几种Fe（Ⅵ）化合物的物理性质、电化学性能及稳定性研究

为深入认识高铁化合物的物理性质和电化学性能,采用化学法合成了K2FeO4、BaFeO4、SrFeO4和 K2Sr(FeO4)2等几种高铁化合物,比较研究了这几种高铁化合物的形貌、结构、在不同浓度KOH溶液中的溶解度 及其放电性能.研究结果显示,在这几种高铁化合物中,BaFeO4具有较好的电化学性能.但在实验过程中发现,除 K2FeO4外,其余几种高铁化合物均不稳定,在干燥环境中放置时会发生分解.采用量子化学从头算方法从理论上 分析了高铁化合物的稳定性变化规律.研究结果表明,高铁化合物的稳定性与阳离子对FeO42-的极化作用有很 大关系,极化作用越强,高铁化合物就越不稳定.     

保健品原料中大豆异黄酮的HPLC法测定

建立了一种同时测定保健品原料中大豆异黄酮6种成分的高效液相色谱测定方法,该方法可以使常见的大豆异黄酮6种主要成分大豆甙、黄豆黄甙、染料木甙、大豆甙元、黄豆黄素、染料木素得以分离和检测.采用甲醇水作流动相,梯度洗脱,Necleosil-C18色谱柱(250mm×4.6mm;5μm),流速为1.0mL/min,紫外检测器,检测波长254nm.结果表明各组分线性关系良好,相关系数(r=0.9872-0.9998),加标回收率在93%-113.6%,相对标准偏差在1.36%-3.89%.该方法简便、准确,可作为同时测定6种大豆异黄酮含量的方法.     

黄酮化合物的偶氮显色反应及其应用研究

在pH 10 4的NH4Cl NH3 ·H2 O缓冲溶液中 ,对磺基氯化重氮苯可与芦丁 ,桑色素 ,染料木甙 ,槲皮素 ,橙皮甙 ,黄岑甙和大豆甙等 7种黄酮化合物发生偶氮显色反应 ,反应产物的最大吸收波长 ,除黄岑甙为 380nm外 ,其余均在 4 30nm ,显色反应的灵敏度依上述顺序逐渐减弱。其中芦丁的摩尔吸收光系数最大 ,为 3 2 8× 10 4L·mol-1·cm-1,大豆甙摩尔吸光系数最小 ,为 8 30× 10 2 L·mol-1·cm-1。提出的分光光度分析方法 ,用于槐米和豆粕中黄酮化合物的测定 ,RSD为 0 2 5 %～ 4 4 8% ,回收率在 99 3%～ 10 5 0 %之间     

电极及电解液对CO_2电化学还原性能的影响

本文采用锡负载多孔扩散电极将CO_2电化学还原为甲酸/甲酸盐,研究催化剂粒径和整平层对CO_2电化学还原性能的影响,并考察了电解液类型、浓度及pH对甲酸产量及电流效率的影响。实验结果表明:采用较小粒径的催化剂且具有整平层的电极可获得较好的CO_2电化学还原性能;KHCO_3溶液较适合作为CO_2电化学还原的电解液;甲酸产量和电流效率随着电解液浓度的增加先升高后降低;采用浓度为0.5mol·L~(-1)、pH为7的KHCO_3溶液时,CO_2电化学还原为甲酸的电流效率最高可达20.7%。     

电化学发光猝灭法测定蜂胶中黄酮总效价

蜂胶具有抗菌、抑制病毒、调节机体免疫力、抵抗类毒素以及清除氧自由基等临床药理作用,其中所含有的黄酮化合物是一类重要的中药药效成分,可有效清除体内自由基。关于蜂胶中黄酮类化合物的测定迄今未见有理想的方法。文章在碘催化的鲁米诺电化学发光的基础上,利用黄酮化合物对碘自由基的清除作用,研究了一种电化学发光猝灭法测定蜂胶中黄酮总效价的分析方法,该方法简便快捷、灵敏度高,可望用于蜂胶产品的质量鉴定。     

雪灵芝中一新甙——马替诺皂甙的NMR研究

从四川雪灵芝中分得一新的Phenylpropanoid Glycoside,Martynoside,经红外,质谱,再采用一维氢谱、碳谱、DEPT谱、旋转坐标NOE差谱和2D远程偶合技术相结合测定该化合物的甙结构.     

STRUCTURAL ANALYSIS OF OLIGOSACCHARIDE CHAIN OF A NEW GLYCOSIDE FROM DIPSOCUS JAPONICUS BY 1D-SEMDY AND ROE DIFFERENCE SPECTROSCOPY TECHNIQUES

从日本续断根部的乙醇提取物中分得一个新的三萜皂苷.经过测定,它为3-O-[βD-吡喃葡萄糖(1→4)］［α-L-吡喃鼠李糖(1→3)]-β-D-吡喃葡萄糖(1→3)-α-L-吡喃鼠李糖(1→2)-α-L-吡喃阿拉伯糖-常春藤甙元.结果表明,采用一维SEMDY和旋转坐标NOE差谱核磁共振新技术相结合的方法测定这一类化合物的糖链结构不需要对化合物进行化学降解或衍生化,方法简便、快速,测定结果可靠,每个糖基的     

聚茜素红-还原态氧化石墨烯修饰玻碳电极测定苯二酚

将还原态氧化石墨烯分散在茜素红水溶液中.通过电化学聚合制备了聚茜素红-还原态氧化石墨烯修饰玻碳电极,用于水中苯二酚含量的测定.电极对于对苯二酚和邻苯二酚的氧化还原反应具有明显的电催化作用.利用示差脉冲伏安法测定了对苯二酚和邻苯二酚的含量,氧化峰电流在7.00×10-6-4.00×10-4mol/L浓度范围内呈良好的线性关系,检出限分别为4.34×10-6、3.42×10-6mol/L.结果表明所制备的修饰电极可应用于水中笨二酚的测定.     

基于喹啉基的噁二唑酮类荧光探针合成及对Fe^(3+)的识别EI北大核心CSCD

以8-氨基喹啉为原料通过重氮化、还原、酰化等反应制备了3种新的喹啉基酰肼化合物1~3,并以其为原料与三光气发生环合反应进一步制备了3种噁二唑酮类化合物4~6。6种新的化合物结构均采用红外光谱、核磁共振谱和质谱等技术以及理论计算进行了深入分析。同时通过热重和荧光光谱等手段对化合物的热学和光学性质进行了测试和分析。结果表明,合成的6种化合物都具有良好的热稳定性,且具有较强的固体荧光发射性能。其中,化合物4~6可作为荧光探针对Fe离子具有高选择性和灵敏性的检测能力,其检出限分别为8.70×10^(-6),1.64×10^(-6),1.01×10^(-6)mol/L。此外,通过理论计算对6种化合物的发光原理也进行了深入分析。     

荧光分光光度法测定黄芪口服液中黄芪甲甙的研究

利用在硫酸条件下香草醛与黄芪甲甙的荧光反应测定黄芪口服液中的黄芪甲甙，黄芪甲甙与香草醛反应产物的最大激发波长为λｅｘ＝３６８ｎｍ，最大发射波长λｅｍ４３５ｎｍ。黄芪甲甙在０．０－３０．０ｍｇ／Ｌ范围呈良好的线性关系，最低检出限为０．３μｇ／ｍＬ，测定样品的回收率为９６．７２％－１０３．３０％。     

Ultrasonic intensification of ozone and electrochemical destruction of 1,3-dinitrobenzene and 2,4-dinitrotoluene

The removal of nitroaromatics from polluted water is difficult due to their high stability to conventional treatment methods. This paper presents a method for the destruction of 1,3-dinitrobenzene and 2,4-dinitrotoluene in aqueous solutions. The compounds are shown to be stable to reaction with ozone, even under ultrasonic activation. The use of ultrasound enhances the rate of electrochemical reduction but the overall rate of reaction is still slow. However, the simultaneous application of ultrasound and ozonation to the electrochemical reaction allows virtually complete destruction of the compounds in short times. The effect is attributed to the ultrasonic enhancement of the electrochemical process giving intermediates that are susceptible to ozone oxidation. While further analytical work is needed to deduce the exact contributions of the various possible degradation mechanisms, the work demonstrates the synergies that can be gained by using combined techniques for the destruction of these difficult compounds.     

Electrochemical reduction of 3‐phenyl‐1,2‐benzisoxazole 2‐oxide on boron‐doped diamond

The bioreduction of N‐oxide compounds is the basis for the mode of action of a number of biologically active molecules. These compounds are thought to act by forming a reactive oxygen species through an intracellular reduction and subsequent redox cycling process within the organism. With these results in mind, the preliminary investigation into the electrochemical reduction of the benzisoxazole 2‐oxide ring system was undertaken, with the thought that this class of compounds would reduce in a similar fashion to other N‐oxide heterocycles. The electrochemical reduction of 3‐phenyl‐1,2‐benzisoxazole 2‐oxide on boron‐doped diamond was studied using cyclic and square wave voltammetry as well as controlled potential electrolysis and HPLC for qualitative identification of the reaction products. It was found that the reduction proceeded with an initial quasi‐reversible one‐electron reduction followed by the very fast cleavage of either the endocyclic or exocyclic N–O bond. Subsequent electron transfer and protonation resulted in an overall two‐electron reduction and formation of the 2‐hydroxyaryl oxime and benzisoxazole. These results are analogous to those observed in the electrochemical reduction of other heterocyclic N‐oxides albeit the reduction of the benzisoxazole N‐oxides takes place at a more negative potential. However, these encouraging results warrant further investigation into the reduction potential of substituted benzisoxazole N‐oxides as well as to elucidate and characterize the nature of the intermediate species involved. Copyright © 2014 John Wiley & Sons, Ltd.     

荧光探针法研究10种中药多糖及黄酮对DNA的保护作用

初步研究了金银花、灵芝等10种中草药多糖和黄酮类化合物对DNA的保护作用。利用溴化乙锭(EB)作为荧光探针,测定金银花、灵芝等10种中药多糖和黄酮类化合物存在下DNA与EB混合液的荧光积分强度,并把不同药物与DNA相互作用定义为作用常数D,D值越大,药物与DNA作用越强,反之越差。根据D的大小讨论了多糖及黄酮类化合物的存在下对DNA保护作用的影响。结果表明,10种中药均能与DNA相互作用,但作用程度不同。多糖提取物存在下它们的作用强弱顺序为：沙棘＞知母＞刺五加＞灵芝＞牛膝＞枸杞＞金银花＞苍术＞黄芪＞菊花。黄酮提取物存在下它们的作用强弱顺序为：沙棘＞金银花＞槲皮素＞枸杞＞苍术＞黄芪＞知母＞刺五加＞灵芝＞牛膝。     

Synthesis,characterization, and electrochemical studies of new 5‐ and 6‐nitro N‐acyl‐1H‐indazoles

Two series of new N‐1 acylindazoles containing 5‐ or 6‐nitro groups were synthesized with moderate to good yields and characterized by IR and NMR spectroscopy. Cyclic voltammetry in aprotic media was utilized for the electrochemical characterization of the compounds. The calculated reduction potentials in physiological conditions are similar to those of known commercial antichagasic drugs. Therefore, the novel series reported herein are prospective candidates for antichagasic biological evaluation. Theoretical calculation results indicate that the studied dinitro derivatives undergo a single step reduction process because of the energy proximity of their radical and anionic state. Copyright © 2011 John Wiley & Sons, Ltd.     

A preliminary investigation upon the electrochemical behavior of CoO and NiO anodes — comparative study

Among the variety of alternate anode materials being studied, the research on the exploration of 3d-metal oxide anodes gains paramount importance in the recent time, as it is bestowed with an easy preparation method and a less complicated decomposition mechanism. Towards this direction, an attempt to synthesize the compound CoO and to investigate the electrochemical behavior of the same both individually and in comparison with NiO compounds was made with a view to understand the extent to which the chosen candidates, viz., CoO and NiO can be exploited as high capacity anodes. Between the two oxides, CoO exhibited a specific capacity of at least 550 mAh/g, against NiO with an average capacity of ∼330 mAh/g. Also, the magnitude of irreversible capacity loss and the extent of capacity fade upon cycling corresponding to CoO anode were found to be lesser than NiO anodes. The enhanced specific capacity values and the better cycleability properties of CoO anodes are believed to be due to the inherent electrochemical characteristics of the compound. The type and the nature of SEI formed over the electrode surface and the formation of possible progressive agglomeration of the products of decomposition are expected to be the factors responsible for the difference in the electrochemical behavior of CoO and NiO anodes. In short, electrochemical characterization of the individual oxides are studied and probable reasons for the observed difference in the charge-discharge behavior of CoO and NiO anodes are discussed in this communication.     

3,3‘,5,5’—四甲基联苯胺——β—环糊精包合物的紫外—可见光谱和电？…

本文采用紫外－可见光谱和电化学的方法研究了３,３’,５,５’－四甲基联苯胺（ＴＭＢ）和β－环糊精形成超分子包合物后的氧化还原性质,研究结果表明在形成包合物后ＴＭＢ的氧化还原特性更好,尤其是在有酶参与时更易被氧化。在包合物内的氧化产物组分更单纯,修饰在电极表面也表现出更好的氧化还原活性。     

Silica surface modification using different aliphatic chain length silane coupling agents and their effects on silica agglomerate size and processability

Silica surface was treated with various aliphatic chain length silane coupling agents and compounded in EPDM using an internal mixer, and their agglomerate sizes, viscosity, and extrudate swell were investigated. The treated silica compounds showed smaller agglomerate size, lower viscosity, and lower swell reduction compared to untreated silica compound after equivalent mixing times. Short chain silane treated silica compound exhibited smallest agglomerate size. Silane acted as dispersing agents and processing aids in silica/EPDM compounds.     

Redox-Switchable New Phthalocyanines Containing Hydrazono-Thiazole-Carboxylate Fragments: Synthesis,Electrochemical, Spectroelectrochemical and Electrocolorimetric Investigation

New phthalonitrile compound with Schiff base, carbothioamide and thiazole moieties as substituents and its corresponding metal-free and metallophthalocyanines (Zn(II), Ni(II), Co(II), and Cu(II)) were synthesized and characterized for the first time. The solubilities of these novel phthalocyanines were high in organic solvents. The redox properties of the compounds have been researched by cyclic voltammetry, square wave voltammetry, controlled-potential coulometry and in situ spectroelectrochemistry in dimethylsulfoxide. The compounds displayed metal and/or phthalocyanine ring-based, generally reversible or quasi-reversible reduction and oxidation processes. The effect of aggregation on the redox behavior of these complexes was also discussed. In general, decreased intensity and broadening in the main Q absorption band and the appearance of a new blue-shifted band confirmed the presence of H-type aggregates in the solutions of the complexes 4, 6 and 8 in DMSO/TBAP. The color changes associated with the redox processes and electrogenerated anionic and cationic redox species were also recorded with in situ electrocolorimetric measurements. In situ UV–vis spectral and associated color changes monitored during the reduction processes of the complexes suggested their applicability in the fields of the electrochemical technologies.