Synthetic Cathinones'\nComprehensive Screening and\nClassification by Voltammetric and Chemometric Analyses: A Powerful\nMethod for On-Site Forensic Applications

The use of synthetic cathinones (SCs) has increased in\nrecent years,\nposing significant public health problems due to their adverse effects\nand potential for fatal poisonings. The structural diversity and rapid\nemergence of new SC analogues create challenges for law enforcement\nand drug screening techniques. This work presents for the first time\nthe electrochemical detection of SCs using differential pulse voltammetry\n(DPV) on a boron-doped diamond electrode (BDDE). We analyzed 15 SCs,\nincluding well-known compounds such as mephedrone, methylone, and\nephylone, revealing distinct electrochemical profiles with two characteristic\nreduction peaks (R<sub>1</sub> and R<sub>2</sub>). The method was\noptimized in Britton–Robinson buffer (0.1 mol L<sup>–1</sup>, pH 8.0) and demonstrated a high selectivity and sensitivity. Multivariate\nstatistical methods, including principal component analysis and hierarchical\ncluster analysis, classified SCs into six distinct groups. The DPV\noptimization and analytical parameter determination, including the\nlimit of detection (LOD), were performed for the least electroactive\nSC, 4′-methyl-α-pyrrolidinohexanophenone, yielding an\nLOD of 3.8 μmol L<sup>–1</sup>, suitable for screening\nstreet samples. Interference studies with common illicit drugs and\nadulterants confirmed the selectivity of the DPV-BDDE method. Preliminary\nidentification of SCs in 46 real seized samples was successfully performed\nusing this method with results validated by liquid chromatography–mass\nspectrometry (LC–MS). The\nmethod also identified three SCs not included in the original set:\nbupropion, benzylone, and dipentylone. The DPV-BDDE method offers\na rapid, robust, and portable approach for the selective screening\nof SCs in forensic applications, demonstrating significant advantages\nover traditional colorimetric tests.