Effects of preparation conditions of Au/FeO_x /Al_2O_3 catalysts prepared by a modified two-step method on the stability for CO oxidation

Composite oxide FeO x /Al 2 O 3 -supported gold catalysts were prepared by a modified two-step method. The effects of preparation conditions on the initial catalytic activity and long-time stability were studied for CO oxidation. XRD, XPS and in situ FTIR were employed to investigate the state of FeO x and the species on the catalyst surface. The results showed that Au/FeO x /Al 2 O 3 catalysts prepared by this method exhibited high activity and high stability in a wide pH value range. Calcination pretreatm...     

Lectin Conjugated Gold Nanoparticle-based Colorimetric Assay for Studying the Interactions of Antibiotic with Living Cell

The interactions of antibiotic with living cells were studied by lectin conjugated gold nanoparticles(GNPs) based colorimetric assay. Because of the high affinity of lectin for saccharides, the lectin conjugated GNPs are able to employ as indicators for monitoring the antibiotic induced changes of glycosyl complexes. The interactions of a well known antibiotic, tunicamycin, with two different cell lines, HeLa and SHG-44, were selected to establish this assay. In the presence of tunicamycin, the dose- and ti...     

EPR Effect of Amphiphilic Copolymer Micelles Observed by Fluorescent Imaging

Enhanced permeation and retention(EPR) targeting effect of rhodamine B labeled PEG-b-P(LA-co-DHP) [PEG:poly(ethylene glycol);LA:L-lactide;DHP:2,2-dihydroxylmethyl-propylene carbonate] micelles(RhB-micelles) was observed in H22 liver cancer bearing mice.The RhB-micelles were prepared by conjugating rhodamine B with the DHP units of amphiphilic block copolymer PEG-b-P(LA-co-DHP) followed by subsequent self-assembling of the conjugate.The parent copolymer PEG-b-P(LA-co-DHP) was synthesized by ring-opening copo...     

Glucose oxidase as a blocking agent-based signal amplification strategy for the fabrication of label-free amperometric immunosensors

An effective electrochemical signal amplification strategy based on enzyme membrane modification and redox probe immobilization was proposed to construct an amperometric immunosensor.L-cysteine@ferrocene functionalized chitosan,which possessed not only efficient redox-activity but also excellent film-forming ability,was coated on the bare glass carbon electrode. Moreover,the thiol groups(SH)in the ferrocenyl compound were used for gold nanoparticles immobilization via the strong bonding interaction,which co...     

Recent progress in the application of microfluidic systems and gold nanoparticles in immunoassays

Immunoassays are useful for many bioassays. Many new techniques and materials are introduced into the immunoassay to improve the efficiency. This paper reviews recent progress in the application of microfluidic systems and gold nanoparticles in immunoassay. The micro/nano technologies and materials can offer good sensitivity, fast detection, cost-effectiveness and easy signal readout. In particular, the miniaturization of microfluidics and colorimetric assays based on gold nanoparticles have dramatically im...     

参加国家金标准物质定值测试工作的研究报告

近20年来,武警黄金指挥部测试中心参加了12个国家矿石金、12个国家痕量金分析标准物质定值测试工作.该文对取样量、样品均匀性检验、样品焙烧、分析方法的选取、样品稳定性检验等技术进行了总结,并对今后金标准物质的研制提出了建议.     

Quantum dot-based "turn-on" fluorescent probe for detection of zinc and cadmium ions in aqueous media

Health or environmental issue caused by abnormal level of metal ions like Zn²⁺ or Cd²⁺ is a worldwide concern. Developing an inexpensive and facile detection method for Zn²⁺ and Cd²⁺ is in urgent demand. Due to their super optical properties, fluorescent quantum dots (QDs) have been developed as a promising alternative for organic dyes in fluorescence analysis. In this study, a CdTe QDs-based sensitive and selective probe for Zn²⁺ and Cd²⁺ in aqueous media was reported. The proposed probe worked in fluorescence “turn-on” mode. The initial bright fluorescence of CdTe QDs was effectively quenched by sulfur anions (S²⁻). The presence of Zn²⁺ (or Cd²⁺) can “turn-on” the weak fluorescence of QDs quenched by S²⁻ due to the formation of ZnS (or CdS) passivation shell. Under optimal conditions, a good linear relationship between the fluorescence response and concentration of Zn²⁺ (or Cd²⁺) could be obtained in the range from 1.6 to 35 μM (1.3–25 μM for Cd²⁺). The limit of detection (LOD) for Zn²⁺ and Cd²⁺ were found to be 1.2 and 0.5 μM, respectively. Furthermore, the present probe exhibited a high selectivity for Zn²⁺ and Cd²⁺ over other metal ions and was successfully used in the detection of Zn²⁺ or Cd²⁺ in real water samples.     

Library-friendly synthesis of fluorinated ketones through functionalized hydration of alkynes and investigation of the reaction mechanism

A library-friendly synthesis of α-substituted-α-fluoroketones through functionalized hydration of alkynes in one pot under mild conditions is reported. The ready availability of alkynes and organoboronic acids makes this reaction quite attractive. We also studied the key intermediate—a fluorinated cationic gold species—using in situ NMR spectroscopy and ESI-high resolution mass spectrometry.     

Density functional study of AgnPd and AgnPdH clusters

Small Ag_nPd (n = 5) clusters and their hydrides Ag_nPdH (n = 5) have been studied by density functional theory calculations. For bare clusters, the structures in which the Pd atom has a maximum number of neighboring Ag atoms tend to be energetically favorable. Hydrogen prefers binding to Ag? Pd bridge site of Ag_nPd clusters except for Ag₅Pd. The binding energy has a strong odd–even oscillation. The electron transfers are from Ag atoms to Pd in bare clusters and are from metal clusters to H in cluster hydrides. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011