No abstract

No abstract

Green photoluminescent graphene quantum dots (GQDs) were synthesized from konjac glucomannan (KGM), which is a natural polysaccharide, by a one-step hydrothermal method. The resultant GQDs were characterized by various methods such as elemental analysis, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, atomic force microscopy, high-resolution transmission electron microscopy, X-ray diffractometry, and particle size analysis. The photoluminescence properties of the products were evaluated by ultraviolet-visible spectroscopy, Raman spectroscopy, and fluorescence spectrometry. The lowest unoccupied molecular orbital (LUMO) and the highest occupied molecular orbital (HOMO) of the products were calculated and verified by cyclic voltammetry. A cytotoxicity test indicated that the GQDs prepared from KGM had good biocompatibility. Moreover, the GQDs had excellent cell imaging performance, which suggests that the resultant products are promising candidates for biomedicine.

By combining the controllable core/shell strategy with graft copolymerization of polysaccharides, controllable core/shell magnetic molecularly imprinted polymers (MIPs) based on konjac glucomannan for selective recognition and enrichment of trichlorfon were fabricated and evaluated. By varying the dose of the polymeric precursors, the shell thickness of the core/shell structure could be regulated over a wide range. The magnetic nanoparticles encapsulated by polymers still had high magnetic performance and could be easily separated by an external magnetic field. The results of adsorption experiments showed that the MIPs could specifically recognize and adsorb trichlorfon with excellent selectivity, repeatability, and stability. The adsorption isotherm of MIPs could be fitted by the Langmuir equation. In addition, magnetic MIPs have been successfully applied to the detection of trichlorfon in real samples. Eco-friendly MIPs would be particularly suitable for the enrichment and separation of pesticide residues in food samples.

No abstract