Marquis Reagent Testing Kit – An Overview

Marquis Reagent is a substance that is used to spot test and identify alkaloids and other compounds present in a composition. It mainly comprises a mixture of concentrated sulphuric acid and formaldehyde. This mixture is dripped onto another substrate being tested.

According to the United States Department of Justice, the right way to produce Marquis Reagent is to add 100ml of concentrated sulphuric acid and 5ml of 40% formaldehyde. When added to the substrate, different compounds produce different color changes depending on the agents found in them—for example, the color changes when methanol is added to the reaction. Hence the exact readings can be noted down.

The discovery of the resident Eduard Marquis in 1896 stated that the reagent should be stored carefully in a freezer to maintain its maximum shelf life.

Marquis Reagent Testing Kit

One of the primary uses of these kits is to test the presence of ecstasy and MDMA in certain drugs and compounds. However, it can also be used to test the presence of substances like codeine, heroin, and phenethylamines in certain compounds.

The test is primarily performed by scraping a small amount of substance under the test and adding drops of Marquis Reagent. The reagent is initially colorless, transparent, and odorless. However, a substantial color change is observed in addition to the substance, which is viewed and analyzed based on the compound found in the substance under test.

The reagents’ test results can take place in a matter of seconds due to their reaction with air and moisture.

Results from Marquis Reagent Testing Kit

  • In the presence of MDMA or MDA, the color changes from purple to black within 5 seconds and might have a dark purple tint around it.
  • In the presence of amphetamine or methamphetamine, the color changes from orange to brown within the first 5 seconds and might also have a brown tint around it.
  • In the presence of 2C-B, the color changes from yellow to green within 5 to 10 seconds.
  • In the presence of DXM, the color changes from grey to black for 15 to 30 seconds. It also takes much more time to reach the final black color when compared to MDMA.
  • Mechanism of color change

Marquis Reagent

Although the working mechanism of the Marquis Reagent Testing Kit is not fully understood, the process is believed to succeed due to the presence of stable carbon atoms, which undergo a process called carbonation. The reaction of Marquis Reagent to certain substances like morphine involves dimerization with two different molecules, which forms an oxonium ion, which is majorly responsible for the apparent color change. One of the most significant tests to check for the working of this reagent after its preparation is by bringing it in contact with sugar, which turns brown in the presence of Marquis Reagent.


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