Development of a novel ultrasonic-assisted magnetic dispersive solid-phase microextraction method coupled with high performance liquid chromatography for determination of mirtazapine and its metabolites in human urine and water samples employing experimental design

Ultrasonic-assisted magnetic dispersive solid-phase microextraction coupled with high performance liquid chromatography has been developed for extraction and determination of mirtazapine, N-desmethyl mirtazapine, and 8-hydroxy mirtazapine in human urine and water samples. Magnetic graphene oxide-polyaniline nanocomposite (MGOPA) as a novel SPME sorbent was synthesized and used for the microextraction process. The analytical performance of MGOPA was compared with magnetic graphene oxide nanocomposite and indicated that the new sorbent was quite effective for extraction of mirtazapine, N-desmethyl mirtazapine, and 8-hydroxy mirtazapine. A two-stage experimental design approach, Plackett-Burman screening design and Box-Behnken optimization design, was used for screening and optimizing of significant variables in the microextraction process. The practical applicability of the proposed method was assessed by studying the linearity, intra-day and inter-day accuracy, enrichment factor, and precision. This method can be satisfactorily applied to the determination of mirtazapine and its metabolites in human urine and environmental water samples.