Preparing And Application Of Nano-silica/Polyurethane As Solid-Phase Microextraction Coating

Solid-phase microextraction technology is a new extraction techniques and it has theadvantages of convenient operation、rapid separation and analysis、high sensitivity、andless sample consumption. The technology has been widely applied in environmental pollution,food testing, medical and other fields. In this paper, nano-silica/polyurethane copolymer wassynthesized by nano-silica, toluene-2,4-discarnate, polypropylene glycol and1,6–hexanediol,as raw materials,ditin butyl dilaurate as catalyst and toluene as solvent. In the course ofpreparation, infrared spectrum was employed to characterize the raw materials, midbody andproduct, according to the change of the characteristic absorption peak intensity of isocyanategroups, the reaction temperature, the reaction time and other influencing factors wereselected and optimized on the synthetic reaction of SPME coating material; Thethermostability of the coating material was investigated by thermal analysis. Solid-phasemicroextraction head was made by nano-silica/polyurethane copolymer coated on quartzfiber. Surface appearance, components and distribution of elements of the extraction headwere analy zed and observed by Scanning electron microscopy and X-ray spectroscopy. Themethod of copolymer coated on quartz fiber surface was researched, and the SPMEequipment was made by homemade SPME head, with gas chromatography coupled,application test of the extraction head was carried out, and the extraction efficiency of theextraction head was investigated, and the factors that affect the extraction efficiency.TheSPME device was used to determine toluene and O-xleney and M-xylene and P-xylene inwater by the method of head space solid phase microextraction gas chromatography. Thelinearity relation between the concentration of toluene and chromatography peak height wasy=0.1423x+0.0096, correlation efficient(R2) was0.9981, minimum detectablility was0.01mg/L; The linearity relation between the concentration of O-xleney and relative peakheight was y=0.0661x-0.0025, correlation efficient(R2) was0.9982, minimum detectablilitywas0.008mg/L; The linearity relation between the concentration of M-xylene and relativepeak height was y=0.1278x-0.0516, correlation efficient(R2) was0.9980, minimumdetectablility was0.005mg/L; The linearity relation between the concentration of P-xyleneand chromatography peak height was y=0.0588x+0.005, correlation efficient(R2) was0.9979,minimum detectablility was0.006mg/L. The result showed that nano-silica/polyurethane copolymer as the SPME coating, it has high extraction performance, good thermal stability,and low prices.