Fabrication and evaluation of stationary phases with different morphology from two imidazole-based ligands for nonchiral and chiral electrochromatographic separation.

In this work, two metal-organic porous materials from the two imidazole-based ligands (4-methylimidazole-5-carbaldehyde (aImeIm) and histidine (His)) and the same metal source (Zn(CHCOO)·2HO), namely His-ZIF-93 with a crystal zeolite imidazolate framework and His/aImeIm@Zn with an amorphous networks, were first designed and synthesized by the one-pot method. They were used as the stationary phases (SPs) of open-tubular capillary electrochromatography (OT-CEC) to evaluate and compare their separation performance for the nonchiral and chiral compounds. His-ZIF-93-bonded OT-CEC column successfully separated five families of nonchiral analytes due to the synergistic effect of His and the crystal framework.

Acriflavine-modified UIO-66 ratiometric fluorescent sensor for highly selective and fast detection of hypochlorite in water.

Hypochlorite (ClO) as a kind of highly toxic pollutant has garnered significant interest in detection methods, highlighting the pressing need to develop intelligent functional materials for the qualitative and quantitative analysis of ClO in aqueous solutions. Herein, a ratiometric fluorescent sensor was prepared by the combination of acriflavine (Acr) and UIO-66 via a post-synthetic modification strategy. Acr/UIO-66 exhibited both high crystallinity typical of metal-organic frameworks and demonstrated good fluorescent and thermal stability.

TpBD/UiO-66-NH micro-mesoporous hybrid material as a stationary phase for open tubular capillary electrochromatography.

The excellent stability of covalent organic frameworks (COFs) and the diversity of metal organic frameworks (MOFs) make MOF/COF hybrid materials promising candidates for chromatographic stationary phases. In this paper, a TpBD/UiO-66-NH hybrid material was synthesized through a Schiff-base reaction between TpBD COFs and UiO-66-NH MOFs; characterized using Fourier-transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy; and bonded to a capillary to prepare a TpBD/UiO-66-NH-bonded open tubular capillary electrochromatography (OT-CEC) column. Results suggested that the hybrid material had the crystal morphology of a single COF and MOF, a micro-mesoporous structure, and good thermal stability.

Preparation and application of KCC-1@ZIF-8 for the solid extraction of tetracycline with high adsorption capacity.

In this study, three different materials were prepared: dendritic fiber-type silica (KCC-1), zeolitic imidazolate framework-8 (ZIF-8), and a new composite material called KCC-1@ZIF-8. These materials were synthesized using microemulsion, stirring, and coating methods, respectively. The properties of the materials were characterized using various techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), TGA and X-ray diffraction (XRD).

Dual-functional porphyrinic zirconium-based metal-organic framework for the fluorescent sensing of histidine enantiomers and Hg.

A novel fluorescence sensor based on a porphyrinic zirconium-based metal-organic framework, L-cysteine-modified PCN-222 (L-Cys/PCN-222), was developed to selectively recognize histidine enantiomers and sensitively detect Hg. The dual-functional sensor was successfully prepared the solvent-assisted ligand incorporation method and characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), H nuclear magnetic resonance (H NMR) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, circular dichroism (CD), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption-desorption analyses. L-Cys/PCN-222 not only showed a higher quenching response for L-histidine than that for D-histidine with a fast fluorescent response rate of <40 s but also exhibited low detection limits for L- and D-histidine (2.

Enantioseparation by zeolitic imidazolate framework-8-silica hybrid monolithic column with sulfobutylether-β-cyclodextrin as a chiral additive in capillary electrochromatography.

A zeolitic imidazolate framework (ZIF)-8-silica hybrid monolithic column was prepared by one-step sol-gel method. The stationary phase in the monolithic column was characterized by Fourier-transform infrared spectra, X-ray diffraction, thermogravimetric analysis, nitrogen adsorption/desorption, and zeta potential. The results showed that ZIF-8-silica hybrid monolithic materials had abundant functional groups, good crystallinity, large specific surface area, and good thermal stability.

ZnS:Eu @ZIF-8: Selective formation of ZnS:Eu QDs within a zinc methylimidazole framework for chemical sensing applications.

Light harvesting based on a microporous zeolite imidazole backbone (MOF) has attracted considerable interest as a fluorescent sensor for the detection of analytes. In this work, we have prepared a novel complex containing quantum dots of doped rare earth elements by a one-pot method. to be applied to the fluorescence detection of pollution hazards.

Chiral covalent organic framework-based open tubular capillary electrochromatography column for enantioseparation of selected amino acids and pesticides.

A novel chiral covalent organic framework (CCOF) was synthesized with an imine covalent organic framework TpBD (synthesized via Schiff-base reaction between phloroglucinol (Tp) and benzidine (BD)) modified using (1S)-(+)-10-camphorsulfonyl chloride as chiral ligand by chemical bonding method for the first time, and was characterized by X-ray diffraction, Fourier-transform infrared spectra, X-ray photoelectron spectroscopy, nitrogen adsorption/desorption, thermogravimetry analysis, and zeta-potential. The results revealed that the CCOF had good crystallinity, high specific surface area and good thermal stability. Then, the CCOF was employed as stationary phase in open-tubular capillary electrochromatography (OT-CEC) column (the CCOF-bonded OT-CEC column) for enantioseparation of 21 single chiral compounds (12 natural amino acids including acidic, neutral and basic, 9 pesticides including herbicides, insecticides and fungicides) and simultaneous enantioseparation of mixture amino acids and pesticides with similar structures or properties.

A chiral fluorescent COF prepared by post-synthesis modification for optosensing of imazamox enantiomers.

We report a post-synthesis modification for the preparation of a novel chiral fluorescent covalent organic framework (COF) for selective recognization of imazamox enantiomers. In this study, chiral COF was firstly synthesized via a Schiff-base reaction between 2,5-dihydroxyterephthalaldehyde (Dha) and 1,3,5-tris(4-aminophenyl)benzene (Tab) followed by a nucleophilic substitution using (1S)-(+)-10-camphorsulfonyl chloride as chiral modifier. The resulting regular spherical chiral COF Dha Tab not only presented the high optical efficiency, strong covalent bond structure, good crystallinity, large specific surface area but also showed the specific enantioselectivity and quick identification for imazamox enantiomers among five pesticide enantiomers (S/R-imazamox, acephate, acetochlor, propisochlor and metalaxyl).

A facile imine-linked covalent organic framework doped with a carbon dot composite for the detection and removal of Hg in surface water.

Hg is one of the most toxic chemical species in the water environment, and thus developing a new fluorescent covalent organic framework for both the detection and removal of Hg is highly desirable. Herein, a fluorescent composite, termed TpPa-1 COF@CDs, was synthesized by inverse emulsion polymerization method using an imine covalent organic framework as the supporting material and carbon dots as the fluorescent sensor element. The crystallinity, porosity, rich functional receptors (hydroxyl and amino groups), thermal stability and fluorescent properties of TpPa-1 COF@CDs were characterized.

Preparation of a zeolite imidazole skeleton-silica hybrid monolithic column for amino acid analysis via capillary electrochromatography.

We developed a novel, convenient and low-cost one-pot strategy for preparing a zeolitic imidazolate framework-8 (ZIF-8)-silica hybrid monolithic column by adding ZIF-8 directly to a polymer solution of the silica matrix. The simulated stationary phase and monolithic column prepared under optimal conditions were characterized using X-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectroscopy, thermogravimetric analysis nitrogen physisorption and zeta potential. The results obtained confirmed the successful introduction of ZIF-8 into the silica monolithic column, and the prepared monolithic column exhibited good permeability and physicochemical stability.

Chiral fluorescence recognition of glutamine enantiomers by a modified Zr-based MOF based on solvent-assisted ligand incorporation.

In this study, three types of chiral fluorescent zirconium-based metal-organic framework materials were synthesized using l-dibenzoyl tartaric acid as the chiral modifier by the solvent-assisted ligand incorporation method, which was the porous coordination network yellow material, denoted as PCN-128Y. PCN-128Y-1 and PCN-128Y-2 featured unique chiral selectivity for the Gln enantiomers amongst seven acids and the highly stable luminescence property, which were caused by the heterochiral interaction and aggregation-induced emission. Furthermore, a rapid fluorescence method for the chiral detection of glutamine (Gln) enantiomers was developed.

l-Cysteine modified metal-organic framework as a chiral stationary phase for enantioseparation by capillary electrochromatography.

A new kind of chiral zirconium based metal-organic framework, l-Cys-PCN-222, was synthesized using l-cysteine (l-Cys) as a chiral modifier by a solvent-assisted ligand incorporation approach and utilized as the chiral stationary phase in the capillary electrochromatography system. l-Cys-PCN-222 was characterized by X-ray diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, Fourier-transform infrared spectra, nitrogen adsorption/desorption, circular dichroism spectrum, zeta-potential and so on. The results revealed that l-Cys-PCN-222 had the advantages of good crystallinity, high specific surface area (1818 m g), thermal stability and chiral recognition performance.

One-pot synthesis of a novel chiral Zr-based metal-organic framework for capillary electrochromatographic enantioseparation.

A novel chiral stationary phase (CSP) of Zr-based metal-organic framework, l-Cys-PCN-224, was prepared by one-pot method and applied for the enantioseparation by capillary electrochromatography. The CSP was characterized by X-ray diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, Fourier-transform infrared spectra, nitrogen adsorption/desorption, circular dichroism spectrum, zeta-potential, and so on. The results revealed that the CSP had good crystallinity, high specific surface area (2580 m /g), and good thermal stability.

Dual-emission ratiometric fluorescence probe based on copper nanoclusters for the detection of rutin and picric acid.

In this paper, polyvinylpyrrolidone-templated copper nanoclusters (PVP-CuNCs) were synthesised using a hydrothermal method. Through the electrostatic interaction between PVP-CuNCs and rhodamine 6G, a dual-emission ratiometric fluorescent probe was constructed, and two well-separated emission peaks appeared at 420 nm and 570 nm. The selective detection of rutin and picric acid was achieved by fitting the relationship between the ratiometric fluorescence intensity (F/F) and the concentration of the target detection substance.

A covalent organic framework for chiral capillary electrochromatography using a cyclodextrin mobile phase additive.

Covalent organic frameworks (COFs) have been recognized as promising solid phases in capillary electrochromatography (CEC). Imine-based COF-coated open-tubular CEC column (COF TpBD-coated OT column) was prepared and characterized by X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectra, thermogravimetric analysis (TGA), nitrogen adsorption/desorption (Brunauer-Emmett-Teller [BET]), and scanning electron microscopy (SEM). The results showed that the column efficiency was up to 26,776 plate/m, and the thickness of stationary phase was about 6.

β-Cyclodextrin-modified covalent organic framework as chiral stationary phase for the separation of amino acids and β-blockers by capillary electrochromatography.

Covalent organic frameworks (COFs) as a novel stationary phase have attracted much attention in the field of chromatography owing to their permanent nanoscale porosity, higher surface area, and exceptional stabilities. Here, a novel isocyanate-β-cyclodextrin-modified COF (MDI-β-CD-modified COF) was synthesized using isocyanate-β-cyclodextrin as the chiral selector and imine-based TpPa-1 COF as the matrix by a bottom-up strategy. The reaction condition and the structure of MDI-β-CD-modified COF were optimized and characterized by X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectra, nitrogen adsorption/desorption (Brunauer-Emmett-Teller [BET]), and thermogravimetric analysis (TGA).

Hyphenation of field-amplified sample injection and transient isotachophoresis in CE for the determination of sotalol and metoprolol in human urine samples.

A sensitive approach of capillary electrophoresis coupled with field-amplified sample injection and transient isotachophoresis was developed for the simultaneous determination of two β-blockers: sotalol and metoprolol. In this dual focusing technique, the samples were prepared via only dissolution in ultrapure water and then injected electrokinetically. Phosphate acted as both the background electrolyte and the leading electrolyte.

Determination of sulfamerazine in aquatic products by molecularly imprinted capillary electrochromatography.

A molecularly imprinted monolith was prepared and evaluated for the special selective separation of sulfamerazine (SMR) by capillary electrochromatography (CEC). The single-step polymerization method was applied through thermally immobilized vinyl groups of itaconic acid and a derivatization capillary column using SMR as the template. The monolith with optimal selectivity and permeability was performed at 45°C for 7 h according to the molar ratios of 1 : 4 : 10 (template/functional monomer/cross-linker).

Preparation and characterization of a new open-tubular capillary column for enantioseparation by capillary electrochromatography.

In order to use the enantioseparation capability of cationic cyclodextrin and to combine the advantages of capillary electrochromatography (CEC) with open-tubular (OT) column, in this study, a new OT-CEC, coated with cationic cyclodextrin (1-allylimidazolium-β-cyclodextrin [AI-β-CD]) as chiral stationary phase (CSP), was prepared and applied for enantioseparation. Synthesized AI-β-CD was characterized by infrared (IR) spectrometry and mass spectrometry (MS). The preparation conditions for the AI-β-CD-coated column were optimized with the orthogonal experiment design L (3 ).

Template synthesis of the CuO nanoparticle-doped hollow carbon nanofibres and their application as non-enzymatic glucose biosensors.

The cuprous oxide nanoparticle (CuO NP)-doped hollow carbon nanofibres (CuO/HCFs) were directly synthesized by the anodic aluminium oxide (AAO) template. The doped CuO NPs were formed by deposition by direct reduction reaction of precursor carbonization in thermal decomposition and could act as functionalized nanoparticles. The synthesized CuO/HCFs were characterized in detail by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and inductively coupled plasma mass spectrometry (ICP-MS).

Facile Synthesis and High Activity of Novel Composite C/Fe-BiVO₄ Photocatalyst for Degradation of Cipfloxacin.

A novel C/Fe-BiVO4 nanosheet composite photocatalyst combining the properties of both semiconductor and Fenton like catalyst was prepared via a two-step method involving Resin carbonization and hydrothermal process. The samples were characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM) and energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectra (DRS), X-ray photoelectron spectroscopy (XPS), Fourier transformed infrared spectroscopy (FT-IR) and nitrogen adsorption-desorption measurements and fluorescence spectrum technique. Structure analyses indicated that C/Fe-BiVO4 presented a nanosheet and macro-meso dual porosity structure.

Activity, toxicity, molecular docking, and environmental effects of three imidazolinone herbicides enantiomers.

All imidazolinone (IMI) herbicides are chiral consisting of two enantiomers; however, studies on the enantioselectivities of their interactions are limited. This study is a systematic assessment of the enantiomers and racemates of IMI herbicides, including semi-preparation and determination of absolute configurations, stereoselective bioactivity toward target organisms (Echinochloa crus-galli and Microcystis aeruginosa), and toxicity toward Michigan Cancer Foundation-7 (MCF-7) cells. R-imidazolinones were found to be more active than S-IMIs in the inhibition of target organisms, and neither enantiomer had estrogenic activity.

Behavior and distribution of heavy metals including rare Earth elements, thorium, and uranium in sludge from industry water treatment plant and recovery method of metals by biosurfactants application.

In order to investigate the behavior, distribution, and characteristics of heavy metals including rare earth elements (REEs), thorium (Th), and uranium (U) in sludge, the total and fractional concentrations of these elements in sludge collected from an industry water treatment plant were determined and compared with those in natural soil. In addition, the removal/recovery process of heavy metals (Pb, Cr, and Ni) from the polluted sludge was studied with biosurfactant (saponin and sophorolipid) elution by batch and column experiments to evaluate the efficiency of biosurfactant for the removal of heavy metals. Consequently, the following matters have been largely clarified.