Study Of Polymer Composite Coating Material For Solid-phase Microextraction

Solid-phase Microextraction (SPME) is a kind of simple and effective sample preparation technique, which developed in1990s. It extracts of organic molecules through the polymer coatings on the surface of fibers. This technique has important advantages, short operation time, less solvent and sample consumption, it has been widely used in many fields including environmental monitoring, food, medicine and health care. The key part of SPME technique is the coating, preparation of SPME coatings with good thermostability and be used for the analysis of non-volatile and polar biological molecules, is of great significance.In this work, PVA/SiO2solid-phase microextraction coatings were preparated by sol-gel technology, the coating fixed PVA chemically bonded on the surface of fibers and formed organic-inorganic interpenetrating crosslinked network structure after repeated freezing-thawing. The characterization of coatings including infrared, thermal stability, chemical stability, surface morphology and crystallization properties were determined. The extraction performance of coatings were investigated by selecting alcohol compounds, sugars and soysaponins as analysis objects. The results showed that PVA/SiO2coating had good selectivity, the coating which SiO2content of20wt.%had best sufficient selectivity. With GC method, the coating had obvious extraction ability for polar alcohol compounds, RSD were obtained within5%, the reproducibility was good. With UV spectrum method, the coating had obvious extraction ability for glucose, sucrose and Oat β-Glucan, optimized experimental conditions, the best extraction time was5min,5min and8min respectively; desorption time was10min,10min,4min; Extraction temperature was65℃; salt concentration was0,0,0.5gmL-1respectively, RSD (n=3) was obtained10.2%,6.9%and8.4%, it showed a good reproducibility. With HPLC method, the coating had significant extraction ability for Soyasaponin Ⅴ, Ⅳ and Ⅱ.In this work, mesoporous amino-SiO2solid-phase microextraction coating was prepared by sol-gel method. Glycerol as the template agent, ethylorthosilicate (TEOS) and3-aminopropyltriethoxysilane (KH550) were reacted under acid condition, obtained mesoporous amino-Si02materials with amino functional groups. The coating was characterized by FTIR, SEM, N2-adsorption-desorption, contact Angle and small Angle X-ray diffraction (SAXD), the results showed that the coating had a larger specific surface area, strong hydrophilicity and porous structure.