Development of a sensitive MEKC‐LIF method for synthetic cathinones analysis

Synthetic cathinones are phenylalkylamine compounds related to natural
cathinone from Catha edulis leaves. Due to their sympathomimetic effects comparable to
common illicit drugs, these substances are mainly drugs of abuse and constitute the secondmost
frequently seized group of new psychoactive substances. In order to ensure their
regulation and to promote public health, reliable analytical tools are required to track these
substances. In the present study, we developed a CE hyphenated to laser-induced fluorescence
detection method to demonstrate its suitability to perform fast and cost-effective
synthetic cathinones analysis. Fourteen compounds including isobaric compounds and
position isomers were selected to encompass the large panel of chemical structures. To
separate the FITC-labeled analytes (presenting the same negative charge and close mass
to charge ratios), MEKC separation mode was selected. Method selectivity was not suitable
using common surfactants. In this context, alkyl polyethylene glycol ether surfactants
were successfully used as neutral surfactant to overcome this analytical challenge. The
effect of surfactant nature on separation performances and migration behaviors of the analytes
was also studied. Optimal BGE composition included 75 mM borate buffer at pH
9.3 and 0.4 mM of C12E10 surfactant. Final MEKC separation conditions were proposed
to analyze a large panel of synthetic cathinones. This method helped to reach a sensitivity
with LOD from 0.1 to 0.4 nM (pg/mL order).