Marquis reagent

Marquis reagent is used as a simple spot-test to presumptively identify alkaloids as well as other compounds. It is composed of a mixture of formaldehyde and concentrated sulfuric acid, which is dripped onto the substance being tested. The United States Department of Justice method for producing the reagent is the addition of 100 mL of concentrated (95–98%) sulfuric acid to 5 mL of 40% formaldehyde.[1]:12 Different compounds produce different color reactions. Methanol may be added to slow down the reaction process to allow better observation of the colour change.

It was first discovered in 1896[2] and described by the Russian (Estonian) pharmacologist, Eduard Marquis (18711944) (Russian: Эдуард Маркус)[3] in his magister dissertation in 1896;[4] and named after him,[5] and was tested for the first time at the University of Dorpat. The reagent should be stored in the freezer for maximum shelf life[6]

It is the primary presumptive test used in Ecstasy testing kits. It can also be used to test for such substances as opiates (e.g. codeine, heroin), and phenethylamines (e.g. 2C-B, mescaline).

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:


Reagent test results develop very quickly and due to reactions with moisture and oxygen in air, any changes after the first 60 seconds should be discarded.[7]

Marquis reagent test analysis
Substance Color Time (s) Notes
MDMA or MDApurple to black0-5may have dark purple tint
Amphetamine or Methamphetamineorange to brown0-5may have a brown tint
2C-Byellow to green5-10color may change from initial result[7]
DXMgray to black15-30initially no change; takes much longer to reach black than MDMA
Final colors produced by Marquis Reagent with various substances[1]:36[8]
Substance Color
βk-2C-BBright orange
2,5-Dimethoxy-4-bromoamphetamine (DOB)Olive Green - Yellow
2-FMARapidly fizzes and dissolves. Colourless/Light yellow
25C-NBOMeClear (No change)
25B-NBOMeDark Green
4F-MPHNo reaction
5-EAPBPurple to Black
5-MeO-MiPTClear/Light Brown[9]
AspirinPink > Deep Red[10][11][12]
AdrafinilDeep reddish orange - Dark reddish brown
Benzphetamine HClDeep reddish brown
Benzylpiperazine(BZP)Clear (fizzes)
Buprenorphine HCLPinkish violet
Chlorpromazine HClDeep purplish red
CodeineVery dark purple
CaffeineClear (No change)
CocaineClear (No change)
d-Amphetamine HClStrong reddish orange - Dark reddish brown
d-Methamphetamine HClDeep reddish orange - Dark reddish brown
Diacetylmorphine HCl (Heroin)Deep purplish red
Dimethylamylamine (DMAA)No color change (fizzes)
Dimethyltryptamine (DMT)Orange
Dimethoxymethamphetamine HCL (DMMA)Moderate olive
Doxepin HClBlackish red
DristanDark grayish red
ExedrineDark red
LSDOlive black
MethoxetamineSlow pink[8]
3,4-Methylenedioxyamphetamine HCl (MDA)Dark Purple - Black
Methylenedioxy-N-ethylamphetamine HCl (MDEA)Dark Purple - Black
Methylenedioxymethamphetamine HCl (MDMA)Dark Purple - Black
Methylenedioxypropylamphetamine HCl (MDPR)Dark Purple - Black
Methylone (M1/bk-MDMA/MDMC)Yellow
Methylenedioxypyrovalerone (MDPV)Yellow
Pethidine/Meperidine HClDeep brown
Mescaline HClStrong orange
Methadone HClLight yellowish pink
Methylphenidate HClModerate orange yellow
Methylene BlueDark Green
ModafinilYellow/Orange --> Brown[13]
Morphine monohydratedeep purplish red
OpiumDark grayish reddish Brown
Oxycodone HClPale violet
Propoxyphene HClBlackish purple
SugarDark brown


The colour change from morphine is proposed to be a result of two molecules of morphine and two molecules of formaldehyde condensing to the dimeric product which is protonated to the oxocarbenium salt.[14]

See also

Sources for Marquis Reagent

Prism Reagents


  1. "Color Test Reagents/Kits for Preliminary Identification of Drugs of Abuse" (PDF). Law Enforcement and Corrections Standards and Testing Program. July 2000. Retrieved 24 July 2011.
  2. Toxicology. Volume 2 : mechanisms and analytical methods — New York, New York ; San Francisco, California : Academic Press, 1961 — p. 247.
  3. Каталог диссертаций Дерптского Университета с 1811 по 1914 гг. // Ин-т экспериментальной медицины
  4. Marquis, Eduard. Über den Verbleib des Morphin im tierischen Organismus. Magister Dissertation 1896, Jurjew, Arb. Der Pharm. Inst. zu Dorpat 15, 117 (1896);
    Pharmazeutische Zentralhalle für Deutschland., 814 (1896);
    Pharmazeutische Zeitschrift für Russland. 38, 549 (1896).
  5. Юрген Торвальд Сто лет криминалистики — М: Прогресс, 1974
  6. "FAQ". ElevationChemicals. Retrieved 2 December 2018.
  7. "Reagent Testing Instructions". Retrieved 21 December 2016.
  8. Morris, Jeremiah. Color Tests and Analytical Difficulties with Emerging Drugs (PDF). Johnson County Sheriff’s Office Criminalistics Laboratory: NIST. p. 36. Retrieved 10 May 2014.
  9. "EcstasyData 5-MeO-MiPT". EcstasyData.
  10. "Controlled Substances Procedures Manual" (PDF). Virginia Department of Forensic Science. 2013. Retrieved 6 August 2013.
  11. "Color Test Reagents/Kits for Preliminary Identification of Drugs of Abuse" (PDF). Law Enforcement and Corrections Standards and Testing Program. July 2000. Retrieved 24 July 2011.
  12. O’Neal, C. L.; Crouch, D. J.; Fatah, A. A. (2000). "Validation of twelve chemical spot tests for the detection of drugs of abuse". Forensic Science International. 109 (3): 189–201. doi:10.1016/S0379-0738(99)00235-2. PMID 10725655.
  13. Morris, Jeremiah (2004). "Analytical Profile of Modafinil" (PDF). Microgram Journal. 3 (1–2): 28. Retrieved 9 October 2013.
  14. Lancashire, Robert J. (13 October 2011). "Unit 9: Crime - Reagent Kits". University of the West Indies, Mona Campus. Retrieved 17 March 2014.

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