Marquis reagent

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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. This is done by slowing down the polymerisation process.[citation needed]

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:

Results[edit]

Marquis reagent test analysis[2][3]
Substance Color Time (s) Notes
MDMA or MDA purple to black 0-5 may have dark purple tint
Amphetamine or Methamphetamine orange to brown 0-5 may have a brown tint
2C-B orange to green 5-10 color may change from initial result
DXM gray to black 15-30 initially no change; takes much longer to reach black than MDMA
Final colors produced by Marquis Reagent with various substances[1]:3–6[4]
Substance Color
2C-B - 4-bromo-2,5-dimethoxyphenethylamine Green-Yellow
2C-I - 2,5-dimethoxy-4-iodophenethylamine Green-Yellow
2,5-Dimethoxy-4-bromoamphetamine (DOB) Olive Green - Yellow
2-FMA Rapidly fizzes and dissolves. Colourless/Light yellow[citation needed]
25I-NBOMe Orange[citation needed]
25C-NBOMe Clear (No change)[citation needed]
25B-NBOMe Dark Green[citation needed]
5-EAPB Purple to Black[citation needed]
Aspirin Deep red
Adrafinil Deep reddish orange - Dark reddish brown[citation needed]
Benzphetamine HCl Deep reddish brown
BZP(BenzylPiperazine) Clear (fizzes)
Butylone Yellow[4]
Chlorpromazine HCl Deep purplish red
Codeine Very dark purple
Caffeine Clear (no change)
Cocaine Clear (No change)
d-Amphetamine HCl Strong reddish orange - Dark reddish brown
d-Methamphetamine HCl Deep reddish orange - Dark reddish brown
Diacetylmorphine HCl (Heroin) Deep purplish red
Dimethylamylamine (DMAA) No color change (fizzes)
Dimethyltryptamine (DMT) Orange
Dimethoxy-meth HCl Moderate olive
Doxepin HCl Blackish red
Dristan Dark grayish red
Exedrine Dark red
LSD Olive black
Methoxetamine Slow pink[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 HCl Deep brown
Mescaline HCl Strong orange
Methadone HCl Light yellowish pink
Methylphenidate HCl Moderate orange yellow
Methylene Blue Dark Green
Modafinil Yellow/Orange --> Brown[5]
Morphine monohydrate deep purplish red
Opium Dark grayish reddish Brown
Oxycodone HCl Pale violet
Propoxyphene HCl Blackish purple
Sugar Dark brown

Mechanism[edit]

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 oxoniumcarbenium salt.[6]

See also[edit]

References[edit]

  1. ^ a b "Color Test Reagents/Kits for Preliminary Identification of Drugs of Abuse" (PDF). Law Enforcement and Corrections Standards and Testing Program. July 2000. Retrieved 2011-07-24. 
  2. ^ "Marquis Reagent Testing Kit (White Label)". Testing Kits. DanceSafe. Retrieved 2011-07-22. 
  3. ^ "Adulterant Screening Kit Instructions". DanceSafe. Retrieved 2011-07-24. 
  4. ^ a b c Morris, Jeremiah. "Color Tests and Analytical Difficulties with Emerging Drugs". Johnson County Sheriff’s Office Criminalistics Laboratory: NIST. p. 36. Retrieved 10 May 2014. 
  5. ^ Morris, Jeremiah (2004). "Analytical Profile of Modafinil" (PDF). Microgram Journal 3 (1-2): 28. Retrieved 2013-10-09. 
  6. ^ Lancashire, Robert J. (2011-10-13). "Unit 9: Crime - Reagent Kits". University of the West Indies, Mona Campus. Retrieved 2014-03-17. 

External links[edit]