| Chemiluminescence analysis has important applications in many fields, such as biological engineering, food analysis, environmental monitoring, pharmaceutical analysis and clinical diagnosis. Because its advantage of reaction sensitiveness, wide linear range and fast testing speed. Luminlol have advantage of simply chemical structure, character stability and environmental friendliness, thus often be mixed with H2O2 to form chemiluminescence system. However, their reaction rate is very low, some metal ions and nanoparticles are often used in the system to accelerate the reaction. Layered double hydroxide(LDHs) has large specific surface and basic group, and has certain sensitizing effect to luminol- H2O2 chemiluminescence system. But former researches only focused on the LDHs interlayer anion, ignored the metal cations in the basic sheet, and the synergy effect of LDHs sheet with nanoparticles. Ag supported LDHs and a series of doped LDHs(doped with Cr3+、Co2+ and Cu2+) were synthesized and their catalytic action to luminol-H2O2 chemiluminescence system were studied. The main contents and conclusions are as follows:1 The Mg-Al-LDHs precursors was synthesized by co-precipitation method, then silver nanoparticles was supported on Mg-Al-LDHs sheet by in situ redox precipitation. The gained sample was characterized by X-ray diffraction(XRD), Transmission electron microscope(TEM). The traditional flow injection analysis(FIA) method was introduced to assess the catalysis effect of gained sample to luminol-H2O2 chemiluminescence(CL) system. The results showed that the synthetical nanocatalyst has the similar sheet structure as LDHs and well catalytic activity to luminol-H2O2 chemiluminescence system. Several factors such as Na OH concentration, luminol and LDHs-Ag concentration, were designed to optimize the catalytic conditions of luminol- H2O2-LDHs-Ag mixed system. The optimal condition was Na OH concentration at 0.05mol/L, luminol concentration at 2×10-4mol/L and LDH for 2g/L. Under the optimal conditions, the chemiluminescence intensity(I) of luminol-H2O2-LDHs-Ag systems had a linear relationship with the concentration of H2O2(within 1×10-5 to 1×10-3 mol/L): I = 22.24+ 5289.22 c(× 103 mol/L), the correlation coefficient R2 of the equation was 0.9965, detection limit was 7.7×10-6 mol/L(S/N=3). Therefore, this method has certain research value and can be used for quantitative analysis of microscale H2O2.2 Cr-Mg-Al- layered double hydroxides(LDHs) was synthesized by co-precipitation method, and its hydrotalcite- like crystal structure and hexagonal lamellar appearance was confirmed by Fourier transform infrared spectroscopy(FTIR), X-Ray power diffraction(XRD) and transmission electron microscopy(TEM), respectively. The results showd that doping of Cr3+ had no effect on the LDHs layered structure, just reduced the crystallinity of LDHs. The traditional flow injection analysis(FIA) method was introduced to assess the catalysis effect of sample to luminol-H2O2 chemiluminescence(CL) system. Under the optimal conditions at p H 11, luminol concentration at 2×10-4 mol/L and LDHs for 2 g/L, the chemiluminescence intensity(I) of luminol-H2O2-Cr-Mg-Al-LDHs systems had a linear relationship with the concentration of H2O2(within the range of 1×10-5 to 1×10-3 mol/L): I =-101.80+ 203.57c(× 105 mol/L)(R2 =0.9918), detection limit was 7.5×10-6 mol/L(S/N=3).3 Co-Mg-Al-LDHs was synthesized by co-precipitation method and characterized by Fourier transform infrared spectroscopy(FTIR), X-ray diffraction(XRD), Transmission electron microscope(TEM). The results showd that the doping of Co2+ had no effect on the physical properties of LDHs. Flow injection analysis(FIA) method was introduced to assess the catalysis effect of sample to luminol-H2O2 chemiluminescence(CL) system. Researches showd that Co2+ can greatly improve the catalytic performance of LDHs materials, and the effect was increased with the content of Co2+. The optimal condition was at p H 11, luminol concentration at 2×10-4 mol/L and LDHs for 2 g/L. Under the optimal conditions, the chemiluminescence intensity(I) of luminol- H2O2-Co-Mg-Al-LDHs systems had a linear relationship with the concentration of H2O2(within 1×10-6 to 1×10-3 mol/L): I =-231.53+ 894.83c(× 106 mol/L)(R2=0.9954), detection limit was 3.2×10-7 mol/L(S/N=3).4 Cu-Mg-Al- LDHs was synthesized by co-precipitation method and characterized by Fourier transform infrared spectroscopy(FTIR), X-ray diffraction(XRD), Transmission electron microscope(TEM). Flow injection analysis(FIA) method was introduced to assess the catalysis effect of sample to luminol-H2O2 chemiluminescence(CL) system, and the optimal condition was at p H 11, luminol concentration at 2×10-4 mol/L and LDHs for 2 g/L. Under the optimal conditions, the chemiluminescence intensity(I) of luminol-H2O2-Cu-Mg-Al- LDHs systems had a linear relationship with the concentration of H2O2(within 1×10-6 to 1×10-4 mol/L): I =- 422.85+ 230.30 c(× 106 mol/L)(R2=0.9998), detection limit at 3.8×10-7 mol/L(S/N=3). Resorcinol could strongly inhibit the chemiluminescence intensity of luminol- H2O2-Cu-Mg-Al-LDH. The intensity of luminol- H2O2-Cu-Mg-Al-LDHs was linear with the concentration of resorcinol(within 1×10-9 to 1×10-3 g/L concentration range) as I=3772-303.14 lgc, with correlation coefficient R2=0.9972 and detection limit at 3.7×10-10 g/L(S/N=3). The luminol-H2O2 chemiluminescence system catalyzed by C u-Mg-Al- LDH used in this st udy has t he advanta ges of si mple process, l ow cost, wide linear r a nge a nd lo w detecti on li mit, t hus this met hod ca n be used in t he trace detection of resorcinol. |
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