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. Different compounds produce different color reactions. Also, sometimes methanol is added to slow down the reaction process to observe the change in color better. Methanol does this by slowing down the polymerisation process.
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. methamphetamine, amphetamine).
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:
| 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 |
| 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 |
| 25I-NBOMe | Orange |
| 25C-NBOMe | Clear (No change) |
| Aspirin | Deep red |
| Benzphetamine HCl | Deep reddish brown |
| Chlorpromazine HCl | Deep purplish red |
| Codeine | Very dark purple |
| d-Amphetamine HCl | Strong reddish orange - Dark reddish brown |
| d-Methamphetamine HCl | Deep reddish orange - Dark reddish brown |
| Diacetylmorphine HCl (Heroin) | Deep purplish red |
| Dimethyltryptamine (DMT) | Orange |
| Dimethoxy-meth HCl | Moderate olive |
| Doxepin HCl | Blackish red |
| Dristan | Dark grayish red |
| Exedrine | Dark red |
| LSD | Olive black |
| Methylenedioxyamphetamine HCl (MDA) | Black |
| Methylenedioxy-N-ethylamphetamine HCl (MDEA) | Black |
| Methylenedioxymethamphetamine HCl (MDMA) | 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 |
| Morphine monohydrate | deep purplish red |
| Opium | Dark grayish reddish Brown |
| Oxycodone HCl | Pale violet |
| Propoxyphene HCl | Blackish purple |
| Sugar | Dark brown |
Famous quotes containing the word marquis:
“The art of newspaper paragraphing is to stroke a platitude until it purrs like an epigram.”
—Don Marquis (1878–1937)