Portable 3D-printed system for on-site MDMA electrochemical detection.

MDMA (3,4-methylenedioxymethamphetamine), also known as "ecstasy", is a widely used stimulant and hallucinogenic drug. Its popularity in recreational settings is attributed to its euphoric effects; however, MDMA consumption is associated with health risks. The global increase in synthetic drug consumption highlights the urgent need for rapid, cost-effective, and portable detection systems for on-site analysis. In this study, a simple, sensitive, and portable 3D-printed electrochemical system was developed for on-site quantitative and qualitative detection of MDMA. The electrode surface was first sanded to partially remove the insulating polylactic acid (PLA) layer and subsequently irradiated with a CO2 laser to expose conductive carbon regions. Morphological characterizations confirmed surface modification, while electrochemical studies revealed a significant improvement in electrochemical performance after treatment. The reagent-free treatment enabled sensitive MDMA detection using differential pulse voltammetry (DPV), with a linear response in the concentration range of 2.5 to 100 μmol L-1 MDMA and limits of detection (LOD) and quantification (LOQ) of 0.080 and 0.27 μmol L-1 MDMA, respectively. The electrodes exhibited good reproducibility (RSD = 5.50%, n = 5) and stability, with only a 13% decrease in peak current after 28 days of storage. The sensor was also successfully applied to detect MDMA in seized tablet samples. With minimal sample consumption (100 μL), low waste generation, and a low production cost (≈US$0.18 per device), the system supports a one-sensor-per-analysis approach that can be easily operated by a non-electrochemist analyst. Compact and smartphone-compatible, the device represents a promising, low-cost, on-site-deployable alternative for rapid MDMA screening in forensic and law enforcement applications.