基于纳米沸石咪唑酯骨架结构材料的涡旋辅助微固相萃取

Micro-solid-phase Extraction Based on Vortex-assisted Nanometer Zeolite Imidazolate Frameworks

环境水样中氯苯类化合物(CBs)含量低(ng/L~μg/L),目前分析仪器直接定量检测较为困难,发展新的样品前处理技术可以有效解决这一问题.本文建立了膜保护纳米沸石咪唑酯骨架结构材料8(NZIF-8)涡旋辅助微固相萃取(VA-μ-SPE)的样品前处理技术,并与气相色谱连用对环境水样中的痕量CBs进行的萃取和分析.考察了洗脱剂、萃取时间、超声洗脱时间以及盐浓度等对萃取效果的影响.在最优化试验条件下,CBs的检出限范围为0.002~0.008 ng/m L,在线性范围为0.1~50 ng/m L时,决定系数(r^2)均大于0.991.在浓度为5 ng/m L的CBs样品中进行5次平行测定,相对标准偏差(RSD%)均小于8.4%.实验结果表明,NZIF-8是优良的固相萃取剂,VA-μ-SPE是一种快速有效的新型样品前处理技术.采用该方法分析了实际水样中的四种CBs,相对回收率为87.9%~111.1%,结果较为满意.

Instrumental analysis is not sensitive enough for the determination of chlorobenzenes due to the low concentration of the analytes in the environmental water samples.Sample preparation is an efficient method to solve this problem.In this study,a nanometer size of metal organic framework material,nanometer sized zeolitic imidazolate framework 8(NZIF-8),was used as a vortex-assisted micro-solid-phase extraction(VA-μ-SPE)sorbent for fast extraction of chlorobenzenes(CBs)from environmental water samples,followed by gas chromatography-mass spectrometric determination.Parameters affecting extraction efficiency such as desorption solvent,vortex time,desorption time and salt concentration were optimized.In the optimized conditions,limits of detection were in the range of 0.002-0.008 ng/m L and linear range was in the range of 0.1-50 ng/m L with determination coefficient>0.991.Relative standard deviations were investigated using a solution with a concentration of 5 ng/m L being extracted with the developed method in a day(n=5),and the obtained relative standard deviations(RSDs)were less than 8.4%.The experimental results showed that NZIF-8 is an efficient sorbent and the developed method is a fast mean of sample preparation.The developed method was applied to determine CBs in water samples and satisfactory recoveries(87.9%-111.1%)were obtained.