Determination of synthetic and natural cannabinoids in oral fluid by solid-phase microextraction coupled to gas chromatography/mass spectrometry: A pilot study.

In 2008, several synthetic cannabinoids were detected in herbal smoking blends sold on websites and in the so-called "smart shops". These compounds, as well as new psychoactive substances, flooded the market of illicit drugs and are sold at street level. Development and validation of rapid analytical methods for the detection and quantification of synthetic cannabinoids in biological matrices are essential for the investigation of pharmacokinetic, pharmacodynamic and toxicological properties. In this pilot study, the potential of direct immersion solid-phase microextraction coupled to GC/MS for the determination of synthetic and natural cannabinoids in oral fluid was proved. Validation proved the suitability of the developed method for the determination of the analytes at trace levels in oral fluid: linearity was assessed in the LOQ - 1000 ng/mL range, whereas a good precision was observed with CV below 20%. The method was then applied to more than 100 real oral fluid samples collected from a population of young students, showing a positivity rate of 3.8%.

Novel sample-substrates for the determination of new psychoactive substances in oral fluid by desorption electrospray ionization-high resolution mass spectrometry.

A reliable screening and non invasive method based on the use of microextraction by packed sorbent coupled with desorption electrospray ionization-high resolution mass spectrometry was developed and validated for the detection of new psychoactive substances in oral fluid. The role of different sample substrates in enhancing signal intensity and stability was evaluated by testing the performances of two polylactide-based materials, i.e. non-functionalized and functionalized with carbon nanoparticles, and a silica-based material compared to commercially available polytetrafluorethylene supports. The best results were achieved by using the non-functionalized polylactide substrates to efficiently ionize compounds in positive ionization mode, whereas the silica coating proved to be the best choice for operating in negative ionization mode. LLOQs in the low µg/L, a good precision with CV% always lower than 16% and RR% in the 83(±4)-120(±2)% range, proved the suitability of the developed method for the determination of the analytes in oral fluid. Finally, the method was applied for screening oral fluid samples for the presence of psychoactive substances during private parties, revealing mephedrone in only one sample out of 40 submitted to analysis.