Ultrasensitive analysis of mirtazapine and its metabolites enantiomers in body fluids using ultrasound-enhanced and surfactant-assisted dispersive liquid-liquid microextraction followed by polymer-mediated stacking in capillary electrophoresis

A simple, rapid, and sensitive technique for measuring mirtazapine and its metabolites enantiomers in human fluids, such as urine and serum, was developed by applying ultrasound-enhanced and surfactant-assisted dispersive liquid-liquid microextraction (USA-DLLME) integrated with poly(diallyldimethylammonium chloride) (PDDAC)-mediated stacking in capillary electrophoresis (CE). The parameters that affect extraction and stacking performance, such as the extraction volume, surfactant types, surfactant concentrations, salt additives, extraction time, solution pH, and background electrolytes, were comprehensively studied and optimized to achieve optimal detection performance. Under optimal extraction conditions (injection of 120 µL of C