In the present study, a novel solid-phase microextraction molecularly imprinted polymers (SPME-MIP) fiber based on sol-gel technology was developed. Coupling of SPME with selective MIP coating notably increased the extraction yield. The sol-gel procedure for the preparation of SPME fibers provides several advantages: it could occur under mild conditions, the coating’s porous silica is homogeneous and pure, it has a high surfaces area, and the shape and size of pores are easily controllable [1]. In this work, the fiber was prepared via inserting the modified stainless steel wires in the reaction solution of (3-Aminopropyl) triethoxysilane (APTES) and tetraethylorthosilicate (TEOS) with an acidic catalyst (acetic acid). The SPMEMIP fiber used for selective extraction of phenobarbital in urine samples using high performance liquid chromatography with ultraviolet detection (HPLC-UV). Phenobarbital, as the derivatives of barbituric acid, belong to anticonvulsant drugs and have sedative and hypnotic properties [2]. The synthesized MIPs were characterized by several techniques such as field emission scanning electron microscopy (FESEM), Fourier-transform infrared spectroscopy (FTIR), and thermal gravimetric analysis (TGA). The effects of various influencing parameters on the extraction efficiency of phenobarbital were investigated and optimized. Results showed that the maximum extraction efficiency was obtained under the following conditions: pH of 5, 25 min extraction time, 500 rpm stirring rate, 15 min desorption time, and by using methanol as elution solvent. Furthermore, Langmuir and Freundlich's plot was employed to assess the isotherm study. The binding affinity of the SPME-MIP fiber properly fits with the Langmuir equation with correlation coefficient values 0.9995. The proposed method had linear characteristics in the concentration range of 0.02 to 100 µg mL-1 with a suitable coefficient of determination (0.9983). The limit of detection (LOD) and quantification (LOQ) were 9.88 and 32.9 ng mL-1 , respectively. The repeatability and reproducibility of the prepared fibers were 4.6 and 6.5%, respectively.
