Yan-Yan Fu

Incorporation of metal–organic framework UiO-66 into porous polymer monoliths to enhance the liquid chromatographic separation of small molecules

UiO-66 incorporated monoliths were fabricated to enhance the liquid chromatographic separation of small molecules with high column efficiency and good reproducibility.

Fabrication of ZIF-8@SiO2 core-shell microspheres as the stationary phase for high-performance liquid chromatography.

The unique features of high porosity, shape selectivity, and multiple active sites make metal-organic frameworks (MOFs) promising as novel stationary phases for high-performance liquid chromatography (HPLC). However, the wide particle size distribution and irregular shape of conventional MOFs lead to lower column efficiency of such MOF-packed columns. Herein, the fabrication of monodisperse MOF@SiO2 core-shell microspheres as the stationary phase for HPLC to overcome the above-mentioned problems is reported. Zeolitic imidazolate framework 8 (ZIF-8) was used as an example of MOFs due to its permanent porosity, uniform pore size, and exceptional chemical stability. Unique carboxyl-modified silica spheres were used as the support to grow the ZIF-8 shell. The fabricated monodisperse ZIF-8@SiO2 packed columns (5 cm long × 4.6 mm i.d.) show high column efficiency (23,000 plates m(-1) for bisphenol A) for the HPLC separation of endocrine-disrupting chemicals (bisphenol A, β-estradiol, and p-(tert-octyl)phenol) and pesticides (thiamethoxam, hexaflumuron, chlorantraniliprole, and pymetrozine) within 7 min with good relative standard deviations for 11 replicate separations of the analytes (0.01-0.39, 0.65-1.7, 0.70-1.3, and 0.17-0.91% for retention time, peak area, peak height, and half peak width, respectively). The ZIF-8@SiO2 microspheres combine the advantages of the good column packing properties of the uniform monodisperse silica microspheres and the separation ability of the ZIF-8 crystals.

Metal-organic framework MIL-100(Fe) as the stationary phase for both normal-phase and reverse-phase high performance liquid chromatography.

Metal-organic framework MIL-100(Fe) was explored as a novel stationary phase for both normal-phase and reverse-phase high performance liquid chromatography. Two groups of analytes (benzene, toluene, ethylbenzene, naphthalene and 1-chloronaphthalene; aniline, acetanilide, 2-nitroaniline and 1-naphthylamine) were used to test the separation performance of MIL-100(Fe) in the reverse-phase mode, while the isomers of chloroaniline or toluidine were employed to evaluate its performance in the normal-phase mode. The MIL-100(Fe) packed column gave a baseline separation of all the tested analytes with good precision. The separation was controlled by negative enthalpy change and entropy change in the reverse-phase mode, but positive enthalpy change and entropy change in the normal-phase mode. The relative standard deviations of retention time, peak area, peak height, and half peak width for eleven replicate separations of the tested analytes were 0.2-0.7%, 0.5-3.6%, 0.6-2.3% and 0.8-1.7%, respectively. The mesoporous cages, accessible windows, excellent chemical and solvent stability, metal active sites and aromatic pore walls make MIL-100(Fe) a good candidate as a novel stationary phase for both normal-phase and reverse-phase high performance liquid chromatography.

Control of the coordination status of the open metal sites in metal-organic frameworks for high performance separation of polar compounds.

Metal-organic frameworks (MOFs) with open metal sites have great potential for enhancing adsorption separation of the molecules with different polarities. However, the elution and separation of polar compounds on such MOFs packed columns using nonpolar solvents is difficult due to too strong interaction between polar compounds and the open metal sites. Here, we report the control of the coordination status of the open metal sites in MOFs by adjusting the content of methanol (MeOH) in the mobile phase for fast and high-resolution separation of polar compounds. To this end, high-performance liquid chromatographic separation of nitroaniline, aminophenol and naphthol isomers, sulfadimidine, and sulfanilamide on the column packed with MIL-101(Cr) possessing open metal sites was performed. The interaction between the open metal sites of MIL-101(Cr) and the polar analytes was adjusted by adding an appropriate amount of MeOH to the mobile phase to achieve the effective separation of the polar analytes due to the competition of MeOH with the analytes for the open metal sites. Fourier transform infrared spectra and X-ray photoelectron spectra confirmed the interaction between MeOH and the open metal sites of MIL-101(Cr). Thermodynamic parameters were measured to evaluate the effect of the content of MeOH in the mobile phase on the separation of polar analytes on MIL-101(Cr) packed column. This approach provides reproducible and high performance separation of polar compounds on the open metal sites-containing MOFs.

In situ hydrothermal growth of a dual-ligand metal–organic framework film on a stainless steel fiber for solid-phase microextraction of polycyclic aromatic hydrocarbons in environmental water samples

Effective enrichment and determination of polycyclic aromatic hydrocarbons (PAHs) in environmental aqueous solutions is still a major challenge because of their poor solubility and low concentration in the environmental matrix. Solid-phase microextraction (SPME) has been proven to be an effective technique for analyzing trace analytes from environmental samples. Herein, we report the fabrication of a dual-ligand metal–organic framework (MOF) bio-MOF-1-coated stainless steel fiber via an in situ growth approach for SPME of six PAHs in water samples. Such MOF-based SPME in combination with gas chromatography (GC) gave enhancement factors of 3104–5980, ranges of 10–100 μg L−1 for Nap, Ace, and Fle, 2.5–100 μg L−1 for Phen, 0.1–100 μg L−1 for FluA and Pyr, detection limits (S/N = 3) of 0.02–5.57 μg L−1, and quantitation limits (S/N = 10) of 0.14–17.2 μg L−1 for the studied PAHs. The recoveries obtained by spiking 10 μg L−1 PAHs in water samples ranged from 80% to 115%. The results showed that π–π interaction with biphenyldicarboxylate and π-complexation between aromatic rings and the pyrimidine in the pores of bio-MOF-1 play significant roles in the extraction of PAHs.

Hyaluronic acid-mediated one-pot facile synthesis of a sensitive and biocompatible Gd2O3 nanoprobe for MR imaging in vivo

MR contrast agents play a crucial role in the early diagnosis of various diseases, and many nanoprobes with versatile properties have been developed. However, in order to seek high sensitivity, the biocompatibility and systemic toxicity assessment of the nanoprobes have attracted much less attention. To meet clinical requirements, it is highly desirable to develop a highly sensitive and biocompatible nanoprobe using a facile procedure. Herein, we report a sensitive and biocompatible Gd2O3 nanoprobe using hyaluronic acid (HA) via a one-pot facile synthesis. HA not only endows the nanoprobe with excellent biocompatibility, but also gives a synergistic effect for improving the sensitivity of the nanoprobe in the aspects of increasing rotational correlation time, water exchange rate and the ratio of surface Gd3+ to the inner ones. What’s more, the nanoprobe has specific ability for adrenal gland MR imaging. These results suggest that the HA–Gd2O3 nanoprobe has a potentially promising application in MR imaging in vivo.

Biomineralization of Versatile CuS/Gd2 O3 Hybrid Nanoparticles for MR Imaging and Antitumor Photothermal Chemotherapy.

The versatile application of nanoparticles in integrating imaging and therapy has aroused extensive research interest in precision medicine. Of the various nanoparticles that have been studied, CuS has shown great potential in the construction of multifunctional agents, owing to its excellent photothermal heating properties. Herein, we report a facile one-pot biomineralization approach for the preparation of versatile bovine-serum-albumin-conjugated CuS/Gd2 O3 hybrid nanoparticles (BSA-CuS/Gd2 O3 HNPs), which simultaneously possessed strong longitudinal relaxivity, an outstanding photothermal effect, high drug-loading capacity, and pH/temperature-responsive drug release. The versatile nanoparticles were used for magnetic resonance imaging (MRI) and antitumor photothermal chemotherapy, both in vitro and in vivo. In vivo MRI showed that the BSA-CuS/Gd2 O3 HNPs had a long circulation time and effective passive tumor-uptake ability. More importantly, combined in vitro and in vivo therapy demonstrated that drug-loaded BSA-CuS/Gd2 O3 HNPs offered outstanding synergistic therapeutic efficacy for tumor inhibition.