Wu Mingxue, Chen Gang, Ma Jiutong, Liu Ping, Jia Qiong
College of Chemistry, Jilin University, Changchun, 130012 China.
Changchun GeneScience Pharmaceuticals Co., Ltd., Changchun, 130012 China.
Talanta. 2016 Dec 1;161:350-358. doi: 10.1016/j.talanta.2016.08.041. Epub 2016 Aug 16.
Covalent organic frameworks (COFs) are an emerging class of porous organic frameworks with diverse promising applications. Herein, we presented the first example of cross-linked hydrazone COFs (cross-linked COFs) coating via thiol-ene click chemistry for solid phase microextraction (SPME). Strong covalent bonds and interlayer of the prepared networks ensured the adsorption capacity and durability of the novel SPME fiber. π-π conjugated structure existed because of abundant phenyl rings and -C=N groups in the cross-lined COFs. A series of characterizations indicated that the cross-linked COFs possessed large surface areas, high porosities and stabilities as well as hydrophobicities. The fiber was applied to SPME of pesticide residues coupled with gas chromatography with an electron capture detector (GC-ECD). Under the optimum experimental conditions, enhancement factors in the range of 2190-10,998 were obtained, illustrating that the cross-linked COFs possessed remarkable preconcentration ability. The low detection limits of 0.0003-0.0023ngkg were achieved with relative standard deviations (RSDs) in the range of 3.4-7.6% (intra-batch) and 5.7-11.6% (inter-batch), respectively. Recovery values in the range of 78.2-107.0% were obtained when the SPME-GC method was applied to the analysis of pesticides in cucumber samples.
共价有机框架（COFs）是一类新兴的多孔有机框架，具有多种有前景的应用。在此，我们展示了通过硫醇-烯点击化学制备用于固相微萃取（SPME）的交联腙COFs（交联COFs）涂层的首个实例。所制备网络的强共价键和层间结构确保了新型SPME纤维的吸附容量和耐久性。由于交联COFs中存在丰富的苯环和-C=N基团，存在π-π共轭结构。一系列表征表明，交联COFs具有大表面积、高孔隙率、稳定性以及疏水性。该纤维应用于农药残留的SPME，并与带有电子捕获检测器（GC-ECD）的气相色谱联用。在最佳实验条件下，获得了2190 - 10998范围内的增强因子，表明交联COFs具有显著的预浓缩能力。实现了0.0003 - 0.0023 ng/kg的低检测限，相对标准偏差（RSD）分别在3.4 - 7.6%（批内）和5.7 - 11.6%（批间）范围内。当将SPME - GC方法应用于黄瓜样品中农药的分析时，回收率在78.2 - 107.0%范围内。
