多规格硅橡胶萃取棒的萃取性能研究

Performance of several home-made silicone rubber stir bars

采用溶胶-凝胶-硫化法,以甲基乙烯基硅橡胶和乙烯基封端硅橡胶为原料,制备了6种规格的搅拌棒,分别为2 cm(涂层3 mg、8 mg、13 mg)和1 cm、2 cm、3 cm(涂层皆8 mg)。以多环芳烃为目标分析物,考察了搅拌棒的萃取效率。结果表明,萃取条件不变,分子量小的多环芳烃,增加涂层厚度或体积,可提高萃取效率。分子量大的多环芳烃,要提高萃取效率,除具备一定的萃取体积,还要有足够的表面积。用长度1 cm(涂层3 mg、6 mg)、长度2 cm(涂层3 mg)、长度3 cm(涂层6 mg、13 mg)的搅拌棒,优化条件下,萃取5 min^30 min时,多环芳烃的检出限2 ng/L^140 ng/L,各组分峰面积的相对标准偏差小于12%。实际样品雨水的分析,发现了萘及苊的存在。

Sorptive extraction stir bars with different lengths and coating thicknesses were prepared by a new procedure named sol-gel-sulfurization from methyl-vinyl and vinyl-terminated silicone rubbers.The stir bars were 2 cm long(mass of coating,3 mg,8 mg,13 mg),1 cm,2 cm and 3 cm(all of 8 mg),respectively.The extraction efficiencies for polycyclic aromatic hydrocarbons(PAHs) were investigated.The results indicates that the extraction for the smaller PAHs can be increased by the bars with a thicker or a larger volume of silicone coating,whereas for those larger molecules the promotion of sorption needs enough surface area as well as enough volume of the sorptive phase.The limits of detection(LODs) for analysis of PAHs by using several stir bars,1 cm(3 mg,6 mg),2 cm(3 mg) and 3 cm(6 mg,13 mg),were in the range of 2~140 ng/L with the relative standard deviations(RSDs) less than 12%.Naphthalene and acenaphthene were found in the rain water collected from the vicinity of a coal-burning boiler room.