In the current study, solid phase microextraction (SPME) and hollow fiber three phase liquid microextraction (HF-LLLME) techniques have been combined to improve microextraction methods. The selective anion-exchange Zn-Al-layered double hydroxide (Zn-Al-LDH) as a fiber SPME has been electrodeposited on the surface of pencil graphite substrate [1]. The electrosynthesized Zn-Al-LDH sorbent was characterized by different methods such as Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), thermal gravimetric analysis (TGA) and then put into the lumen of HF which was filled by alkaline solution. The HF is utilized for achieving the excellent sample clean-up by preventing diffusion of interferences [2-3]. The pores of polypropylene hollow fiber are impregnated by an appropriate organic solvent. To obtain the high extraction efficiency, different parameters were optimized through response surface method. In the proposed method, HF-LLLME-SPME configuration was applied for extraction and determination selected antibiotics including amoxicillin, ciprofloxacin and cefixime in urine samples. The extracted antibiotics were analyzed through high performance liquid chromatography-ultraviolet detection (HPLC-UV). Under optimal conditions, the inter-day and intra-day RSDs were determined between 3.2-4.7%. The results confirmed the presented method would be useful for the analysis of different types of drugs in complicated biological samples.
