A core-shell structured magnetic covalent organic frameworks of the type FeO@COFs was prepared by using the FeO nanoparticles as magnetic core, and 4,4"-diamino-p-terphenyl and 1,3,5-tris(p-formylphenyl)benzene as two building blocks. The FeO@COFs were characterized by scanning electron microscopy, transmission electron microscopy, energy dispersive spectrum, Fourier transform infrared spectroscopy, zeta potentiometric analysis, X-ray diffraction, vibrating sample magnetometry, thermogravimetric analysis and the nitrogen adsorption-desorption isotherms. The FeO@COFs have core-shell structure with average diameter of 200 ± 2.4 nm, a high specific surface area (124 m·g), uniform pore size distribution (3.1 nm), good magnetic responsivity (36.8 emu·g), good thermal and chemical stability. They were applied as the sorbents for magnetic solid phase extraction (MSPE) for fluoroquinolones (FQs) ciprofloxacin, enrofloxacin, lomefloxacin, gatifloxacin, levofloxacin and pefloxacin. The effects of sorbent dosage, extraction time, p H value, ionic strength, desorption solvent and desorption time were investigated. By combining MSPE with HPLC-DAD analysis, a rapid and sensitive method was developed for the enrichment and determination of these FQs. The method had good linearity in the range of 2.5-1500 ng·g FQ concentration range and low limits of detection (0.25-0.5 ng·g). The method was successfully applied to the extraction and determination of FQs in (spiked) pork, milk and human plasma samples. Recoveries ranged from 78.7-103.5% (with RSD<6.2%). Graphical abstract Schematic representation of the magnetic covalent organic frameworks which prepared by using the FeO nanoparticles as magnetic core, 4,4"-diamino-p-terphenyl and 1,3,5-tris(p-formylphenyl)benzene as two building blocks. The FeO@COFs were applied as adsorbents for magnetic solid phase extraction of six fluoroquinolones (FQs) and HPLC-DAD was applied to analysis the extraction efficiencies.
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Int J Biol Macromol
January 2025
Department of Chemical Engineering Materials Environment, Sapienza University of Rome, Via Eudossiana 18, 00184 Rome, Italy.
This study introduces a sustainable approach for enhancing the fire retardancy and smoke suppression of poly(lactic acid) (PLA) composites, contributing to addressing one of the major challenges in biocomposites that limits their application in various engineering fields, as automotive and construction sectors. Flax fibers (FF) were surface functionalized with a novel organic-inorganic hybrid flame retardant (FR), offering a sustainable bioinspired approach that mitigates potential mechanical properties impairment and FR leaching, which can cause environmental concerns and reduced composite durability. The process involves a three-step coating procedure.
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January 2025
Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA.
Van der Waals materials display rich structural polymorphs with distinct physical properties. An atomistic understanding of the phase-transition dynamics, propagation pathway and associated evolution of physical properties is essential for capturing their potential in practical technologies. However, direct visualization of the rapid phase-transition process is fundamentally challenging due to the inherent trade-offs among atomic resolution, field of view and imaging frame rate.
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January 2025
College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China.
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February 2025
College of Chemical Engineering and Environment, China University of Petroleum-Beijing, Beijing 102249, China.
Trace contaminants are toxic and their widespread presence in the environment potentially threatens human health. The levels of these pollutants are often difficult to determine directly using instruments owing to the complexities of environment matrices. Hence, pretreatment steps, such as sample purification and concentration, are key along with various processes that enhance the accuracy and sensitivity of the detection method.
View Article and Find Full Text PDFInorg Chem
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Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States.
Three new hexagonal perovskites with CsMMRhCl (M = Na, Ag; M = Mn, Fe) stoichiometry have been synthesized from solution precipitation reactions. These air-stable compounds crystallize as triply cation-ordered variants of the 6H perovskite structure. This structure contains octahedra that share a common face to form MRhCl dimers that are arranged on a two-dimensional triangular network.
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