MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-Sen University, No.135, Xingang Xi Road, Guangzhou, Guangdong 510275, China.
Department of Chemistry, Guangdong University of Education, Guangzhou 510303, China.
Anal Chim Acta. 2017 Sep 22;987:38-46. doi: 10.1016/j.aca.2017.08.031. Epub 2017 Aug 26.
This study presents the preparation and the characterizations of six tri-metal centered metal-organic frameworks (tM-MOFs) as solid-phase microextraction (SPME) adsorbents. Possessing different proportions of Al, Ga and In atoms in their frameworks, the tM-MOF-based SPME coatings exhibited different extraction performance towards the organic pollutants. Extraction results showed that the M4 (AlGaIn(OCH)(hfipbb)) coating exhibited the best enrichment ability among six tM-MOFs. In addition, it showed better extraction efficiency towards the analytes than three single-metal centered MOFs coatings and a commercial polydimethylsiloxane (PDMS) coating. The adsorption process of the M4 coating was physical adsorption and it was mainly affected by the diffusion process of the compound from the sample to the material, which is the same with the adsorption processes of the single-metal centered MOFs coatings. Under optimal conditions (extraction time, 3 min; NaCl concentration, 25% (w/v); desorption temperature, 270 °C; extraction temperature, 30 °C), the M4 coating achieved low detection limits (0.13-0.88 ng L) and good linearity (5-2000 and 5-5000 ng L) for benzene series compounds. The repeatabilities (n = 5) for single fiber were between 4.3 and 8.1%, while the reproducibilities (n = 3) of fiber-to-fiber were in the range of 7.9-12.7%. Finally, a M4 coated SPME fiber was successfully applied to the analysis of environmental water samples with satisfactory recoveries (80.8%-119.5%).
本研究制备并表征了六种三金属中心金属有机骨架（tM-MOFs）作为固相微萃取（SPME）吸附剂。这些 tM-MOF 基 SPME 涂层具有不同比例的 Al、Ga 和 In 原子，对有机污染物表现出不同的萃取性能。萃取结果表明，在六种 tM-MOF 中，M4（AlGaIn(OCH)(hfipbb)）涂层具有最好的富集能力。此外，它对分析物的萃取效率优于三种单金属中心 MOF 涂层和一种商用聚二甲基硅氧烷（PDMS）涂层。M4 涂层的吸附过程是物理吸附，主要受化合物从样品扩散到材料的过程影响，这与单金属中心 MOF 涂层的吸附过程相同。在最佳条件下（萃取时间 3 分钟；NaCl 浓度 25%（w/v）；解吸温度 270°C；萃取温度 30°C），M4 涂层对苯系物化合物实现了低检测限（0.13-0.88ng L）和良好的线性范围（5-2000 和 5-5000ng L）。单个纤维的重复性（n=5）在 4.3%至 8.1%之间，而纤维间的重现性（n=3）在 7.9%至 12.7%之间。最后，成功地将涂有 M4 的 SPME 纤维应用于环境水样的分析，回收率令人满意（80.8%-119.5%）。
