Microextraction by packed sorbent clean-up for the determination of selected synthetic cathinones in hair samples

Simão, A.; Margalho, Cláudia; Dinis, P.; Andraus, M.; Barroso, Mário; Gallardo, E.

http://hdl.handle.net/10400.26/53926

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Background and aims: The use of synthetic cathinones (SC), also known as "bath salts," has been increasing in recent years, leading to a growing concern about their effects on public health. Different clean-up approaches have already been studied by different authors. However, microextraction by packed sorbent (MEPS), a miniaturized form of solid-phase extraction, has not been explored extensively for the determination of SC in hair samples. Therefore, we propose the optimization of the MEPS procedure as sample clean-up method followed by gas chromatography mass spectrometry for the determination of these analytes in hair samples. Methods: Hair samples were washed consecutively with dichloromethane, deionized water and methanol to remove dirt and externally deposited material. After drying, hair was scissor-cut into small fragments. Fifty milligrams of hair were incubated overnight in the presence of 1 M NaOH at 45 °C, after which the extracts were neutralized and subjected to MEPS using a C8-SCX cartridge. The compounds were analyzed underivatized by GC-MS in the SIM mode. MEPS conditions were conditioning (250 μL of methanol followed by 250 μL of water), sample loading (24 x 700 μL of hair extract) and elution (7 x 100 μL of 2% NH4OH in acetonitrile). Results and discussion: The procedure resulted in acceptable recoveries (15-59% for all analytes), and allowed reaching lower limits of quantification (LLOQs) of 100 pg/mg for 4-MDMB, 4-MNEB and 4- MDMP and of 200 pg/mg for the remaining analytes (4-CEC, 4-MNEP, 4-MDEB, 4-MDMH, ethylone, alpha-PVP, penthylone, 4-Cl-PVP, MPHP and MDPV). Conclusions: In this work the optimization of the MEPS technique coupled to GC-MS for the determination of selected synthetic cathinones in hair samples is presented. The method was considered suitable for the analysis of these compounds in hair, providing acceptable recoveries and obtaining low limits of quantification.