溶胶-凝胶二氧化硅/聚酰亚胺固相微萃取涂层的制备及其应用

Preparation of silicon dioxide/polyimide solid phase microextraction coating by sol-gel and its application

采用均苯四甲酸酐(PMDA)和4,4-二氨基二苯醚(ODA)共聚得到聚酰胺酸与四乙氧基硅烷水解产生的羟基进行缩合反应,通过硅烷偶联剂KH-550键合在石英纤维表面,经过高温制成聚酰亚胺/二氧化硅复合固相微萃取涂层。通过红外光谱、扫描电子显微镜对涂层的结构、表面形貌进行了分析。采用顶空固相微萃取-气相色谱联用法测定了水中的苯、甲苯、二甲苯,色谱峰面积与浓度的线性相关系数(r)分别为0.9934,0.9967,0.9978,最低检测限分别为0.07mg/L,0.04mg/L,0.06mg/L,相对标准偏差(n=6)分别为4.86%～5.24%,4.03%～4.16%,4.22%～4.65%。

The polyamic acid was synthesized from pyromellitic acid dianhydride(PMDA) and 4,4’-diaminodiphenylether(ODA).Tetraethoxysilane was hydrolyzed to generate the silicon alcohol.After dehydration cyclization at high temperature,the PI/SiO2were formed by the condensation reaction between the polyamic acid and the silicon alcohol.PI/SiO2 were bonded on the quartz fiber surface with coupling agent(KH-550).The solid-phase microextraction coating surface morphology of the coating was observated by scanning electron microscope.The structure of the coating was studied by IR.benzene,toluene and dimethylbenzene in aqueous phase were detected by head space-solid phase microextraction-gas chromatography.In the range from 2~12mg/L,the relationship between the peakarea and concentration of benzene,toluene and dimethylbenzene were linear.The correlation coefficients(r) were 0.9934,0.9967 and 0.9978 respectively.The limits of detection of the benzene,toluene and dimethylbenzene were 0.07,0.04mg/L and 0.06mg/L.The relative standard deviations were 4.86%~5.24%,4.03%~4.16%,4.22%~4.65%(n=6)repectively.