title: Fabrication of cross-linked hydrazone covalent organic frameworks by click chemistry and application to solid phase microextraction.
abstract: 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-1were 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.
authors: College of Chemistry, Jilin University, Changchun, 130012 China.
authors: Mingxue
authors: M
authors: Wu
authors: College of Chemistry, Jilin University, Changchun, 130012 China.
authors: Gang
authors: G
authors: Chen
authors: College of Chemistry, Jilin University, Changchun, 130012 China.
authors: Jiutong
authors: J
authors: Ma
authors: Changchun GeneScience Pharmaceuticals Co., Ltd., Changchun, 130012 China.
authors: Ping
authors: P
authors: Liu
authors: College of Chemistry, Jilin University, Changchun, 130012 China. Electronic address: jiaqiong@jlu.edu.cn.
authors: Qiong
authors: Q
authors: Jia
keywords: Click chemistry; Cross-linked hydrazone covalent organic frameworks; Solid phase microextraction