Developing electrodes chemically modified with cucurbit[6]uril to detect 3,4-methylenedioxymethamphetamine (MDMA) by voltammetry

• A new stand in forensic chemistry.
• Voltammetric method for the determination of MDMA in seized samples.
• A new voltammetric sensor for MDMA.

This study aimed to develop an electrode chemically modified with cucurbit[6]uril to detect 3,4-methylenedioxymethamphetamine (MDMA), the main active principle of ecstasy samples, by voltammetry.We modified the electrode surface with a film containing cucurbit[6]uril, Nafion, and methanol, using the dip coating or the spin coating technique. During analysis, we employed an electrochemical cell with a conventional three-electrode system and KCl solution (0.1 mol L−1) as the supporting electrolyte. We conducted cyclic voltammetry at concentrations ranging from 4.2 × 10−6 to 4.8 × 10−5mol L−1. We also accomplished scanning electron microscopy, to investigate the structural behavior of the film that originated on the electrode surface.We obtained the following results when we used dip coating to prepare the modified electrode: standard deviation (SD) = 0.024 μA, limit of detection (LOD) = 3.5 μmol L−1, limit of quantification (LOQ) = 11.7 μmol L−1, and amperometric sensitivity (m) = 20.9 × 103 μA L mol−1. As for spin coating, we obtained SD = 0.024 μA, LOD = 2.7 μmol L−1, LOQ = 9.1 μmol L−1 and m = 25.9 × 103 μA mol L−1. These are very promising data: the modified electrode is more sensitive than the conventional glassy carbon electrode under the studied experimental conditions.

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