What is Reagent Testing?
Reagent testing involves a chemical reaction to determine if a certain substance is present in a sample. Reagents typically indicate the presence of compounds by triggering changes in colors to indicate the presence or absence of a substance. When it comes to reagent testing for drugs a small sample of the substance in question is usually placed on a test strip or platform then a small amount of the reagent chemical is added. The reagent will cause the sample area to turn a different color, then using a color code it can be determined if certain drugs are present. Some tests can be dropped directly onto the substance itself, but most are tested using a small sample, requiring a scraping or cut of the drug on which a droplet of the reagent is placed.
A reagent test allows users to match the colored result with a key that tells what certain colors mean in determining whether a particular drug is present or not. One of the best methods for making a firm call on the identity of a substance is to test it with multiple different reagents. Reagent tests don’t test for purity, but rather detect the presence of substances in a drug.
Here’s a video, courtesy of DanceSafe, that demonstrates the process of reagent testing using different kinds of tests:
Five of the Most Common Reagent Tests
- Ehrlich’s: Ehrlich’s reagent is a test that contains a chemical called DMAB that can detect indoles and urobilinogen. Spot tests can be used to identify tryptamines and ergoloids, like DMT and LSD. This reagent has usefulness in identifying certain diseases as well.
- Liebermann: Liebermann reagent is used for spot tests in identifying alkaloids and other compounds. Composed of sulfuric acid and potassium nitrate, Liebermann reagent helps determine if a substance contains cocaine, morphine, PMA, or PMMA.
- Mecke: Mecke reagent contains sulfuric acid and selenous acid and is used to identify alkaloids and more.
- Mandelin: Composed of ammonium metavanadate and sulfuric acid, Mandelin reagent can be used in identifying alkaloids, much like the other reagent tests. This test does well in identifying ketamine and PMA specifically.
- Marquis: Marquis reagent is made of formaldehyde and sulfuric acid. This test is best used to identify amphetamines, ecstasy, and phenethylamines. The color change that this reagent goes through is also important in identifying the presence of drugs in what’s being tested. To accurately get results, sometimes the test can take up to 30 minutes, particularly when getting a DXM result.
A reagent test color chart, courtesy of DanceSafe:
The Importance of Reagent Testing
Reagent testing can be used as part of harm reduction, by helping those who use drugs non-medically ensure they’re not taking something adulterated (like a pill laced with fentanyl, for example). Psychonaut Wiki, a drug database that operates under harm reduction principles to help spread knowledge of substances used non-medically, has a list of steps on how to use a reagent test properly:
- Scrape a tiny bit of your pill or powder (or cut a tiny piece, if handling a blotter) onto a large, white ceramic plate. Use just enough powder to see on the plate.
- Take the reagent bottle out of the plastic safety container. Remove the cap and turn the bottle upside-down a couple inches over the powder.
- Squeeze one drop out of the bottle onto the powder. Be careful to not let the dropper bottle touch your powder or you will contaminate and ruin the rest of the reagent. Replace the cap.
- Observe the color change right away. Optionally you can film the reaction with your phone or a camera for future reference. Use the corresponding columns of the color chart included with your kit to evaluate your test.
- If the reagent either does not change any color during the first 30 seconds or if it produces some other color-change sequence, then the pill definitely does not contain any of the above substances. It may also be highly adulterated with one or more unknown substances. You can use other reagents on new samples to look for the presence of other substances. Wash the testing surfaces with soap and water as soon as possible.
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