多功能Zn(Ⅱ)金属有机骨架荧光传感器检测苯甲醛、四环素、2,4,6-三硝基苯甲酸、氟啶胺、Cr2O72-和Fe3+

成功制备了新型 Zn(Ⅱ)金属有机骨架(MOF)[Zn₂(Hdepa)(dya)₂]n (1)(H₅depa=2,2'',3,4'',5-二苯醚五羧酸,dya=2,2''-二吡啶胺)。单晶 X 射线衍射分析表明 MOF 1 由 2 个 Zn²⁺离子与 1 个 Hdepa^4-离子和 2 个 dya 分子连接组成,通过氢键形成三维骨架。用粉末X射线衍射和IR表征了配合物1的相纯度。值得注意的是,配合物1具有优异的荧光特性和热稳定性,1的高灵敏度和选择性使其能够作为荧光传感器检测苯甲醛(BZH)、四环素(TC)、2,4,6-三硝基苯酚(TNP)、氟啶胺(Flu)、Cr₂O₇^2-和Fe³⁺。此外,通过荧光寿命分析了Fe³⁺、TC、BZH对MOF 1的荧光的猝灭过程,通过能量转移研究了Fe³⁺、Cr₂O₇^2-、TNP、TC、BZH和Flu的荧光猝灭机理。     

叔丁基亚胺四氯合钽(V)阴离子配合物[IPrH]+[tBuN=TaCl4(py)]-的合成与表征

[^tBuN=TaCl₃(py)₂]和氮杂环卡宾(IPr =1,3-bis(2,6-diisoproylphenyl)imidazol-2-ylidene)的反应得到预料之外的叔丁基亚胺四氯合钽(V)离子配合物[IPrH]⁺[^tBuN=TaCl₄(py)]- (1)。利用核磁共振波谱,红外吸收光谱,荧光光谱,元素分析和X-Ray单晶衍射对配合物1的结构进行了表征。X-射线单晶衍射分析表明,Ta(V)中心与4四个氯和2个分别来自亚胺和吡啶配体的氮原子以八面体构型配位。     

载银二氧化钛纳米管表面pH敏感膜构建及其抑菌特性

采用表面涂覆硅烷偶联剂KH550、两步光接枝、阳极氧化等方法,在钛表面成功制备出一种pH型敏感膜覆盖的载银二氧化钛（TiO₂）纳米管阵列。利用扫描电镜（SEM）、透射电镜（TEM）、能谱分析（EDS）、原子吸收光谱（AAS）对该pH敏感膜覆盖的载银TiO₂纳米管阵列理化性能进行了表征,采用抑菌环实验定性考察了样品的抗菌特性,并计算其抑菌率。结果表明,含银离子溶液在毛细管力作用下大量进入TiO₂纳米管中,并在pH型敏感膜的调控下,使银离子在不同pH环境下具备不同的释放行为,从而达到良好的控释效果;载银TiO₂纳米管的抑菌率与银离子负载量成正比,且抗菌性能持久。     

High efficiency palladium catalysts supported on multi-wall carbon nanotubes synthesized with 1,3-bis(diphenylphosphino) propane for ethanol oxidation

In this paper, a facile and effective method is introduced to prepare palladium electrocatalysts for the oxidation of ethanol in alkaline media. According to the transmission electron microscopy measurement, the as-prepared Pd nanoparticles with the average particle size of 2.5 nm are evenly deposited on the surface of the multi-wall carbon nanotubes by using 1,3-bis(diphenylphosphino) propane as a special additive. Electrochemical measurements demonstrate that the as-prepared catalyst exhibits good electrocatalytic activity and stability for the electrooxidation of ethanol.     

量子点敏化太阳电池

基于量子限域效应的新型太阳电池——量子点敏化太阳电池(QD-SSCs),由于其最大理论转化效率超过了传统的Shockley-Queisser极限效率,已经成为目前最具研究潜力的太阳电池之一。本文综述了近几年来QD-SSCs领域的研究进展,主要从半导体氧化物纳米材料,特别是其低维纳米结构下的特殊性能;金属硫族化合物纳米晶;电解质;对电极等几个方面评述了电池材料的研究进展。另外,从量子点材料的制备和组装方面简述了目前电池光阳极的研究情况,并介绍了提高量子点光敏化性能的几个新途径。最后,从开路电压和短路电流角度分析了影响电池性能的几个关键因素,并对QD-SSCs今后的发展进行了展望。     

A Hairpin Electrochemical Aptasensor for Sensitive and Specific Detection of Thrombin Based on Homogenous Target Recognition

An electrochemical aptasensor was developed for sensitive and specific detection of thrombin by combining homogenous recognition strategy and gold nanoparticles (AuNPs) amplification. Streptavidin‐alkaline phosphatase was used as reporter molecule. Compared with the traditional hairpin aptasensor monitoring the distance of the redox molecule from the electrode surface, the proposed aptasensor successfully overcome the limitations of distance and improved the stability and high affinity of the aptamer hairpin through homogenous recognition, which enhanced the sensitivity and selectivity of the sensors effectively. Additionally, AuNPs were employed to increase the active area and conductivity of the electrode, thus, improving the sensitivity of the aptasensor. As a result, the designed thrombin detection sensor obtained a lower detection limit of 0.52 pM in buffer and 6.9 pM in blood serum.     

Electrochemical Recognition of Chiral Molecules with Poly(4‐bromoaniline) Modified Gold Electrode

A poly(4‐bromoaniline) (PBA) film is electrochemically synthesized on a gold electrode for the recognition of amino acids enantiomers. Scanning electron microscopy measurements show that the porous PBA films are made up of nano‐ribbons. At the PBA modified Au electrode differential pulse voltammograms of L ‐ and D ‐glutamic acids not only have very different current densities, but also produce different waveforms, providing an intuitive way to differentiate the two chiral molecules. Similar results are obtained in analyzing L ‐ and D ‐aspartic acids. Control experiments suggest that the observed sensing behavior arises from synergistic interactions between Au and the PBA film, where polymerization at the meta‐position creates a steric structure needed for differentiating chiral molecules.     

Electrochemical DNA Biosensor Based on Partially Reduced Graphene Oxide Modified Carbon Ionic Liquid Electrode for the Detection of Transgenic Soybean A2704‐12 Gene Sequence

In this work a partially reduced graphene oxide (p‐RGO) modified carbon ionic liquid electrode (CILE) was prepared as the platform to fabricate an electrochemical DNA sensor, which was used for the sensitive detection of target ssDNA sequence related to transgenic soybean A2704‐12 sequence. The CILE was fabricated by using 1‐butylpyridinium hexafluorophosphate as the binder and then p‐RGO was deposited on the surface of CILE by controlling the electroreduction conditions. NH₂ modified ssDNA probe sequences were immobilized on the electrode surface via covalent bonds between the unreduced oxygen groups on the p‐RGO surface and the amine group at the 5′‐end of ssDNA, which was denoted as ssDNA/p‐RGO/CILE and further used to hybridize with the target ssDNA sequence. Methylene blue (MB) was used as electrochemical indicator to monitor the DNA hybridization. The reduction peak current of MB after hybridization was proportional to the concentration of target A2704‐12 ssDNA sequences in the range from 1.0×10^?12 to 1.0×10^?6 mol/L with a detection limit of 2.9×10^?13 mol/L (3σ). The electrochemical DNA biosensor was further used for the detection of PCR products of transgenic soybean with satisfactory results.     

Analytical Properties of Solid-substrate Electrospray Ionization Mass Spectrometry

Conventional electrospray ionization mass spectrometry (ESI-MS) uses a capillary for sample loading and ionization. Along with the development of ambient ionization techniques, ESI-MS using noncapillary emitters has attracted more interest in recent years. Following our recent report on ESI-MS using wooden tips (Anal. Chem. 83, 8201–8207 (2011)), the technique was further investigated and extended in this study. Our results revealed that the wooden tips could serve as a chromatographic column for separation of sample components. Sequential and exhaustive ionization was observed for proteins and salts on wooden tips with salts ionized sooner and proteins later. Nonconductive materials that contain microchannels/pores could be used as tips for ESI-MS analysis with sample solutions loaded to the sharp-ends only, since rapid diffusion of sample solutions by capillary action would enable the tips to become conductive. Tips of inert materials such as bamboo, fabrics, and sponge could be used for sample loading and ionization, while samples such as tissue, mushroom, and bone could form tips to induce ionization for direct analysis with application of a high voltage.