The rare-earth ion doping in nanocrystals has the advantage on improving the interested properties. As one of rare-earths, the trivalent samarium ion (Sm 3 + ) was used as a dopant. The precursor of Sm 3 + -doped cadmium ferrite (CdFe 2 O 4 ) nanocrystals was reacted in water-soluble polymeric nanoreactors as a dispersed phase in miniemulsion, and then calcinated to form doped nanocrystals. The 1% Sm 3 + -doped nanocrystal in small size exhibited the smaller narrow gap energy and weak photoluminescent emission intensity; which attributed to the positive influences on the photocatalytic degradation. The selected Sm 3 + -doped spinel ferrite nanocrystals provide a unique catalyzer for organic compound photodegradation.
Huiwen Xiong,Jingwen Gao,Ying Wang,Ziyi Chen,Miao-Miao Chen,Xiuhua Zhang,Shengfu Wang
In this study, an ultrasensitive electrochemiluminescence (ECL) aptasensor based on Ru(bpy)32+-doped silica nanoparticles (Ru@SiO2 NPs) coupled with gold nanoparticles (Au NPs) was developed for the determination of ractopamine (Rac). TPrA is used as the coreactant, the Ru@SiO2 NPs serve as the ECL luminophores, and the Au NPs work as a catalyzer in the redox reaction as well as the carrier that immobilizes the aptamer. Meanwhile, the complete incorporation of the Ru@SiO2 NPs and Au NPs increases the localized surface plasmon resonance (LSPR) probability, thus promoting ECL emission. The ractopamine (Rac) target molecules are specifically captured on the electrode surface by aptamer recognition. The ECL signal is quenched by energy transfer from the luminophore to benzoquinone compounds, which are oxidative products of Rac from the electrochemical scanning process. The proposed ECL aptasensor exhibits ultrahigh sensitivity and excellent selectivity for Rac detection. The linear response ranged over Rac concentrations from 1.5 × 10−12 M to 1.5 × 10−8 M with a detection limit of 4.1 × 10−14 M (S/N = 3). The detection recovery of Rac in real meat samples confirmed the satisfactory performance of the method. This study describes a versatile ECL aptasensor based on the combined functions of luminous nanospheres and Au NPs, indicating its potential application for the ultrasensitive analysis of targets in diverse systems.
Fluorescein and its derivatives, including 4′,5′–dibromofluorescein, 2′,7′–dichlorofluorescein and 2′,4′,5′,7′–tetrabromofluorescein can be employed as efficient coreactants for luminol reaction. Under an alkaline condition they reacted with luminol to produce measureable chemiluminescence (CL) in the absence of any extra–oxidant. Cobalt ion (Co 2+ ) significantly enhanced the CL emission of the reaction. The CL emission was strongly dependent on the concentration of carbonate buffer used; higher concentration of carbonate buffer provided more intense CL emission. The system had two emission peaks locating at 425 nm and 535 nm, respectively. With 4′,5′–dibromofluorescein as the coreactant for luminol reaction, a new CL method was developed for the detection of Co 2+ . The procedure allowed the linear detection of Co 2+ in the range of 5–1000 nmol/L. The limit of detection (LOD) and limit of quantitation (LOQ) were 1.8 nmol/L and 5.0 nmol/L, respectively. The intra–day precision (n = 11) and inter–day precision (n = 3) was 3.2% and 4.7% for replicated measurements of 0.2 μmol/L Co 2+ solution. The method was successfully applied to the determination of Co 2+ in blue silica gel samples.
危险品化学品经营许可证（带存储）