Ultrasound-assisted dispersive solid-phase microextraction of capecitabine by multi-stimuli responsive molecularly imprinted polymer modified with chitosan nanoparticles followed by HPLC analysis

An ultrasonic-assisted dispersive solid-phase microextraction was developed by a multi-stimuli responsive molecularly imprinted polymer based on chain transfer agent-modified chitosan nanoparticles for enrichment and separation of trace capecitabine in a real sample. The synthesized particles were carefully characterized and it was found that a uniform pH-sensitive imprinted polymeric shell is obtained on the surface of Fe₃O₄@chitosan core with enough saturation magnetization (29 emu g⁻¹). Desirable adsorption capacity (91 mg g⁻¹) and high imprinting factor (IF = 3.6) toward capecitabine were exhibited by the Langmuir isotherm model. Under optimized conditions, which were achieved by experimental design, the detection limit (S/N = 3) was 1.9 ng mL⁻¹. The obtained relative mean recoveries of capecitabine using high-performance liquid chromatography were in the range of 93 to 102% in a human plasma sample with RSD less than 5.5%.