Marquis Reagent (English Version)

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The Marquis reagent is a simple analytical method for identifying certain chemical compounds.

Preparation of the Marquis reagent

The original recipe for the Marquis reagent is the following:

9 parts concentrated sulphuric acid (98%) & 1 part formalin (37% formaldehyde in water)

The advice is to add the sulphuric acid to the formaldehyde, and not the other way around. Heat is generated when these two are mixed, with a risk of splattering. It is also advised to only close the vial/flask when the content is fully cooled to room temperature.

Only use glass vials/flasks to store the Marquis reagent. Vial/flasks with glass stoppers are preferred; not all plastics are sulphuric acid resistant!


  • Sulphuric acid is strong corrosive and toxic acid and can damage eyes and skin severely.
  • Formaldehyde is highly toxic and possible carcinogenic. It can be absorbed through the skin. Avoid any direct contact.
  • The Marquis reagent needs to be handled and stored with great care. Only glass and porcelain objects are resistant against the reagent.

Alternative recipes

A disadvantage of the original recipe is the fast and intense colour reaction, which could make it difficult to detect any subtle changes. Therefore methanol is often added to the reagent.

90% concentrated sulphuric acid (98%) & 5% formalin (37% formaldehyde in water) & 5% methanol

Use of the Marquis reagent

Put a drop of the Marquis reagent on glass or porcelain surface. Add of little bit of the desired compound and wait for the colour reaction. Compare the result of the colour reaction with the table below.

Table with the colour reactions

Drug Structure Colour discription Particularities Photo
25B-NBOMe 25bnbome.gif Olive Green Colour turns more Green (± 2 min) Marquis 25bnbome dhp.png
25C-NBOMe 25cnbome.gif Yellow - Orange Marquis 25cnbome dhp.png
25D-NBOMe 25dnbome.gif No colour change
25I-NBOMe 25inbome.gif No colour change
2-AI 2ai.gif Red - Brown Colour turns more Brown (± 2 min) Marquis 2ai dhp.png
2C-B 2c-b 2d.gif Green Colour gets more faint (± 30 min) Marquis 2cb DHP.jpg
2C-C 2cc.gif Light Green - Yellow Colour gets more faint (± 30 min) Marquis 2cc DHP.JPG
2C-D 2cd.gif Yellow - Light Brown Colour disappears (± 30 min) Marquis 2cd DHP.JPG
2C-E 2ce.gif Yellow - Light Brown Colour disappears (± 30 min) Marquis 2ce dhp.png
2C-I 2C-I-structuur.gif Dark Green - Dark Blue Colour turns more Blue (± 5 min) and gets more faint (± 30 min) Marquis 2ci DHP.JPG
2C-P 2C-P.gif Light Brown Colour disappears (± 30 min)
2C-T-2 2ct2.gif Orange - Brown Fizzes Marquis 2ct2 DHP.JPG
2C-T-7 2C-T-7-structuur.gif Light Orange Fizzes Marquis 2ct7 DHP.JPG
2C-T-21 2ct21.gif Light Orange Fizzes Marquis 2ct21 DHP.JPG
2-FMA 2fma.gif Orange - Brown Fizzes first, slow colour reaction (± 60 sec)
2-MeO-Ketamine 2-meo-ketamine.gif Light Pink Marquis 2meoketamine dhp.png
3C-P 3cp.gif Orange - Red Marquis 3cp dhp.png
3-FMC 3fmc.gif No colour change Fizzes
3-MeO-PCP 3meopcp.gif Ligth Blue - Gray Slow colour reaction (± 60 sec), Colour turns more Blue (± 5 min) Marquis 3meopcp dhp.png
4-AcO-DiPT 4-aco-dipt.gif Yellow - Green
4-AcO-DMT 4-aco-dmt.gif Orange - Green (Brown) Colour turns more Brown (± 5 min) Marquis 4acodmt DHP.JPG
4-AcO-MiPT 4-aco-mipt.gif Orange - Green (Brown) Marquis 4acomipt DHP.jpg


4-fmc.gif Light Orange - Light Pink Fizzes Marquis flepedrone DHP.JPG
4-FMP / 4-FA


4-FMP.gif Light Pink Fizzes first, slow colour reaction (± 60 sec) Marquis 4fmp DHP.JPG
4-HO-DALT 4-oh-dalt.gif Yellow - Brown
4-HO-DiPT 4-ho-dipt.gif Orange - Green (Brown) Marquis 4hodipt DHP.jpg
4-HO-MiPT 4-ho-mipt.gif Orange - Green (Brown)
4-MAR 4-MAR.gif Orange Slow colour reaction (± 60 sec)
4-MeO-PCP 4meopcp.gif No colour change


EMA-4.gif Brown Slow colour reaction (± 30 sec) Marquis ema4 DHP.jpg
5-IAI 5iai.gif Orange - Brown
5-MeO-DALT 5-meo-dalt.gif Light Yellow
5-MeO-DiPT 5meodipt.gif Light Orange - Green Marquis 5meodipt DHP.JPG
5-MeO-DMT 5-meo-dmt-structuur.gif Orange - Brown Marquis 5meodmt DHP.jpg
5-MeO-MiPT 5meomipt.gif Yellow - Brown
AET Aet.gif Orange - Brown Colour turns more Brown (± 5 min) Marquis aet DHP.JPG
AH-7921 Ah7921.gif No colour change Fizzes
Alprazolam Alprazolam.gif No colour change
Amphetamine Amfetamine.gif Dark Orange - Brown Marquis amfetamine DHP.JPG
AMT AMT.gif Orange - Brown Colour turns more Brown (± 5 min) Marquis amt DHP.JPG
APPP Appp.gif No colour change
Aspirin Aspirine.gif Red Slow colour reaction (± 2 min) Marquis aspirine DHP.jpg


Bdf.gif Green - Brown Marquis bdf DHP.jpg
Buphedrone Buphedrone.gif No colour change Fizzes
Butylone Butylone.gif Yellow Fizzes Marquis butylone DHP.JPG
BZP Bzp-structuur.gif No colour change Fizzes
Cocaine Cocaïne.gif No colour change
Cafeine Cafeïne.gif No colour change
Codeine Codeine.gif Purple - Black Marquis codeine DHP.JPG
Desoxypipradrol Desoxypipradrol.gif Orange - Red Colour turns Darker (± 5 min) Marquis desoxypipradrol DHP.JPG
Diazepam Diazepam.gif No colour change
DiPT Dipt.gif Yellow - Brown Colour turns Darker (± 5 min) Marquis dipt DHP.JPG
DMT Nn-dmt.gif Yellow - Brown Marquis dmt DHP.JPG
DOC DOC.gif Yellow - Green Marquis doc DHP.jpg
DOI DOI.gif Light Green
DOM DOM.gif Light Yellow Fizzes Marquis dom dhp.jpg
DPT DPT.gif Brown Colour turns more Brown (± 5 min) Marquis dpt DHP.JPG
DXM DXM.gif Black - Grey Slow colour reaction (± 20 sec) Marquis dxm DHP.jpg
Escaline Escaline.gif Orange Colour turns Darker (± 2 min) Marquis escaline dhp.png
Ethaqualone Ethaqualone.gif No colour change
Ethylcathinone Ethylcathinon.gif No colour change Fizzes
Ethylphenidate Ethylfenidaat.gif No colour change Fizzes
Fletamine Fletamine.gif No colour change
Glucose Glucose.gif Dark Brown Slow colour reaction (± 1,5 min) Marquis glucose DHP.JPG
Heroine Heroine.gif Purple - Black
Hydroxyzine Hydroxyzine.gif No colour change
JWH-019 JWH-019.gif Brown Dissolves poorly Marquis jwh019 dhp.png
JWH-073 JWH-073.gif Yellow - Brown Marquis jwh073 DHP.jpg
JWH-200 JWH-200.gif Yellow - Orange Dissolves poorly Marquis jwh200 DHP.jpg
Ketamine Ketamine.gif No colour change
Levamisole Levamisole.gif No colour change Fizzes
MDA MDA.gif Dark Purple - Black Fizzes Marquis mda DHP.JPG
MDAI MDAI.gif Orange - Brown Marquis mdai2 DHP.jpg
MDMA MDMA.gif Dark Purple - Black Marquis mdma DHP.jpg
MDPV MDPV.gif Yellow Fizzes Marquis mdpv DHP.JPG
Mephedrone Mephedrone.gif No colour change Fizzes
Mescaline Mescaline.gif Orange Marquis mescaline DHP.JPG
Methaqualone Methaqualone.gif No colour change
Methoxetamine Methoxetamine.gif No colour change


Methamfetamine.gif Dark Orange - Brown Colour turns more Brown (± 5 min) Marquis meth DHP.JPG
N-Methylephedrine Methyleferdrine.gif Yellow - Light Brown Marquis methylefedrine dhp.jpg
Methylone MDMC.gif Yellow Fizzes Marquis methylone DHP.jpg


Geranamine.gif No colour change Fizzes
Methylphenidate Methylfenidaat.gif Yellow - Orange
Methylmethaqualone Methylmethaqualone.gif No colour change
Modafinil Modafinil.gif Red - Orange (Brown) Colour turns more Brown (± 2 min) Marquis modafinil DHP.JPG
Morphine Morfine.gif Red - Purple


Na-Cl No colour change
Naphyrone Naphyrone.gif Yellow
O-Desmethyltramadol Desmethyltramadol.gif Orange - Red Marquis odesmethyltramadol DHP.jpg


Paracetamol.gif No colour change
Phenazepam Phenazepam.gif No colour change
Phendimetrazine Phendimetrazine.gif No colour change
Phenmetrazine Phenmetrazine.gif No colour change
Phentermine Fentermine.gif Orange - Brown Colour turns more Brown (± 3 min) Marquis phentermine dhp.png
PMA Pma.gif No colour change
Theobromine Theobromine.gif No colour change
TMA-2 Tma2.gif Light Green
TMA-6 Tma6.gif Yellow - Orange Colour turns Darker (± 3 min) Marquis tma6 dhp.png
Tramadol Tramadol.gif Orange - Brown Marquis tramadol DHP.jpg
Viagra Viagra.gif No colour change

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