•Methacrylate-bonded COF TpPa-1 monolithic columns were successfully prepared.•COF monolithic columns show high column efficiency and precisions for HPLC separation.•The results reveal the great potential of COF monolithic columns for HPLC separation.Covalent-organic frameworks (COFs) are a newfangled class of intriguing microporous materials. Considering their unique properties, COFs should be promising as packing materials for high performance liquid chromatography (HPLC). However, the irregular shape and sub-micrometer size of COFs synthesized via the traditional methods render the main obstacles for the application of COFs in HPLC. Herein, we report the preparation of methacrylate-bonded COF monolithic columns for HPLC to overcome the above obstacles. The prepared COF bonded monolithic columns not only show good homogeneity and permeability, but also give high column efficiency, good resolution and precision for HPLC separation of small molecules including polycyclic aromatic hydrocarbons, phenols, anilines, nonsteroidal anti-inflammatory drugs and benzothiophenes. Compared with the bare polymer monolithic column, the COF bonded monolithic columns show enhanced hydrophobic, π-π and hydrogen bond interactions in reverse phase HPLC. The results reveal the great potential of COF bonded monoliths for HPLC and COFs in separation sciences.

A γ-cyclodextrin metal–organic framework was applied as an efficient chiral stationary phase for high-performance liquid chromatographic separation of chiral aromatic alcohols.

The development of the multimodal probes is of great importance for bioimaging application. Herein, we report the fabrication of a functional nanocomposite from near-infrared (NIR) persistent luminescent nanoparticles (PLNPs) and Gd2O3 as a multimodal probe for in vivo NIR persistent luminescence and magnetic resonance (MR) imaging. Small-sized monodispersed NIR ZnGa2O4:Cr3+ PLNPs (ca. 15 nm) were prepared as the NIR persistent luminescence source by a hydrothermal method while hyaluronic acid (HA) functionalized Gd2O3 (HA-Gd2O3) was synthesized as the MR contrast agent via a biomineralization approach. An EDC/NHS coupling strategy was used to connect the amino functionalized PLNPs and the HA-Gd2O3 to give the HA functionalized multimodal probe. The multimodal probe not only exhibits an excellent NIR persistent luminescence signal, but also exhibits larger longitudinal relaxivity (7.38 mM−1 s−1) than commercial contrast agent Gd-DTPA. Moreover, the HA moieties not only enhance the biocompatibility of the multimodal probe, but also endow the probe with tumor-targeting capability. Both in vitro and in vivo bioimaging experiments demonstrate the potential of the multimodal probe for tumor-targeting NIR persistent luminescence and MR imaging.

A simple and facile room-temperature solution-phase synthesis was developed to fabricate a spherical covalent organic framework with large surface area, good solvent stability and high thermostability for high-resolution chromatographic separation of diverse important industrial analytes including alkanes, cyclohexane and benzene, α-pinene and β-pinene, and alcohols with high column efficiency and good precision.

The introduction of a triazole-based ligand to the zeolitic imidazolate framework-7 via a postsynthetic ligand exchange strategy not only maintains its framework, high stability and morphology, but also provides extra uncoordinated nitrogen atoms to improve the π–π and Lewis acid–base interactions.

The unique properties of metal–organic frameworks, such as diversity in structures and pore sizes, high surface area, shape selectivity and available to functionality make them as potential materials of the stationary phase for gas chromatography. Here we show an in situ growth approach to the fabrication of zeolite imidazolate framework-90 (ZIF-90) bonded capillary column for gas chromatography separation. ZIF-90 was directly grown onto the inner wall of the carboxyl modified capillary via the coordination between Zn(II) and carboxyl group. The fabricated ZIF-90 bonded capillary column acted as a weak polar stationary phase. It not only exhibits high capacity in the separation of linear molecules, but also offers excellent features for the separation of 2- and 3-substituted ketones.

•A novel MIL-53(Al) incorporated polymer monolithic column was fabricated.•The monolithic column was applied in polymer monolith microextraction.•The method gave low detection limits for non-steroidal anti-inflammatory drugs.Polymer monolith microextraction (PMME) based on capillary monolithic column is an effective and useful technique to preconcentrate trace analytes from environmental and biological samples. Here, we report the fabrication of a novel aluminum terephthalate metal-organic framework (MIL-53(Al)) incorporated capillary monolithic column via in situ polymerization for the PMME of non-steroidal anti-inflammatory drugs (NSAIDs) (ketoprofen, fenbufen and ibuprofen) in water and urine samples. The fabricated MIL-53(Al) incorporated monolith was characterized by X-ray powder diffractometry, scanning electron microscopy, Fourier transform infrared spectrometry, and nitrogen adsorption experiment. The MIL-53(Al) incorporated monolith gave larger surface area than the neat polymer monolith. A 2-cm long MIL-53(Al) incorporated capillary monolith was applied for PMME coupled with high-performance liquid chromatography for the determination of the NSAIDs. Potential factors affecting the PMME were studied in detail. Under the optimized conditions, the developed method gave the enhancement factors of 46–51, the linear range of 0.40–200 μg L−1, the detection limits (S/N = 3) of 0.12–0.24 μg L−1, and the quantification limits (S/N = 10) of 0.40–0.85 μg L−1. The recoveries for spiked NSAIDs (20 μg L−1) in water and urine samples were in the range of 77.3–104%. Besides, the MIL-53(Al) incorporated monolith was stable enough for 120 extraction cycles without significant loss of extraction efficiency. The developed method was successfully applied to the determination of NSAIDs in water and urine samples.

The development of novel methods for chiral discrimination remains a challenging and important area due to the structural similarity but significantly different roles of enantiomers in biological and environmental systems. Here we report a 3D chiral porous Zn–organic framework (Zn2(bdc)(L-lac)(dmf)·DMF) coated quartz crystal microbalance (QCM) sensor for chiral discrimination of four pairs of enantiomers. The adsorption isotherms of the enantiomers on Zn2(bdc)(L-lac)(dmf)·DMF follow the Dubinin–Astakhov equation. The QCM sensor shows excellent sensitivity and enantioselectivity. The chiral recognition ability of the Zn2(bdc)(L-lac)(dmf)·DMF sensor was temperature and concentration dependent. The chiral selectivity factor ranged from 1.36 (S/R-1-(1-naphthyl)ethylamine) to 2.20 (S/R-1-phenylethylamine) at 25 °C. The good chiral recognition capacities of enantiomers provide Zn2(bdc)(L-lac)(dmf)·DMF potential for the discrimination of enantiomers.

•Pyridine grafted metal–organic framework MIL-101(Cr) was fabricated.•The pyridine-grafted MIL-101(Cr) was used as stationary phase for HPLC.•The pyridine-grafted MIL-101(Cr) column gave baseline separation of tocopherols.Effective separation of tocopherols is challenging and significant due to their structural similarity and important biological role. Here we report the post-synthetic modification of metal–organic framework (MOF) MIL-101(Cr) with pyridine for high-performance liquid chromatographic (HPLC) separation of tocopherols. Baseline separation of four tocopherols was achieved on a pyridine-grafted MIL-101(Cr) packed column within 10 min using hexane/isopropanol (96:4, v/v) as the mobile phase at a flow rate of 0.5 mL min−1. The pyridine-grafted MIL-101(Cr) packed column gave high column efficiency (85,000 plates m−1 for δ-tocopherol) and good precision (0.2–0.3% for retention time, 1.8–3.4% for peak area, 2.6–2.7% for peak height), and also offered much better performance than unmodified MIL-101(Cr) and commercial amino-bonded silica packed column for HPLC separation of tocopherols. The results not only show the promising application of pyridine-grafted MIL-101(Cr) as a novel stationary phase for HPLC separation of tocopherols, but also reveal a facile post-modification of MOFs to expand the application of MOFs in separation sciences.graphical-abstractPyridine-grafted MIL-101(Cr) was explored as a novel stationary phase for high performance liquid chromatographic separation of tocopherols with high resolution, high column efficiency and good precision.

A simple and facile room-temperature solution-phase synthesis was developed to fabricate a spherical covalent organic framework with large surface area, good solvent stability and high thermostability for high-resolution chromatographic separation of diverse important industrial analytes including alkanes, cyclohexane and benzene, α-pinene and β-pinene, and alcohols with high column efficiency and good precision.

The introduction of a triazole-based ligand to the zeolitic imidazolate framework-7 via a postsynthetic ligand exchange strategy not only maintains its framework, high stability and morphology, but also provides extra uncoordinated nitrogen atoms to improve the π–π and Lewis acid–base interactions.