Herein, a development of the solid phase microextraction method is achieved by using nano cubic Co3O4@ GO as a sorbent reinforced in propylene hollow fiber (HF). The Co3O4/graphene oxide composite was prepared by a facile one step method under hydrothermal conditions. The average particle size of the ultra-fine cubic Co3O4 nanoparticles on the surface of graphene oxide was about 90 nm.The X-ray diffraction patterns were also employed to confirm the nanocomposite crystal system of the prepared Co3O4/GO by demonstrating the existence of normal cubic spinel structure of Co3O4 in the matrix of Co3O4/GO.The prepared HF was used as an extracting device for hollow fiber solid phase microextraction (HFSPME) of different acidic drugs such as diclofenac, mefenamic acid, indomethacin and ibuprofen. The extracted analytes were then desorbed by liquid desorption method. To achieve the maximum extraction efficiency, different experimental parameters including extraction time, desorption times, desorption solvent volume, pH, stirring rate and ionic strength were firstly screened and secondly optimized through Placket-Burnman and Box Behnken Design, respectively. Under the obtained optimum condition, the linearity of the method was in the range of 1-200 μgL-1. Finally, to investigate the accuracy o f t h e m e t h o d , d i f f e r e n t t y p e s o f u r i n e a n d p l a s m a s a m p l e s w e r e s u c c e s s f u l l y a n a l y z e d .
