Rapid screening of synthetic cathinones as trace residues and in authentic seizures using a portable mass spectrometer equipped with desorption electrospray ionization

Rationale: Recently, the surge in synthetic cathinone abuse has become a matter of public concern. With the influx of confiscated synthetic cathinones dramatically on the rise, laboratory workloads are expected to increase at a similar rate. This prompts the need for rapid analytical methods capable of detecting and identifying such compounds.

Methods: A ruggedized, portable ion trap mass spectrometer capable of desorption electrospray ionization mass spectrometry (DESI-MS) was used to rapidly characterize various synthetic cathinones. Target analytes were directly analyzed as trace residues on various substrates and as major components in authentic, powder-based forensic evidence. Physical transfer swabs can also be examined with this method, allowing efficient screening of large areas and geometrically complex samples.

Results: Method validity was tested on trace residues, mock forensic samples, and authentic evidentiary seizures, yielding low- to sub-ng detection limits from several substrates of interest to crime scene investigation. Analyte confirmation was accomplished through MS(2) analysis, providing characteristic fragmentation similar to that reported in literature. High-throughput analysis was demonstrated with no significant instrumental carryover, even for powdered samples. The robustness of this DESI-MS method to multi-component samples was examined, marked by high chemical specificity.

Conclusions: Coupling DESI-MS with portable instrumentation allowed sensitive and selective examination of synthetic cathinones from various substrates, in complex mixtures, and directly from mock and authentic forensic evidence. This instrumental method has the potential to assess the evidentiary value of forensic samples at crime scenes, reducing backlogs and expediting criminal investigations.