Electrochemical profiling and liquid chromatography–mass spectrometry characterization of synthetic cathinones: From methodology to detection in forensic samples

Abstract

The emergence of new psychoactive drugs in the market demands rapid and accurate tools for the on‐site classification of illegal and legal compounds with similar structures. Herein, a novel method for the classification of synthetic cathinones (SCs) is presented based on their electrochemical profile. First, the electrochemical profile of five common SC (i.e., mephedrone, ethcathinone, methylone, butylone, and 4‐chloro‐alpha‐pyrrolidinovalerophenone) is collected to build calibration curves using square wave voltammetry on graphite screen‐printed electrodes (SPEs). Second, the elucidation of the oxidation pathways, obtained by liquid chromatography–high‐resolution mass spectrometry, allows the pairing of the oxidation products to the SC electrochemical profile, providing a selective and robust classification. Additionally, the effect of common adulterants and illicit drugs on the electrochemical profile of the SC is explored. Interestingly, a cathodic pretreatment of the SPE allows the selective detection of each SC in presence of electroactive adulterants. Finally, the electrochemical approach is validated with gas chromatography–mass spectrometry by analyzing 26 confiscated samples from seizures and illegal webshops. Overall, the electrochemical method exhibits a successful classification of SC including structural derivatives, a crucial attribute in an ever‐diversifying drug market.

Tetracycline Antibiotics: Elucidating the Electrochemical Fingerprint and Oxidation Pathway

“…Subsequently, N,N-dimethylcyclohexylamine (Figure S1h) was used in the experiment, because of its tertiary amine ionizable group, to verify the origin of the second peak. As can be seen in Figure 2 and Figure S2 (red dashed line), both EFs from the corresponding TC and the N,N-dimethylcyclohexylamine overlap at pHs above 8, since the tertiary amine is protonated bellow pH 7, making its oxidation difficult [68,76]. Last but not least, the origin of a third oxidation process at higher potentials and basic pHs could be associated with the oxidation of some hydroxyl groups present in the chemical structures of TCs.…”

Human Neuronal Cell Lines as An In Vitro Toxicological Tool for the Evaluation of Novel Psychoactive Substances

“…Additionally, the effects of cathinones and phenethylamines have been studied in vivo by using animal models [24,[45][46][47][48][49]. Moreover, high-resolution methods have been developed to detect these classes of NPS in different kinds of biological specimens (e.g., urine, hair, and plasma) [50,51].…”

Portable Electrochemical Detection of Illicit Drugs in Smuggled Samples: Towards More Secure Borders

“…In previous works, our research group has optimized the detection of illicit drugs by exploring certain conditions during the SWVs. For example, the anodic pretreatment to unravel the phenolic group oxidation of the 6-monoacetylmorphine (6-MAM) (a byproduct of heroin degradation at pH 12) [12], the cathodic pretreatment to avoid the suppressing effect of some adulterants [13] or the use of different pH (as some moieties are not oxidizable in certain pH at SPE) [11]. Besides, some illicit drugs such as amphetamine need a derivatization step to allow its electrochemical profiling employing low-cost carbon SPEs.…”

“…The electrochemical approach is based on the characteristic electrochemical profile (EP) of each compound that reveals the electroactive moieties of the target compound. Following this strategy, cocaine [10], ketamine [11], heroin [12] and synthetic cathinones [13] have been detected by using low-cost screen-printed electrodes (SPEs). Amphetamine is a special case as it is not electroactive in the potential window of commercial carbon SPEs.…”