Marquis reagent is used as a simple spot-test to presumptively identify

alkaloids Alkaloids are a broad class of naturally occurring organic compounds that contain at least one nitrogen atom. Some synthetic compounds of similar structure may also be termed alkaloids. Alkaloids are produced by a large variety of organisms i ...

as well as other compounds. It is composed of a mixture of

formaldehyde Formaldehyde ( , ) (systematic name methanal) is an organic compound with the chemical formula and structure , more precisely . The compound is a pungent, colourless gas that polymerises spontaneously into paraformaldehyde. It is stored as ...

and concentrated

sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid (English in the Commonwealth of Nations, Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen, ...

, which is dripped onto the substance being tested. The

United States Department of Justice The United States Department of Justice (DOJ), also known as the Justice Department, is a United States federal executive departments, federal executive department of the U.S. government that oversees the domestic enforcement of Law of the Unite ...

method for producing the reagent is the addition of 100 mL of concentrated (95–98%) sulfuric acid to 5 mL of 40% formaldehyde. Different compounds produce different color reactions.

Methanol Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical compound and the simplest aliphatic Alcohol (chemistry), alcohol, with the chemical formula (a methyl group linked to a hydroxyl group, often ab ...

may be added to slow down the reaction process to allow better observation of the colour change.

History

Marquis reagent was first discovered in 1896Toxicology. Volume 2 : mechanisms and analytical methods
— New York, New York; San Francisco, California : Academic Press, 1961 — p. 247. and described by the Russian (Estonian) pharmacologist, Eduard Markus (1871–1944) () in his magister dissertation in 1896; and named after him, and was tested for the first time at the University of Dorpat. The reagent should be stored in the freezer for maximum shelf life. Marquis Reagent

It is the primary presumptive test used in Ecstasy

reagent testing Reagent testing is one of the processes used to identify substances contained within a pill, usually illicit substances. With the increased prevalence of drugs being available in their pure forms, the terms "drug checking" or "pill testing" may a ...

kits. It can also be used to test for such substances as

opiate An opiate is an alkaloid substance derived from opium (or poppy straw). It differs from the similar term ''opioid'' in that the latter is used to designate all substances, both natural and synthetic, that bind to opioid receptors in the brain ( ...

s (e.g.

codeine Codeine is an opiate and prodrug of morphine mainly used to treat pain, coughing, and diarrhea. It is also commonly used as a recreational drug. It is found naturally in the sap of the opium poppy, ''Papaver somniferum''. It is typically use ...

heroin Heroin, also known as diacetylmorphine and diamorphine among other names, is a morphinan opioid substance synthesized from the Opium, dried latex of the Papaver somniferum, opium poppy; it is mainly used as a recreational drug for its eupho ...

), and

phenethylamine Phenethylamine (PEA) is an organic compound, natural monoamine alkaloid, and trace amine, which acts as a central nervous system stimulant in humans. In the brain, phenethylamine regulates monoamine neurotransmission by binding to trace ami ...

s (e.g. 2C-B,

mescaline Mescaline, also known as mescalin or mezcalin, and in chemical terms 3,4,5-trimethoxyphenethylamine, is a natural product, naturally occurring psychedelic drug, psychedelic alkaloid, protoalkaloid of the substituted phenethylamine class, found ...

). 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:

Results

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.

Mechanism

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.

References

{{Reflist

External links

Marquis reagent colors list, very comprehensiveMarquis Reagent Testing Kit - WIM Scientific LaboratoriesDHPedia - Marquis reagent: A comprehensive list of colour reactions
Chemical tests Analytical reagents Drug testing reagents Formaldehyde

History

Results

Mechanism

See also

References

External links