Preparation and characterization of ceramic/carbon coated Fe₃O₄ magnetic nanoparticle nanocomposite as a solid-phase...

A novel solid-phase microextraction (SPME) fiber based on a glass tube coated with ceramic/carbon coated Fe₃O₄ magnetic nanoparticle nanocomposite (C-Fe₃O₄/C MNP) was prepared by sol-gel technique. The carbon coated Fe₃O₄ magnetic nanoparticles were synthesized by a simple hydrothermal reaction and the resultant powder was mixed with sol-gel precursors to prepare C-Fe₃O₄/C MNP. The prepared C-Fe₃O₄/C MNP was deposited on surface of glass tubes as new substrate with a simple method. The results revealed that this procedure was a simple and reproducible technique for the preparation of SPME fibers coated with magnetic nanoparticles. The scanning electron micrographs of the fiber surface revealed a three-dimensional structure which is suitable as SPME adsorbents. Some polycyclic aromatic hydrocarbons (PAHs) were selected as model compounds for evaluating performance of the designed SPME fiber. The analytes were extracted with SPME, and desorbed using acetonitrile via ultrasonication. The extracts were analyzed by high performance liquid chromatography (HPLC) with fluorescence detection. The results demonstrated that the proposed method based on the C-Fe₃O₄/C MNP fiber had wide dynamic linear range (0.01-350 μg L⁻¹) with good linearity (R²>0.990) and low detection limits (0.7-50 pg mL⁻¹). The relative standard deviation ranged from 6.9% to 12.2% for inter-day variations. These fibers were successfully used for the analysis of spiked water samples, which demonstrating the applicability of the home-made C-Fe₃O₄/C MNP fibers.