Microporous organic polymers (MOPs) are an emerging class of functional porous materials for diverse potential applications. Typically, tailored microporous structures of MOPs are generated by linkages of organic polymerizable monomer building blocks, providing high permanent porosity and excellent stability. Herein, we reported the first example of the application of organic building block based MOPs (OBB-MOPs) as efficient enrichment media for sample preparation. A novel multilayer interbridging strategy was proposed to fabricate OBB-MOP coatings, and hereby SNW-1 (a kind of OBB-MOPs) was coated on silica substrate with well-controlled thickness. Strong covalent bonds throughout the network and interlayer bridging improved the durability of the coating significantly. Outstanding chemical stability was observed in diverse solvents as well as solutions with a wide range of pH or high ionic strength and even under extremely harsh conditions like boiling water. The SNW-1 coating possessed a microporous network structure constructed of conjugated and nitrogen-rich building blocks. Thus, the coating exhibited a superior enrichment performance of polycyclic aromatic hydrocarbons and volatile fatty acids (VFAs) over commercial coatings based on interactions including π–π affinity and acid–base interaction. For further application, this coating was combined with gas chromatography/mass spectrometry for the noninvasive analysis of VFAs from tea leaf and tobacco shred samples. The low detection limits of 0.014–0.026 μg/L were achieved with the relative standard deviations (RSDs) between 4.3 and 9.0%. Consequently, trace original VFAs from the samples were detected. Good recoveries were obtained in the range of 90–129% and 77–118% with the corresponding RSDs (n = 3) of 2.6–9.3% and 1.9–10%, respectively.
A covalent organic framework, Schiff base network-1 (SNW-1), was synthesized and incorporated into cellulase based poly(glycidyl methacrylate-co-ethylene dimethacrylate) (cellulase@poly(GMA-EDMA-SNW-1)) monolith to afford a novel chiral stationary phase for capillary electrochromatography (CEC). SNW-1 is attractive as a stationary phase for CEC because it not only features high surface areas but also provides conjugate structures and abundant amine groups to give π-π electrostatic stacking and hydrogen bonding property. Incorporation of SNW-1 into monolithic column could improve the column efficiency and increase the interactions between the tested racemates and the stationary phase thus significantly improved their CEC separation. The obtained monoliths were characterized by scanning electron microscopy, elemental analysis and nitrogen adsorption. Moreover, effects of SNW-1 concentration, immobilization pH of cellulase and CEC conditions were also investigated. Under the optimized conditions, the cellulase@poly(GMA-EDMA-SNW-1) monolith exhibited excellent enantioseparation performance for eight pairs of different classes of chiral drugs including β-blockers, antihistamines and anticoagulants. Satisfactory repeatability was achieved with relative standard deviations for intra-day, inter-day and column-to-column runs less than 4.5%, and batch-to-batch runs less than 6.8%. The experiment results reveal that the combination of the versatile features of monoliths and unique properties of SNW-1 could be a promising strategy for chiral separation.
危险品化学品经营许可证（带存储）