血红蛋白在裸银电极上的光谱电化学研究

光谱电化学作为把光谱技术和电化学方法有机结合起来的一门新技术［１］,已成为将电化学研究提高到分子水平的强有力手段．多种类型及不同用途的光谱电化学池［２］成功地应用于生物分子的电化学及光谱电化学性质研究［３］．我们利用自制的长光程薄层光透光谱电化学池研...     

Synthetic Studies on Coenzyme Q10

A practical, highly stereoselective ten‐step synthesis of coenzyme Q₁₀ ( 1 ) has been accomplished (overall yield ca. 28%), starting from commercially available 2,3‐dimethoxy‐5‐methylbenzoquinone (Scheme). The introduction of the first side‐chain isoprenyl group with (E)‐configuration (compound 6 ) was realized by means of a coupling reaction of the aromatic system 3 with oxirane, followed by Swern oxidation and Wittig olefination. The tosyl (Ts) group in the sulfone 9 was selectively removed with sodium naphthalenide in THF to afford 1 .     

Investigation of Coenzyme Q10 by Voltammetry

A simple, accurate and rapid voltammetric method has been developed for the quantitative determination of coenzyme Q₁₀. Studies with direct current voltammetry were carried out using a glassy carbon electrode (GCE) in a phosphate buffer solution (pH 6.86). A well-defined oxidation peak of CoQ₁₀ was obtained at -0.600 V vs Ag/AgCl. The magnitude of the oxidation peak current has been found to be related to the concentration of the coenzyme over the range of (2.010^-5 to 2.010^-4 M) (r = 0,991). Antioxidant activity of CoQ₁₀ was investigated.     

Synthetic Studies on Coenzyme Q10. Part 3

An efficient and stereoselective approach to the synthesis of coenzyme Q₁₀ is described (Scheme). The MeOCH₂‐protected p‐hydroquinone 4 containing the C₅ (E)‐allyl (tert‐butyl)dimethylsilyl ether moiety was obtained via a halogen–lithium exchange of the MeOCH₂‐proctected 2‐bromo‐5,6‐dimethoxy‐3‐methylhydroquinone 2 and subsequent addition to (E)‐(^tBuMe₂Si)‐OCH₂C(Me)=CHCH₂Br ( 3 ). The reductive desulfonylation of compound 8 , obtained from 4 via 5 – 7 , was successfully carried out by employing Li/EtNH₂.     

辅酶Q10的合成方法研究进展

介绍了采用侧链直接引入法、侧链延长法和母体与侧链同时增碳法合成辅酶Q10的研究进展。参考文献18篇。     

辅酶Q10及其杂质结构鉴定

辅酶Q10是1975年初次从牛心肌中分离而得的一种脂溶性结晶,属泛醌类化合物.具有提高人体免疫力,增强抗氧化能力,延缓衰老等功能.可用于心血系统疾病、肝病等辅助治疗.近年来,国内外也将辅酶Q10广泛用于营养保健品及食品添加剂.     

Synthetic Studies on Coenzyme Q10. Part 2

An improved route to coenzyme Q₁₀ ( 1 ) starting from commercially available coenzyme Q₁ is described. The key steps in this synthesis are the SeO₂‐mediated oxidation of the protected isoprenylhydroquinone 3 into the (E)‐allyl alcohol 5 without the formation of undesired stereoisomer and the one‐pot reductive elimination of the phenylsulfonyl and dibenzyl groups in 7 by using naphthalenyllithium.     

In-situ FTIR Spectroelectrochemical Study of Chromium Hexacyanoferrate on Glassy Carbon Electrode

CrHCFisanoveltransition-metalcyanometallatecomPound.Asasortofinorganicpolymer,ithasattractedmuchattention.AwiderangeofaPplicationhasbeenfoundl'2.However,consideringthelimitedstudyoftheCrHCFlGCmodifiedelectrodereportedpreviously',thereisstillmuchtodo.Thisletterreportsanin-situFTIRspectroelectrochemicalinvestigationofCrHCFmodifiedonaglassycarbonelectrode(CrHCF/GC).ItwasfoundthatthestructureofCrHCFwasre1ativelyamorPhous,andthelatticeofCrHCFwasdeformedduringtheelectrochemicalredoxpro…     

Electroanalysis of RNA at a Silver Electrode

The behavior of nucleic acids at charged biological interfaces (e.g. membranes) is of great importance in many biological processes. Meanwhile, the electrochemical system serves as a versatile and illuminating model of biological system, which might provide important information on properties and conformation of biomacromolecules. Electrochemical studies on DNA have attracted great interest and contributed a lot to the knowledge of structure-function relationship of DNA. However, up to now, electrochemical researches on RNA were much less explored.     

Galvanostatic Studies on Reduction of Oxygen at Silver Electrode

Galvanostatic studies with low current density in 0.1 N KNO₃ medium reveal that reduction of oxygen at silver electrode is totally irreversible and in the range of oxygen concentration studied, 2.2-306.3×10^?9 mole/cm³, the E-log [0₂] plot consists of two straight lines, one has a slope of 0.12 volts/decade (C>1 ppm up to air-saturated) and the other, 0.72 volts/decade (0.1<C<0.8 ppm). The transfer coefficient, α, the heterogeneous rate constants, k^o_fh and k^o_gh were evaluated to be 0.12, 2.8×10^?4, 1.6×10^?7 for the higher concentration range, and 0.02, 4.4×10^?4 for the lower concentration region respectively. A possible analytical method for tenths ppm level of oxygen is suggested.     

酸性溶液中钯催化醇电化学氧化的研究

应用电化学循环伏安法(CV)和现场红外光谱(FTIR),研究了酸性溶液中钯催化甲醇、乙二醇电氧化的过程.结果表明:在酸性和中性介质中,甲醇和乙二醇在多晶Pd电极上氧化须在1.5V以上才能发生.随着溶液pH值的降低,过电位减小且峰电流密度上升.溶液的pH值以及电极表面形成的吸附含氧物种对Pd电催化氧化醇有显著的影响.现场红外光谱电化学测试显示,在高电位和强酸性介质中,乙二醇在Pd电极上的氧化产物主要是CO2和少量的乙二酸.在酸性和中性介质中,无论在低电位或高电位,甲醇和乙二醇在Pd上氧化的主要产物是CO2,没有发现CO的存在,说明该氧化过程CO2是经过非毒化的路径产生的.     

TLC Identification and Quantification of Coenzyme Q10-β-Cyclodextrin Complex

JPC – Journal of Planar Chromatography – Modern TLC - TLC is often set aside as a result of unjustified simplification of analytical knowledge and, at the same time, over-emphasis of...     

辅酶Q9的合成

以辅酶Q0为起始原料,经Diels-Aider加成,缩合和逆Dicls-Alder分解反应,合成了辅酶Q10的类似物辅酶Q9,总收率61.9%.中间体和Q9的结构经1H NMR和EI-MS表征.     

液相色谱-电化学检测法测定小鼠血浆和组织线粒体中的辅酶Q和维生素E

 建立了同时测定氧化型和还原型辅酶Q以及维生素E的液相色谱 电化学检测方法。样品中氧化型和还原型辅酶Q9和Q10 以及维生素E混合物经过液相色谱分离柱分离 ,在 - 5 5 0mV的电化学调节池中将氧化型辅酶Q还原为还原型 ,再经过 15 0mV分析池将样品中原有的还原型辅酶Q和经过调节池还原的辅酶Q以及维生素E一同氧化。该方法用于小鼠组织线粒体和血浆样品中氧化型和还原型辅酶Q9和Q10 以及维生素E的同时检测 ,灵敏度高 ,选择性好 ,结果令人满意。     

银微盘电极上L-半胱氨酸的伏安行为研究

银微盘电极上Ｌ－半胱氨酸的伏安行为研究方宾,方惠群,陈洪渊（南京大学化学系,南京,２１００９３）关键词银微盘电极,Ｌ－半胱氨酸,循环伏安法由碳纤维、金、铂、铱等材料制成微电极的研究国内、外报道甚多［１～５］,但以银为材料制成的电极在生化物质方面的研究...     

尿嘧啶在银电极表面吸附状态的研究

综合分析了尿嘧啶在银电极表面不同条件的表面增强激光Ｒａｍａｎ光谱（ＳＥＲＳ）,利用扩展的Ｈüｃｋｅｌ分子轨道法（ＥＨＭＯ）对尿嘧啶分子在银电极表面的吸附状态进行了计算．结果表明：最稳定的吸附构型能较成功地阐明尿嘧啶吸附在银表面的ＳＥＲＳ谱;尿嘧啶在银表面主要是以Ｎ（３）去质子化的形式吸附;尿嘧啶在银表面的吸附取向是由其浓度和银表面电位共同决定;在较低浓度和较高电位时,Ｎ（３）去质子化的尿嘧啶离子在银表面主要是通过Ｃ（２）及整个嘧啶环上的π电子体系与银表面的相互作用平躺地吸附;在较高浓度和较低电位时,吸附取向发生改变,即主要是通过Ｎ（３）与Ｏ（１０）以及Ｎ（３）与Ｏ（８）垂直地共同吸附在银表面上     

Anodic Deposition of Iodide Ion at Silver Electrode

Anodic deposition of iodide ion on silver at 25° in aqueous (0.5 M KNO₃) and in 90% (w/w) ethanol-water (0.05 M KClO₄) solutions was studied galvanostatically. The exchange current density, transfer coefficient and the rate constants for the electrode reaction were evaluated. The experimental results revealed that the overall electrode reaction and the charge-transfer step was the same one, i.e., , which might be assumed highly reversible as reflected by the exchange current density (i) and transfer coefficient (α). The numerical values of the rate constants, and at 25° were, in aqueous solution, 1.02×10^?5 and 2.88×10^?6, and in ethanol solution, 2.88×10^?5 and 6.3×10^?6 cm sec^?1, respectively.     

测定人血浆中辅酶Q10的反相高效液相色谱法

用反相高效液相色谱法测定了人血浆中的辅酶Q10，样品用正已烷萃取，甲醇-乙醇（体积比70：30，含20mmol/L LiClO4）为流动相，在Waters μBondapak C18柱上分离并于波长275nm下检测，外标法定量；方法线性范围为10-100ng，r=0.9998，平均回收率为96％，相对标准偏差为3.0％；方法检出限为2ng(质量)和0.2mg/L（质量浓度）。     

Solubility Measurements and Prediction of Coenzyme Q10 Solubility in Different Solvent Systems

The solubility of coenzyme Q10 in ethyl acetate, n-hexane, 1-butanol, 1-propanol, 2-propanol and ethanol in the temperature range 270.15–320.15 K, under atmospheric pressure, was measured by a gravimetric method and compared with the data predicted using the conductor like screening model for realistic solvation (COSMO-RS) method. The results show that the solubilities of coenzyme Q10 in the above solvents increase with temperature. The temperature dependences of predicted solubilities were consistent with the experimental data. The experimental data were correlated with the Apelblat equation. At the same temperature, the order of increasing solubility is ethyl acetate > n-hexane > 1-butanol > 1-propanol > 2-propanol > ethanol.     

半微分阴极溶出伏安法研究硫离子在银电极上的电化学行为

用半微分阴极溶出伏安法研究硫离子在银电极上的电化学行为。在ＮａＯＨ－ＥＤＴＡ－Ｎａ２ＳＯ３底液中，可消除溶解氧及部分重金属离子Ｃｕ２＋，Ｐｂ２＋，Ｚｎ２＋，Ｃｄ２＋和Ｎｉ２＋的干扰。一些阴离子Ｃｌ－，Ｉ－，ＮＯ－３和ＳＯ２－４不干扰。硫离子浓度在３．１９×１０－６ｍｏｌ／Ｌ至３．１３×１０－５ｍｏｌ／Ｌ范围内与溶出峰高成线性关系。对两种人发样品中硫含量测定的回收率分别为９３．９％和９７．８％。