OMS-2/堇青石整体式催化剂的制备及其对二甲醚燃烧的催化性能

 以有机物为粘合剂, 采用涂覆法制备了氧化锰八面体分子筛 (OMS-2)/堇青石整体式催化剂, 采用热重-差热分析、扫描电镜、X 射线衍射、H2 程序升温还原和 O2 程序升温脱附等技术对催化剂进行了表征, 考察了有机粘合剂种类及其用量对二甲醚 (DME) 催化燃烧性能的影响. 结果表明, 在有机粘合剂聚乙烯醇 1799 (其质量含量为 3%) 的作用下, OMS-2 以相互交织的簇体均匀分布于堇青石表面, 且粘附力较强, 制备的整体式催化剂在 DME 催化燃烧中表现出最优的催化性能, 起燃温度 T10 = 169 oC, 完全转化温度 T90 = 243 oC; 催化剂使用后再经高温焙烧其活性仍能保持稳定, 表现出较高的重复使用性.     

Graphene quantum dots combined with copper(II) ions as a fluorescent probe for turn-on detection of sulfide ions

A fluorescent probe for the sensitive and selective determination of sulfide ions is presented. It is based on the use of graphene quantum dots (GQDs) which emit strong and stable blue fluorescence even at high ionic strength. Copper(II) ions cause aggregation of the GQDs and thereby quench fluorescence. The GQDs-Cu(II) aggregates can be dissociated by adding sulfide ions, and this results in fluorescence turn on. The change of fluorescence intensity is proportional to the concentration of sulfide ions. Under optimal conditions, the increase in fluorescence intensity on addition of sulfide ions is linearly related (r ² = 0.9943) to the concentration of sulfide ions in the range from 0.20 to 20 μM, and the limit of detection is 0.10 μM (at 3 σ/s). The fluorescent probe is highly selective for sulfide ions over some potentially interfering ions. The method was successfully applied to the determination of sulfide ions in real water samples and gave recoveries between 103.0 and 113.0 %.

Graphene quantum dots (GQDs) emit strong blue fluorescence which, however, is quenched by copper(II) ions due to the formation of GQDs-Cu(II) aggregates. Fluorescence is recovered by sulfide ions due to the dissociation of GQDs-Cu(II) aggregates.

     

A biosensor prepared by co-entrapment of a glucose oxidase and a carbon nanotube within an electrochemically deposited redox polymer multilayer

A glucose biosensor based on a nanocomposite made by layer-by-layer electrodeposition of the redox polymer into a multilayer containing glucose oxidase (GOx) and single-walled carbon nanotubes (SWCNT) on a screen-printed carbon electrode (SPCE) surface was developed. The objectives of the electrodeposition of redox polymer are to stabilize further the multilayer using a coordinative cross-linked redox polymer and to wire the GOx. The electrochemistry of the layer-by-layer assembly of the GOx/SWCNT/redox polymer nanocomposite was followed by cyclic voltammetry. The resultant biosensor provided stable and reproducible electrocatalytic responses to glucose, and the electrocatalytic current for glucose oxidation was enhanced with an increase in the number of layers. The biosensor displayed a linear range from 0.5 to 6.0mM, a sensitivity of 16.4μA/(mMcm(2)), and a response time of about 5s. It shows no response to 0.05mM of ascorbic acid, 0.32mM of uric acid and 0.20mM of acetaminophen using a Nafion membrane covering the nanocomposite-modified electrode surface.     

两例LnⅢ3配合物的构筑、晶体结构及生物活性

利用多齿席夫碱配体H₂L(H₂L=(E)-6-(羟甲基)-N′-((6-甲氧基吡啶-2-基)亚甲基)吡啶酰肼)与Ln(dbm)₃·2H₂O反应,通过溶剂热法,设计与构筑了 2例新的三核稀土配合物[Ln₃(dbm)₅(L)₂(CH₃OH)₂]·CH₂Cl₂,其中 Ln=Pr (1)、Ho (2),Hdbm=二苯甲酰甲烷。单晶 X射线衍射分析表明：配合物 1与 2同构,其结构由 3个 Ln(Ⅲ)离子、5个二苯甲酰甲烷阴离子(dbm^-)、2个席夫碱配体 L^2-、2个配位的 CH₃OH及 1个结晶 CH₂Cl₂分子组成。3个中心 Ln(Ⅲ)离子通过 4个 μ₂-O原子相互连接,形成折线形的 Ln₃核。生物活性研究表明,配体H₂L、Ln(dbm)₃·2H₂O及配合物1和2均具有较好的抑菌活性。与配体H₂L及Ln(dbm)₃·2H₂O相比较,稀土配合物具有更强的抑菌活性。此外,采用紫外光谱法、循环伏安法和荧光光谱法研究了配合物1和2与小牛胸腺DNA(ctDNA)之间的相互作用,结果表明配合物主要以插入键合的方式与ctDNA结合。     

Analysis of Components and Properties of Extractives from Alnus cremastogyne Pods from Different Provenances

Chemical components with anti-oxidant, anti-inflammatory, and anti-cancer properties extracted from Alnus bark and leaves have been extensively studied. However, less attention has been paid to extractives from Alnus pods, which are mostly treated as waste. Here, extractives of Alnus cremastogyne pods from 12 provenances in Sichuan Province were studied for high value-added utilization of Alnus waste. The extractives were analyzed by Gas Chromatography-Mass Spectrometer (GC-MS), Ultraviolet-visible spectroscopy (UV-Vis spectra), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity. A total of 58, 49, and 51 chemical components were found when the organic solvents of ethanol, petroleum ether, and ethyl acetate were used to collect extractives, respectively. These chemical components including Phytol, CIS-5,8,11,14,17-eicosapentaenoic acid, Germacrene D, Lupeol, and β-sitosterol, etc., have wide applications in the fields of pharmacy and cosmetics. Moreover, it was also found that extractives in ethanol and ethyl acetate had impressive UV resistance, especially for UV-C and UV-B blocking. The results showed that the maximum block ratio towards UV-C and UV-B could reach 99%. In addition, the ethanol extract showed good anti-oxidant activity with a maximum free radical scavenging rate of 96.19%. This comprehensive and systematic study on extractives from Alnus cremastogyne pods promotes the development of high-value utilization of Alnus components.     

Colorimetric detection of kanamycin based on analyte-protected silver nanoparticles and aptamer-selective sensing mechanism

In this work, a novel colorimetric detection method for kanamycin (Kana), a widely used aminoglycoside antibiotic, has been developed using unmodified silver nanoparticles (AgNPs) as sensing probe. The method is designed based on the finding that the analyte (Kana) can protect AgNPs against salt-induced aggregation, and nucleic acid aptamers can decrease the risk of false positives through an aptamer-selective sensing mechanism. By use of the proposed method, selective quantification of Kana can be achieved over the concentration range from 0.05 to 0.6 μg mL⁻¹ within 20 min. The detection limit is estimated to be 2.6 ng mL⁻¹, which is much lower than the allowed maximum residue limit. Further studies also demonstrate the applicability of the proposed method in milk samples, revealing that the method may possess enormous potential for practical detection of Kana in the future.     

金属有机骨架材料MIL-101及其改性材料去除环境污染物的研究进展

目前我国水环境以及空气面临着严峻的污染形势,许多危害人身体健康的污染物亟待治理。 金属有机骨架作为目前新兴的多孔材料,具有高孔隙率、高比表面积、结构可调性以及不饱和金属位点等特点。 这使得金属有机骨架材料具有一定的环境污染物去除能力。 围绕对苯二甲酸铬金属有机骨架材料(MIL-101)及其功能化修饰的改性材料的结构信息展开,总结了材料的主要合成方法,对功能化修饰的方法和原理进行分析,重点分析了这种材料在环境污染物去除等方面的应用研究进展,包括它在重金属离子、农药、抗生素、有机染料、碘离子等污染物的吸附处理领域的应用, 以及在污染物的监测和环境风险预警方面的应用潜力。 指出了材料在制备成本、反复利用次数、污染物后续处理等方面仍然存在的问题。