Presumptive analysis of 4-methylmethcathinone (mephedrone) using Desorption Electrospray Ionisation - Mass Spectrometry (DESI-MS)

Abstract

4-Methylmethcathione (4-MMC or mephedrone) is a prevalent drug of abuse globally. 4-MMC is often marketed as 'bath salts' and is readily available over the internet. The need for a rapid universal technique capable of detecting an extensive range of drug compounds has become increasingly important with the continued emergence of novel drug analogues. Desorption electrospray ionisation -mass spectrometry (DESI-MS) is a mass spectrometry technique that allows for the analysis of compounds directly from ambient surfaces, reducing or eliminating the need for sample preparation. Although 4-MMC has gained significant attention in recent years, the application of the DESI-MS technique to the fast presumptive detection and chemical analysis of this analogue has not been presented. In the present study, DESI-MS was applied to the rapid qualitative analysis of 4-MMC. A particularly suitable surface, semi-porous polytetrafluoroethylene (PTFE, Teflon) was utilised, as it generated the least variable signal and reproducibility compared to other surfaces (polymethyl-methacrylate (PMMA) and polyvinyl chloride (PVC)). Selectivity of the technique to the detection of 4-MMC was evaluated by analysing a range of adulterated samples including mixtures containing caffeine, methylamphetamine, cathinone and paracetamol. Specificity based on tandem MS (MS/MS) was also demonstrated by analysing substances with the same molecular formula as 4-MMC. Accuracy (% RE) and precision (% RSD) of the method were found to be within 13% and 38%, respectively; and therefore the quantitative data provided by the DESI-MS method is limited compared to gas chromatography-mass spectrometry (GC-MS; accuracy < 13% and precision < 12%). The results suggest that DESI-MS can greatly aid in the rapid presumptive identification of 4-MMC and other similar novel drug analogues.

Qualitative analysis of seized cocaine samples using desorption electrospray ionization‐ mass spectrometry (DESI‐MS)

“…[9,10] Due to the difficulty in analysing powder substances, cocaine samples were dissolved in solvent which was much more convenient than making solid disk out of the cocaine powder before DESI-MS analysis. The large range of compounds (varying in structural size and functional groups) meant that the technique needed to be optimized to enable broad detectability.…”

“…Previous studies have demonstrated the ability of the technique to analyse samples directly from solid surfaces, however, due to the variable forms in which illicit drug seizures are encountered it was important to develop a technique capable of analysing both solid and other forms such as liquid in a timely manner. [9,10] Due to the difficulty in analysing powder substances, cocaine samples were dissolved in solvent which was much more convenient than making solid disk out of the cocaine powder before DESI-MS analysis. Table 1).…”

“…[7,8] DESI-MS has the ability to detect drug samples in the ambient environment with little sample preparation and high-throughput. This technique has gained popularity due to its broad applicability including illicit drugs, [7][8][9][10] steroids, [11] chemical warfare agents, [12] inks/ documents, [12] fingermarks, [12] gunshot residues, [13] drugs in urine and plasma, [14] and explosives. [15] Using this technique, ions can be generated directly from solid surfaces of various types.…”

Isolation and structural determination of non-racemic tertiary cathinone derivatives

“…[12][13][14][15] Several new techniques are now being applied to both rapidly screen seized samples, [16][17][18][19] and to identify metabolized products. [12][13][14][15] Several new techniques are now being applied to both rapidly screen seized samples, [16][17][18][19] and to identify metabolized products.…”

Current applications of high-resolution mass spectrometry for the analysis of new psychoactive substances: a critical review

“…In addition, the use of matrix-assisted laser desorption ionization (MALDI) and desorption electrospray ionization (DESI) coupled to HRMS has been reported for the analysis of NPS [52][53][54]. Ostermann et al [52] analyzed NPS CRMs and authentic samples using MALDI coupled to an LTQ-Orbitrap.…”