT
Dark brown[12]
5-APB
Black[12]
6-APB
Dark purple[12]
Camfetamine
Dark red[12]
Methiopropamine
Dark brown[12]
MDAI
Green > black[12]
5-IAI
Dark brown[12]
Pethidine
Red - orange[13]
Mescaline
Black[13]
Allylescaline
Brown - black[12]
2C-T-2
Red[12]
2C-P
Green[12]
2C-C
Yellow > black > clear
2C-B
Yellow → black
b-methoxy-2C-D
Green[12]
^Horowitz, Benjamin (2009). A Study of the Action of Ammonia on Thymol. Bibliolife. p. 26. ISBN 978-1-110-61089-1. Retrieved 2012-01-25. Since his day the Liebermann reagent (6% potassium nitrite in conc. sulfuric acid) has been extensively used.
^ abcBell, Suzanne (30 Jun 2004). Dictionary of Forensic Science (Facts on File Science Dictionary) (Facts on File Science Dictionary Series.). Facts on File Inc. p. 142. ISBN 978-0-8160-5131-1. Retrieved 2012-01-25.
^Brittain, Harry G.; McLeish, Michael J (20 Mar 1998). Analytical Profiles of Drug Substances and Excipients. Vol. 25. Academic Press. p. 106. ISBN 978-0-12-260825-4.
^"Archived copy" (PDF). Archived from the original (PDF) on 2015-02-01. Retrieved 2015-02-01. Liebermann Reagent: Carefully add 5 g sodium nitrite to 50 mL sulfuric acid with cooling and swirling.{{cite web}}: CS1 maint: archived copy as title (link)
^Suzuki, Osamu; Watanabe, Kanako (16 January 2006). Drugs and Poisons in Humans: A Handbook of Practical Analysis. ISBN 9783540275794. Liebermann's reagent: 2 g of sodium nitrate is dissolved in 20 mL of concentrated sulfuric acid.
^ ab"NARK® II Narcotics Test - NARK20031 - Liebermann Reagent - Meth/Morphine". Retrieved 11 December 2015.
^ abEMCDDA (30 Mar 2011). EMCDDA Risk Assessment: Report on the Risk Assessment of PMMA in the Framework of the Joint Action on New Synthetic Drugs. Dictus Publishing. p. 54. ISBN 978-3-8433-2695-7. Retrieved 2012-01-25.
^ abcdefghijToole KE, Fu S, Shimmon RG, Kraymen N (2012). "Color Tests for the Preliminary Identification of Methcathinone and Analogues of Methcathinone" (PDF). Microgram Journal. 9 (1): 27–32.
^"How to test AMPHETAMINE?". 28 September 2020.
^Uchiyama N, Kawamura M, Kamakura H, Kikura-Hanajiri R, Goda Y (2008). "Analytical Data of Designated Substances Controlled by the Pharmaceutical Affairs Law in Japan, Part II: Color Test and TLC" (PDF). Yakugaku Zasshi. 128 (6): 981–7. doi:10.1248/yakushi.128.981. PMID 18520145.
^"4-FA reaction colour results with liebermann and froehde reagent test kits". Reagent Tests UK. 3 January 2016. Retrieved 29 February 2016.
^ abcdefghijklmnopqrstuvwxyzaaabacadaeafagahaiajakalamanaoapaqarasatauavawaxayazbabbbcbd"Color Tests and Analytical Difficulties With Emerging Drugs of Abuse" (PDF). Johnson County Sheriff’s Office Criminalistics Laboratory. 2012. Retrieved 2013-07-16.
^ ab"Rapid Testing Methods of Drugs of Abuse" (PDF). United Nations International Drug Control Programme. 2012. Retrieved 2013-07-16.
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