以1-羟乙基-3-甲基咪唑四氟硼酸(HEMIM[BF4])和1-羟乙基-3-甲基咪唑双三氟甲磺酰亚胺(HEMIM-[N(SO2CF3)2])离子液体为涂层材料,采用溶胶-凝胶方法制备了两种新型的离子液体-羟基硅油(OH-TSO)复合涂层固相微萃取探头,并对溶胶-凝胶反应机理和涂层性能进行了考察.由于阴离子结构不同,两种离子液体-OH-TSO复合涂层的性能也存在一定差异.首先,从表面形貌来看,HEMIM[BF4]-OH-TSO涂层表面孔洞排列更整齐,孔径更小,且大小均一.从热重分析结果来看,HEMIM[N(SO2CF3)2]-OH-TSO涂层具有更高的热稳定性,最高使用温度可以达到360℃.从萃取性能来看,HEMIM[BF4]-OH-TSO涂层对大多数酚类环境雌激素和芳胺的萃取效果明显高于HEMIM[N-(SO2CF3)2]-OH-TSO和未加离子液体的OH-TSO涂层.除此之外,它们还具有较强的抗溶剂冲洗能力,pH应用范围广,重现性好.以HEMIM[N(SO2CF3)2]-OH-TSO涂层为萃取头,采用固相微萃取-气相色谱法测定了实际水体中的芳胺.结果表明,该方法检测限低(6.3~201.3ng/L),线性范围宽(3~4个数量级),重现性好(RSD〈7%),准确度高(回收率87.4%~111.5%).
Two hydroxylethyl-functionalized ionic liquids (ILs),1-(2'-hydroxylethyl)-3-methylimidazolium tetrafluoroborate (HEMIM[BF4]) and 1-(2'-hydroxylethyl)-3-methylimidazolium bis-(trifluoromethanesul-fonyl)imide (HEMIM[N(SO2CF3)2]) were first used as selective stationary phase to prepare ILs-hy-droxyl-terminated silicone oil (OH-TSO) hybrid organic-inorganic coatings for solid-phase microextraction (SPME) by sol-gel technology. The underlying mechanism of the sol-gel reaction was proposed and the successful binding of ILs to the sol-gel substrate was confirmed by FT-IR spectra. The performance of these two ILs-based coatings was somewhat different,depending on the type of anions in ILs structure. Firstly,in contrast to HEMIM[N(SO2CF3)2]-OH-TSO coating,the pores on the surface of HEMIM[BF4]-OH-TSO coating are arranged more orderly and uniformly with a smaller size. Secondly,the HEMIM[N(SO2CF3)2]-based fibers had much higher thermal stability compared with the HEMIM[BF4]-based fibers. Thirdly,the extraction efficiency of HEMIM[BF4]-OH-TSO fiber towards phenolic environmental estrogens and aromatic amines was superior to that of HEMIM[N(SO2CF3)2]-OH-TSO fiber,and OH-TSO fiber without ILs. Moreover,these ILs-based SPME fibers had wonderful solvent resistance,wide useable pH range and good coating preparation reproducibility. Efficient analysis of aromatic amines with headspace SPME-GC was achieved using sol-gel-derived HEMIM[N(SO2CF3)2]-OH-TSO fiber. The method showed linear response over three to four orders of magnitude. The limits of detection were very low,ranged between 6.3 and 201.3 ng/L. The relative standard deviation values were below 7% and the recovery varied from 87.4% to 111.5%.