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 g of potassium nitrite is used for every 10 mL of sulfuric acid. Potassium nitrite may also be substituted by sodium nitrite. 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 substancesSubstanceColorAlprazolam No reactionCocaine YellowishMorphine BlackAtropine Red - orangeYohimbine BluePMA and PMMA Purple - brownMDMA Intense brown - blackAmphetamine Orange to redMethamphetamine Red4-FA OrangeCathinone Bright yellowMethcathinone Bright yellow4-MMC Bright yellowN,N-DMC Faint yellow3-FMC No reaction4-MOMC Faint orangeMethylone Orange > brownMDPV Yellow > green4-Me-PPP OrangeBrephedrone Yellow4-MEC OrangePentedrone Yellow4-Methylbuphedrone YellowBuphedrone YellowButylone Yellow > brown or green > brown3,4-DMMC OrangeNaphyrone BrownBenzedrone OrangeJWH-307 Dark yellowAB-001 Dark yellowCB-13 Dark greenJTE-907 Black (bubbling)UR-144 Dark redURB-597 Yellow brownURB602 Dark brownURB754 Light brownAM-1248 Dark yellowAB-034 Red-orange > dark redA-796,260 Red-orange > dark redA-834,735 Red-orange > dark redFUR-144 Dark redAPINACA No color changeJWH-073 Yellow - brownJWH-018 Yellow - brownJWH-200 Dark yellow - brownAM-2201 Yellow - brownJWH-203 Yellow - orangeRCS-4-C4 homolog BrownAM-694 Dark yellowMAM-2201 Green - brownAM-2233 YellowSTS-135 (drug) Brown4-MeO-PCP BrownMethoxetamine Orange - brownEthketamine Pale yellow3-HO-PCE Dark brown5-MeO-DALT Dark brown - black4-methyl-aET Brown4-AcO-DALT Black4-HO-MET Black4-HO-MIPT Black4-AcO-DET BlackDPT Dark brownaMT Black5-IT Dark brown5-APB Black6-APB Dark purpleCamfetamine Dark redMethiopropamine Dark brownMDAI Green > black5-IAI Dark brownPethidine Red - orangeMescaline BlackAllylescaline Brown - black2C-T-2 Red2C-P Green2C-C Yellow > black > clear2C-B Yellow → blackb-methoxy-2C-D Green
See also Drug checking Liebermann–Burchard test Dille–Koppanyi reagent Folin's reagent Froehde reagent Mandelin reagent Marquis reagent Mecke reagent Simon's reagent Zwikker reagent
References