A two-step electrochemical sensor distinguishes between the drugs MDMA and 2C-B. In the first step, direct electrochemical analysis detects MDMA, but testing over 70 substances showed that 2C-B was the only common drug producing a false positive for MDMA. The second step uses formaldehyde to chemically modify 2C-B, creating a distinct electrochemical signal that differentiates it from MDMA. Testing on 71 ecstasy tablets seized by the Amsterdam Police, the sensor correctly identified all 39 MDMA-containing tablets and 10 of 11 tablets containing 2C-B. It also worked on dark-colored tablets where spectroscopic and colorimetric tests failed.
Four portable analytical methods for drug checking at events were compared using MDMA samples. Mid-infrared (MIR) spectroscopy and an electrochemical sensor approach performed best. The electrochemical method directly measured the percentage of MDMA in samples, while MIR could screen for multiple substances and identify unexpected active components, an advantage given the rise of new psychoactive substances. Near-infrared and Raman spectroscopy were the other two methods tested. The study demonstrates that practical, easy-to-use approaches exist for harm reduction at events, though each method has trade-offs between specificity and breadth of detection.