Electromembrane extraction (EME)-LC-MS/MS of khat: improving separation and determination of bioactive ingredients in traditional plant and vitreous humor.

Abstract

Purpose: Regional traditional plant khat, which have been recreationally used world-wide recently, has been proven to be a mixture of several biologically active ingredients. Herein, a chosen specimen, vitreous humor (VH) and a novel pretreatment, electromembrane extraction (EME), are applied for forensic investigations of such abused plant.

Methods: VH, as an alternative matrix, is being used for evaluating possible compounds more and more; EME, a novel and efficient pretreatment method, is applied to detect the ingredients from natural complex matrices with advantages of a more sustainable microextraction technique. This study aims to analyze the ingredients of khat, norephedrine (NE), norpseudoephedrine (NPE) and cathinone (CTN), as well as their concentrations in VH of khat-treated mice applying EME.

Results: After optimization, 2-ethylnitrobenzene (ENB)/undecanol was used as the support liquid membrane (SLM), HCl (pH = 2) as the acceptor solution, extraction voltage at 60 V, and extraction time for 30 min. The established EME was combined with liquid chromatography-ultraviolet spectrometry (LC-UV) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) to evaluate spiked VH. The LOD of NE, NPE, and CTN were 0.40-1.90 µg/mL with linearity (R² > 0.9624) and repeatability (< 13%).

Conclusions: By this method, NE, NPE, and CTN were detected to be 14.4 ± 0.54 µg/mL, 8.50 ± 0.69 µg/mL, and 90.5 ± 7.88 µg/mL in VH of mice administrated with khat for 28 days.