Rapid detection of Escherichia coli by flow injection analysis coupled with amperometric method using an IrO2–Pd chemically modified electrode

An amperometric method for the rapid detection of Escherichia coli (E. coli) by flow injection analysis (FIA) using an IrO₂–Pd chemically modified electrode (CME) was developed in this paper. The method is based on a good marker β-d-galactosidase which was found in E. coli strains. β-d-galactosidase was produced by the induction of isopropyl β-d-thiogalactopyranoside (IPTG) and released from E. coli cells through the permeabilization of both polymyxin B nonapeptide and lysozyme to E. coli cells wall. The released β-d-galactosidase could catalyze the hydrolysis of the substrate p-aminophenyl β-d-galactopyranoside (PAPG) in the culture medium to produce 4-aminophenol which was proportional to the concentration of E. coli. Hence, E. coli could be detected by the determination of 4-aminophenol. An IrO₂–Pd CME, which showed high sensitivity in determination of 4-aminophenol, was prepared as the electro-detector in FIA. The amplified response current of 4-aminophenol obtained at the IrO₂–Pd CME was linear with the concentration of E. coli ranging from 2.0 × 10² to 1.0 × 10⁶ cfu/mL, the detection limit of this method to E. coli was 150 cfu/mL and the complete assay could be performed in 3 h.     

环糊精手性微反应器中苯乙烯的不对称环氧化反应

研究了酮与环糊精手性协同催化作用下,用非手性酮与过氧硫酸氢钾(商品名Oxone)原位产生的二氧杂环丙烷实现了对包合在环糊精手性微反应器中苯乙烯的不对称环氧化反应,考察了α-环糊精、β-环糊精、γ-环糊精与不同的酮协同催化反应效果,并对协同催化反应机理进行了探讨.结果表明,β-环糊精和甲基异丁基酮(MIBK)及Oxone原位形成的二氧杂环丙烷具有较好的协同催化作用;MIBK用量、碳酸氢钠用量、反应时间和温度等因素对反应产物的收率和对映体选择性有一定的影响.在优化条件下,环氧苯乙烷的ee值可达46%.     

肟醚-酰胺衍生物的合成与生物活性研究

为了寻找高效、低毒的新农药,采用活性结构拼接法设计并合成了12个新型肟醚-酰胺类化合物,其结构均经1HNMR、IR、LC/MS及元素分析确证。初步生物活性测定结果显示,部分化合物具有明显的杀菌活性,其中化合物3a和3h在500mg/L的浓度下对小麦白粉病菌的盆栽活性均达80%以上。     

葡萄糖、半乳糖和乙醇恒电流氧化过程电位振荡的EQCM研究

采用电化学石英晶体微天平(EQCM)研究了0.5 mol•L^-1 NaOH水溶液中铂电极上葡萄糖、半乳糖和乙醇恒电流氧化过程中伴随的电位振荡行为. 两个糖体系的电位振荡过程伴随EQCM频率的同步振荡响应, 而乙醇体系中相应的频率响应却非常小；三个体系振荡过程的同步动态电阻响应均很小, 表明振荡过程频率响应主要为质量效应. 虽然葡萄糖和半乳糖结构相似, 电位和频率振荡的幅度相当, 但频率波数和周期明显不同, 表明电位振荡行为对两者呈现良好的分子识别能力. 本文也讨论了相关振荡机理和NaOH浓度效应及碱性介质中铂电极电化学过程, 提出了所形成的铂氧化物主要是PtO₂-3H₂O_ad以及两糖体系振荡过程中糖酸根阴离子伴随着高/低电位在铂电极上吸/脱附的新观点.     

[Cu(PTA)(Phen)2](p-MBA)(H6O)配合物的合成、晶体结构及电化学分析

The crystal structure of the title complex with the stoichiometric formula [Cu(PTA)(Phen)₂](p-MBA)(H₆O) (Phen=1,10-phenanthroline, PTA=terephthalic acid, p-MBA=p-toluic acid) has been determined by single-crystal X-ray diffraction. The crystal (C₄₈H₄₀CuN₄O₁₀, M_r=896.38) belongs to the monoclinic space group C2/c, with the following crystallographic parameters: a=1.778 6(3) nm, b=1.912 5(3) nm, c=1.389 9(2) nm, β=114.686(2)°, V=4.295 7(12) nm³, D_c=1.386 g·cm^-3, Z=4, μ(Mo Kα)=0.574 mm^-1, F(000)=1 860, final GooF=1.019, R=0.054 0, wR=0.148 3 for 2 644 observed reflections (I>2σ(I)). The crystal structure shows that the copper(Ⅱ) ion is coordinated with two oxygen atoms from one terephthalic acid molecule and four nitrogen atoms from two 1,10-phenanthroline molecules, forming a distorted octahedral coordination geometry. The cyclic voltametric behavior of the complex is also reported. CCDC: 298809.     

从氨性柠檬酸溶液中电沉积Ni-Mo的机理研究

含钼大于约27％（质量分数）Ni－Mo合金，具有较高的耐蚀性，特别是在盐酸和硫酸溶液中，其耐蚀性优于SUS304不锈钢［1］．因此，人们对该种合金的电沉积进行了广泛的研究［1－4］．对合金共沉积机理也作了一定的研究．一般认为，钼不能单独进行电沉积，但它可以同铁族元素共沉积［5］．对钼与铁族元素的共沉积机理，人们已提出了几种假设．一般认为［3］，钼可能是多步还原，即六价钼首先被电化学还原成低价钼化合物，而后由吸附在诱导金属（铁族元素）上的原子氢进一步还原成合金中的零价钼，为了进一步弄清Ni－Mo合金的共沉积机理，本…     

Crystal Structure, Thermal Stability and Luminescence of Coordination Polymer [Cd（BBP）（p-PDOA）]n

Hydrothermal reaction of Cd（NO3）2·4H2O with bbp and p-PDOAH2 at 140 ℃ yielded a novel 1D cadmium（Ⅱ） coordination polymer, [Cd（bbp）（p-PDOA）]n （bbp=2,6-bis（benzimidazol-2-yl）pyridine, p-PDOA=p-phenylenedioxydiacetate dianion）, in which CdN3O4 pentagonal bipyramids were linked by p-PDOA ligands in a bis-bidentate mode to construct a zigzag chain with the adjacent Cd…Cd distance of 1.14（1） nm, There exists a 2D supramolecular network linked by π-π stacking with a face-to-face distance of 0.35（1） nm between the 2,6-bis（benzimidazol-2-yl） pyridine ligands and hydrogen-bonding interactions （0.27（4） nm）. A 3D supramolecular network was further constructed by these non-covalent interactions between the zippers. The TG/DTG showed that its chain skeleton was thermally stable up to 389 ℃ and the blue fluorescent emission of the complex was determined at 428 nm in a solid state with its long decay lifetime of 7.24 ns.     

由硅醚经脱保护-氧化-Wittig反应一锅法合成,-不饱和酯

在1摩尔醋酸和稳定的Wittig试剂存在下, 活性MnO₂作为氧化剂时, 硅醚发生脱保护-氧化-Wittig反应. 考查了各种硅醚, 诸如苄基硅醚、炔丙基硅醚、烯丙基硅醚和烷基硅醚等作底物在反应性能方面的差异. 该反应使硅醚直接形成碳碳双键而得到α,β-不饱和酯. 产物的结构经红外光谱、核磁共振谱表征.     

Electrochemical Determination of Ascorbic Acid at γ-MnO<Subscript>2</Subscript> Modified Carbon Black Microelectrodes

A carbon black microelectrode modified by -MnO₂ has been prepared. The electrocatalytical oxidation of ascorbic acid (AA) at this microelectrode was investigated. The 2nd-order linear scan voltammograms of AA are recorded from –0.5 to 0.5V (vs. SCE). The relationship between the oxidation peak current of AA and its concentration in the range of 1.0×10^–64.0×10^–3molL^–1 is linear. The detection limit (3) was found to be 6.0×10^–7molL^–1. Also, the determination of AA in samples is evaluated, and the results are satisfactory.     

二氧化碳促进的醛和酮等羰基化合物烯丙基化反应研究

加入二氧化碳可以促进羰基化合物的烯丙基化反应. 实验结果表明: 在1.0 MPa的二氧化碳和2 equiv.的锡存在下, 以THF/H₂O为反应介质, 芳香醛化合物与烯丙基溴可以顺利地发生烯丙基化反应得到较高的产率, 而芳香酮化合物和脂肪醛等与烯丙基溴反应只得到较低的产率.