Corn-like stationary phase for solid phase microextraction prepared by electro-assisted deposition of sol-gel/silica nanoparticles composite

A novel solid phase microextraction (SPME) fiber was fabricated based on the electrophoretic and electrochemical deposition of silica nanoparticles and silicon alkoxides as sol-gel precursors. The surface of the Cu support was initially modified by a self-assembled monolayer (SAM) of (3-mercaptopropyl) trimethoxysilane (3MPTS). Then, the composite coating was electrodeposited on the modified substrate. The SEM images showed that porous and corn-like particles of composite were coated on the Cu wire substrate. The prepared composite was used as SPME fiber and applied to extract some halogenated benzenes from aqueous solution as model compounds. Parameters affecting the extraction efficiency such as extraction temperature, extraction time, and ionic strength were evaluated and optimized. Then, the extraction efficiency of the new fiber was evaluated by determining the limit of detection (LOD), linear dynamic range (LDR) and relative standard deviation (RSD). Using GC-MS determination of analytes it was found that LOD, LDR, and RSD of this method were between 0.1 and 0.6 mu g L-1, 0.5-100 mu g L-1 and less than 14.4%, respectively. The thermal stability of the fiber was investigated by thermogravimetric analysis, and finally, results show that each fiber is usable at 280 degrees C (3 min) for more than 80 times. Furthermore, the proposed fiber was successfully applied for quantification of halogenated benzenes in real water samples.