溶胶-凝胶法制备C_(18)固相微萃取头及其在有机氯农药残留检测中的应用

Preparation of n-Octadecyl Solid-phase Microextraction Fiber and Its Applications in Detection of Organochlorine Pesticide Residues in Water

以十八烷基三乙氧基硅烷(C18-TEOS)、四乙氧基硅烷(TEOS)、乙醇、盐和水酸为原料,采用溶胶-凝胶法制备了十八烷基(C18)固相微萃取头,利用所制备萃取头实现了水样中11种有机氯农药的检测。在优化条件下,使用该萃取头对有机氯农药(OCPs)萃取后用气相色谱/电子捕获检测器(GC/ECD)测定,检出限为0.01～0.24μg/L,相对标准偏差为3.0%～13.3%。该方法用于鱼塘水、湖水及自来水中OCPs的检测,结果满意。所制备的萃取头在不同溶剂中浸泡后,对有机氯农药的萃取性能无明显变化。使用50次后,C18萃取头的萃取性能未变化。结果表明,所制备的C18固相微萃取头涂层均匀,具有多孔结构,稳定性高,有很好的实用价值。

A n-octadecyl（C18） solid microextraction fiber was prepared by sol-gel technology,and used in the extraction of organochlorine pesticides in water samples.The sol-gel solution was prepared by mixing appropriate amount of n-octadecyltriethoxysilan（C18-TEOS）,tetraethoxysilane（TEOS）,ethanol,hydrochloric acid and water.Then the n-octadecyl solid phase microextraction fiber was obtained from the polymerization of the sol-gel solution on the surface of the treated fused-silica fiber.Under the optimum conditions,the detection limits of organochlorine pesticides（OCPs） by gas chromatography with electron capture detector（GC/ECD） after extraction with the new C18 fiber were in the range of 0.01-0.24 μg/L,and the relative standard deviations（RSDs） varied from 3.0% to 13.3%.The method was applied in the detection of organochlorine pesticides in fishpond water,lake water and drinking water with satisfactory results.The extraction ability of the new fiber for OCPs was not changed significantly after it was dipped into four kinds of solutions（e.g.n-hexane,methanol,pH 2.0 and 9.0 water solutions） and repeatedly used for 50 times.The obtained fiber showed several advantages including porous structure,high stability and uniformly coating,and could be used as an alternative to the existing fibers for the extraction of OCPs.