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Why the Marquis Reagent is a Must Have

Posted by Mad Scientist on

Marquis reagent test

Why Marquis?

Reagents are specific to the type of substances they can analyze; however, some reagents are capable of identifying as well as rule out more than one drug in a sample. Marquis reagent is versatile as it can be used to test a wide variety of drugs.

If you were to own only one drug test, then Marquis reagent should be the one.

Formula for the Marquis Reagent

Marquis reagent is made by combining a formula of concentrated sulfuric acid and formaldehyde. The United States Department of Justice recommends preparing the reagent by adding 100 ml of concentrated (95–98%) sulfuric acid to 5 mL of 40% formaldehyde.

Because this is a preparation of concentrated acid, it's important to handle it with care. The Marquis reagent is colourless in nature, and lasts about a year. It's best to store this reagent refrigerated to prolong shelf life. However, this reagent does turn darker with time, although it would still work and react with the substance being tested on.

What Substances can Marquis Reagent Test

Following are some of the most common drugs/substances the Marquis reagent can identify in a sample:

  • MDMA
  • MDA
  • MDE
  • 5-MAPB
  • 6-APB
  • Amphetamine
  • Methamphetamine
  • 2-FMA
  • 2C-B
  • 2C-I
  • 2C-H
  • Cathinones
  • 2C-B-FLY
  • 2-FA
  • Heroin
  • Codeine
  • Morphine
  • 6-APDB
  • 4-FMA
  • BZP
  • Cocaine
  • Ketamine
  • MDAI
  • 3-FA
  • 4-FA
  • Ephedrine
  • Levamisole
  • DMT
  • 5-MeO-DMT
  • DOI
  • DOM
  • DOC
  • NBOMe
  • 1P-LSD
  • ALD-52
  • Harmine
  • Harmaline
  • 3-MMC
  • MDPV
  • 4-FMC
  • 4-MMC
  • 2-MMC
  • Oxycodone
  • DXM

Marquis reagent and its common test reactions

Marquis reacts with a colour change with different substances indicative of the substance type. Let's take a look at some of the common reactions of the Marquis reagent with different drugs.

Marquis Colour Reaction Chart

Marquis colour reaction chart

Marquis and MDMA

MDMA and similar substances such as MDE, MDA, MDPV, 5-MAPB and 5-ABP all react with a distinct purple to a quick black colour change.

Marquis and Amphetamine/Methamphetamine

With Meth and Amphetamine, the Marquis reagent reacts with a light orange to a deep orange colour reaction.

Marquis and 2C-B

With 2C-B, Marquis reagent reacts with a yellow to green colour change.

Marquis and Cocaine

With cocaine, there is no colour reaction with Marquis.

Marquis and Ketamine


With Ketamine, there is no colour reaction with Marquis.

Marquis and DMT/Harmine/Harmaline

Marquis reacts with a light to dark peach with DMT, Harmine and Harmaline.

Marquis and Opioids


With Heroin, Morphine and Codeine, the Marquis reagent reacts with a light to dark purple colour change.

Marquis and 1P-LSD/ALD-52

With these drugs Marquis reagent reacts with a light to darker pink colour change.

Marquis and NBOMe

With this dangerous substance, Marquis reacts with a bright colour change such as bright green, yellow, orange or pink.

Marquis and 4-FMA

Marquis reagent reacts with a light to darker shade of pink with 4-FMA.

Marquis as the Primary Reagent

Reagents can be of two types depending on the type of substance being tested - primary or secondary. Primary tests are used to identify the expected substance and secondary tests are used to rule out adulterants.

For example, with Cocaine, Liebermann would be the primary reagent as it helps to positively identify cocaine and Marquis reagent would be secondary as it can rule out the adulterant Levamisole.

Marquis is a primary reagent for the following
  • MDMA
  • 2C-B
  • Heroin
  • Morphine
  • Codeine
  • Methamphetamine
  • Amphetamine
  • MDA/5-MAPB/6-APB
  • 4-FMA
  • 2-FA
  • Cathinones
Marquis is a secondary reagent for the following
  • LSD
  • DMT
  • Cocaine

How to best use the Marquis Reagent

Marquis is a quick reacting reagent, which responds fairly quickly to most tested powders, as compared to some slower reacting reagents such as Hofmann, which can take up to 30 minutes.

  • Prepare your sample, of a very small size, the size of a matchstick head and place it on a spot testing plate or any other ceramic surface like the back of a mug.
  • Add one drop of the reagent to the sample.
  • Record and observe the reaction for later reference.
  • Use Marquis reagent first where it's a primary reagent.
  • Use Marquis as a follow up reagent where it's a secondary reagent
  • Fizzing of the substance is normal.
  • A faster reaction is not indicative of a higher drug purity.
  • Don't allow the reagent to come in contact with the skin, and if it does, wash thoroughly with soap and water.
  • Once testing is complete, was the surface thoroughly under running water.

Marquis reagent demo video

What should you do if Marquis doesn't react?


As with all tests and reagents, if the test doesn't react or reacts unexpectedly, it's best to follow up with additional reagents.

As a general practice it's always good to use more than one reagent while testing for substances, as it improves accuracy.

Now you know why every substance tester should get the Marquis Reagent!

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