title: Forensic electrochemistry: the electroanalytical sensing of synthetic cathinone-derivatives and their accompanying adulterants in "legal high" products.
abstract: The production and abuse of new psychoactive substances, known as "legal highs" which mimic traditional drugs of abuse is becoming a global epidemic. Traditional analytical methodologies exist which can provide confirmatory analysis but there is a requirement for an on-the-spot analytical screening tool that could be used to determine whether a substance, or sample matrix contains such legal, or formally "legal highs". In this paper the electrochemical sensing of (±)-methcathinone and related compounds at a range of commercially available electrode substrates is explored. We demonstrate for the first time that this class of "legal highs" are electrochemically active providing a novel sensing protocol based upon their electrochemical oxidation. Screen-printed graphite sensing platforms are favoured due to their proven ability to be mass-produced providing large numbers of reliable and reproducible electrode sensing platforms that preclude the requirement of surface pre-treatment such as mechanical polishing as is the case in the use of solid/re-usable electrode substrates. Additionally they hold potential to be used on-site potentially being the basis of an on-site legal high screening device. Consequently the electroanalytical sensing of (±)-methcathinone (3a), (±)-4′-methylmethcathinone [3b, 4-MMC, (±)-mephedrone] and (±)-4′-methyl-N-ethylcathinone (3c, 4-MEC) is explored using screen-printed sensing platforms with the effect of pH explored upon the analytical response with their analytical efficiency evaluated towards the target legal highs. Interesting at pH values below 6 the voltammetric response quantitatively changes from that of an electrochemically irreversible response to that of a quasi-reversible signature which can be used analytically. It is demonstrated for the first time that the electroanalytical sensing of (±)-methcathinone (3a), (±)-mephedrone (3b) and 4-MEC (3c) are possible with accessible linear ranges found to correspond to 16–200 μg mL(−1) for 3a (at pH 12) and 16–350 μg mL(−1) for both 3b and 3c in pH 2, with limits of detection (3σ) found to correspond to 44.5, 39.8 and 84.2 μg mL(−1) respectively. Additionally adulterants that are commonly incorporated into cathinone legal highs are electrochemically explored at both pH 2 and 12.
authors.affiliation: Faculty of Science and Engineering, School of Chemistry and the Environment, Division of Chemistry and Environmental Science, Manchester Metropolitan University, Chester Street, Manchester M1 5GD, Lancs, UK. c.banks@mmu.ac.uk.
authors.forename: Jamie P
authors.initials: JP
authors.lastname: Smith
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Metters
authors.forename: Craig
authors.initials: C
authors.lastname: Irving
authors.forename: Oliver B
authors.initials: OB
authors.lastname: Sutcliffe
authors.forename: Craig E
authors.initials: CE
authors.lastname: Banks
mesh_terms: D000470:Alkaloids / Q000032:analysis* / Q000737:chemistry*; D058110:Counterfeit Drugs / Q000032:analysis* / Q000737:chemistry*; D004563:Electrochemistry / Q000295:instrumentation*; D004566:Electrodes; D044707:Forensic Sciences / Q000379:methods*; D006108:Graphite / Q000737:chemistry; D011619:Psychotropic Drugs / Q000032:analysis / Q000737:chemistry
chemical_list: D000470:Alkaloids; D058110:Counterfeit Drugs; D011619:Psychotropic Drugs; C023665:cathinone; D006108:Graphite