Mecke Reagent: What It Detects, Color Chart and How to Use It With Marquis
Mecke is the standard second reagent after Marquis: green-to-blue for MDMA, green for heroin, and a clear way to tell opioids apart. Full colour chart, timing, and the two-reagent protocol.
The short answer: Mecke turns green → dark blue/black with MDMA and green with heroin and morphine, which makes it the standard confirmation reagent alongside Marquis. Marquis tells you "probably MDMA"; Mecke is what separates MDMA from the impostors (PMA, cathinones, amphetamine) and what distinguishes heroin from fentanyl — where the colour is often weak or absent, which is itself the warning sign.
| Mecke colour | Likely substance | What it means for you |
|---|---|---|
| Green → dark blue/black | MDMA / MDA | Confirms a Marquis purple reaction — strong pair |
| Green → blue-green | Heroin, morphine, codeine | Opioid class present; use [fentanyl strips](/kits/fentanyl-strips) regardless |
| Green → dark green | Oxycodone | Differentiate from heroin |
| Brown / dark brown | DXM | Common in "fake" pills |
| Little or no colour | Possibly fentanyl or a substance Mecke misses | Never read as safe — strips are the only fentanyl check |
The two-reagent rule: Marquis first for a broad read, Mecke second to confirm. A single reagent is a clue; two agreeing reagents is evidence. Mecke is also the reagent that tells you when your MDMA is actually a cathinone or PMA — the substitutions that hospitalise people.
→ Mecke Reagent Kit ($25) · Marquis Reagent Kit · Marquis vs Mecke vs Froehde · Full reagent chart
What Is Mecke Reagent?
Mecke reagent is a selenious acid-based testing solution that produces distinctive color reactions with a range of psychoactive substances. It is most commonly used as a confirmatory reagent alongside Marquis, the two together provide a much more complete picture than either alone.
Chemical composition: Selenious acid (H₂SeO₃) in concentrated sulfuric acid (H₂SO₄)
Why it is important: Marquis is the best screening reagent, but it produces similar colors for different substances (MDMA and heroin both turn purple/black with Marquis). Mecke produces different colors for different substances, allowing you to distinguish between compounds that Marquis cannot tell apart.
Mecke Color Guide
| Substance | Mecke Reaction | Distinguished From |
|---|---|---|
| MDMA | Green → Dark Blue / Black | Confirms MDMA after Marquis (Marquis turns purple for both MDMA and heroin, Mecke tells them apart) |
| Heroin | Green → Blue-Green | Heroin turns blue-green with Mecke, NOT dark blue/black like MDMA |
| Morphine | Blue-Green | Similar to heroin, Mecke alone cannot distinguish them |
| Codeine | Blue-Green | Same as morphine/heroin class |
| Oxycodone | Green → Dark Green | Distinct from other opioids, a useful signal |
| Cocaine | No reaction / pale yellow | Same as Marquis, no reaction is actually expected |
| Amphetamine | No reaction / pale yellow | Mecke does not detect amphetamines, use Marquis + Simon's |
| LSD | No reaction | Use Ehrlich instead |
| DMT | Yellow → Green → Brown | Distinctive progression, confirms tryptamine after Ehrlich |
| 2C-B | Yellow / Brown | Different from Marquis (yellow/green), useful secondary confirmation |
| PMA / PMMA | No reaction | Same as Marquis, if neither reagent reacts on suspected MDMA, you may have PMA |
| DXM | Brown / Dark Brown | Distinct from other opioids and dissociatives |
| Ketamine | No reaction | Use Morris + Mandelin |
Marquis vs Mecke: When to Use Which
| Scenario | Use Marquis | Use Mecke | Why |
|---|---|---|---|
| Screening unknown white powder | ✅ First | ❌ | Marquis reacts with more substances, better initial test |
| Confirming MDMA | ✅ First | ✅ Second | Marquis turns purple (fast), Mecke turns green/blue (confirms not heroin) |
| Distinguishing MDMA from heroin | ❌ | ✅ | Both turn purple with Marquis. Mecke separates them |
| Testing opioids | ✅ Screening | ✅ Identification | Marquis screens, Mecke identifies specific class |
| Testing cocaine | ✅ (non-reaction) | ❌ | Marquis non-reaction is useful. Mecke adds nothing |
| Testing 2C-B | ✅ (yellow/green) | ✅ (yellow/brown) | Both work, two points of confirmation |
The Three-Reagent MDMA Protocol
For definitive MDMA identification, use three reagents in sequence:
- Marquis, Must turn purple/black (if not, it is NOT MDMA, PMA warning)
- Mecke, Must turn green then dark blue/black (confirms MDMA, rules out heroin)
- Simon's, Must turn bright blue (confirms MDMA, rules out MDA)
If any of these three reactions is unexpected or missing, your sample is not pure MDMA.
Protect your connection while traveling
Mecke Reagent Shelf Life
| Condition | Duration |
|---|---|
| Unopened, refrigerated | 12-18 months |
| Opened, refrigerated | 8-12 months |
| Opened, room temperature | 6-12 months |
| Degradation signs | Fading to yellow, slower reaction times |
Mecke is somewhat less stable than Marquis or Ehrlich. Check the color of the liquid, fresh Mecke is pale yellow. If it has turned dark yellow or brown, replace it.
Where to Buy
Mecke Reagent, $25.00 CAD (individual bottle)
Pro 6-in-1 Kit, $108.00 CAD (includes Marquis, Simon's, Mecke, Froehde, Morris, Ehrlich)
Complete 9-in-1 Kit, $150.00 CAD (full lab)
Disclosure: Affiliate links. We may earn a commission at no extra cost to you.
Kits Mentioned in This Article
Fentanyl Test Strips 10-Pack — Detects Below 200 ng
Fentanyl test strips with a detection limit below 200 ng and over 98% accuracy. Tests powders, pills, and liquids. 10 strips with instructions included.
Mecke Reagent Test Kit
An essential reagent for verifying MDMA and identifying dangerous adulterants like PMA/PMMA.
Marquis Reagent Test Kit — Detects MDMA, Meth, Speed & Opiates
The #1 drug checking reagent. Identifies MDMA, amphetamine, methamphetamine, and opiates in 30 seconds. Includes color chart card, testing surface, and instructions.
Ready to Test Safely?
All reagents, test strips, and testing accessories mentioned in this guide are available in our catalog — shipped discreetly worldwide.