Study On Preparation And Properties Of Silicone Modified Polyurethane Solid Phase Micro Extraction Coating

The appropriate pre-treatment methods for purification, separation and enrichment should be applied to analysis the complex matrix and the low content sample in the component to be measured. The weaknesses of requiring a large amount of solvent, low selectivity and large error often were existed in the traditional pre-treatment methods. The solid phase micro extraction(SPME) technique was not only simple and convenient, but was provided with the advantages of rapid analysis, small sample volume and high selectivity. The extraction process of SPME dependented on the partition coefficient of the analyte between the coatings and the sample. The selectivity of SPME depended on the characteristics of the coating materials. Moreover, the sensitivity of the methods determined the volume of the coatings. The “Like dissolves” principle was abided by the first coating in the SPME needles for adsorption of organics. Therefore, the organic compounds in different nature should be used to the SPME needles in different materials. Because of less commercialization SMPE needles in support material and poor stability of their coatings, research workers for chromatography have been exploring new coating materials and coating preparation technology. In this paper, the silicone-modified polyethylene glycol polyurethane was successfully synthesized by toluene-2,4-diisocyanate, polyethylene glycol and hydroxy silicone oil as raw materials, stannous octoate as catalyst and in cyclohexanone solvent. The performance was studied by IR spectroscopy, thermal analysis and scanning electron microscopy. The SMPE needles were prepared coating the copolymer on the on the quartz filaments. The micro-injector was combined with the SMPE needles to produced the solid phase micro-extraction device. The directed extraction of four kinds of plasticizers dimethyl phthalate, diethyl phthalate, dibutyl phthalate and dioctyl phthalate in water was detected by the MS gas chromatography. The results showed that the copolymer was not only strong and not easy to fall off, it could have but also strong adsorption performance and high temperature resistance by combination with the quartz fiber. The surface of the coating of the SPME needle was smooth and the distribution of elements on it was uniformity. The chromatographic peak area and concentration of 4 kinds of tested substance showed a good linear relationship. The linear correlation coefficient(R2) were 0.9958、0.9968、0.9977 and 0.9971, respectively. The limit of detection were 0.065 mg/L、0.078 mg/L、0.087 mg/L and 0.093mg/L, respectively. The relative standard deviation(n = 5) were 7.4%、8.3%、6.7% and 7.9%, respectively. The recoveries were 79.45%、79.49%、78.67% and 81.35%, respectively.