催化动力学光度法测定食品中痕量铜

铜是人体内多种酶的活性成分，对人体的新陈代谢有重要的调节作用。人体主要从食物中摄取铜，因此研究测定食品中痕量铜的方法具有实际意义。近年发展起来的催化动力学光度法，对铜的测定非常灵敏。研究发现，在硝酸介质中痕量铜对过氧化氢氧化甲基紫褪色反应有显著的催化作用。本文建立了动力学光度法测定痕量铜的方法，方法应用于食品中痕量铜的分析。     

铜催化剂有效表面积的测定

 综述了几种测定铜催化剂有效表面积的方法．N2O前沿反应色谱法（RFC）对设备要求简单，操作简便，测定结果重现性好，是测定铜催化剂中铜的表面积的有效方法．给出了装置原理图和适当的实验条件．     

过氧化氢氧化二氯荧光素动力学荧光法测定痕量铜

研究了在氨性介质中，铜(Ⅱ)催化过氧化氢氧化二氯荧光素的褪色反应，建立了动力学荧光法测定痕量铜的新方法。方法的检出限为0．06μg/L，测定铜的线性范围为0．2～4．0μg/L。已用于人发、茶叶和自来水中痕量铜的测定。     

双波长光度法同时测定头发中微量铜和锌

研究了用双波长光度法同时测定头发中微量铜和锌。在pH9．0条件下，以锌试剂为显色剂，与铜、锌络合分别形成稳定的有色络合物．测得铜络合物的最大吸收波长为615nm．锌络合物的最大吸收波长为630nm。采用双波长光度法，选用铜的测定波长对为615／648nm，铜锌合量在波长627nm的等吸光点进行测定。铜含量和铜、锌合量的线性范围都在O～30μg／25ml范围内符合比耳定律。试验结果表明，该方法准确，简便适用，方法回收率在92％～108％之间。用于同时测定头发中微量铜和锌，结果满意。     

催化光度法测定痕量铜的新体系研究

报道了在Ｈ２ＳＯ４介质中，溴代十六烷基吡啶和活化剂乙二胺存在下，痕量铜催化抗坏血酸还原ＣａｄｉｏｎＩ（苯基重氮氨基偶氮苯）的褪色反应，测定了反应表现活化能，探讨了反应机理，建立了选择性地测定痕量铜的新方法，线性范围为０～１．４μｇ／２５ｍＬ，方法用于人发及食品中痕量铜的测定，结果满意。     

浊点萃取-火焰原子吸收光谱法测定水样中痕量铜的研究

提出了浊点萃取火焰原子吸收光谱法测定痕量铜的新方法。详细探讨了溶液pH，试剂浓度等实验条件对浊点萃取及测定灵敏度的影响，在最佳下，富集50mL样品溶液，用火焰原子吸收光谱法测定，铜的检测限为0.35μg/L，铜的富集倍率为71倍。方法用于自来水、河水及海水中痕量铜的测定。     

碘离子对铜阳极溶出的影响

本文用阳极溶出伏安法直接在玻璃电极上测定铜。在Ｈ２ＳＯ４介质中加入微量碘离子使灵敏度大大提高，可测定１ｎｇ／ｍＬ铜。该方法用于人体血清中铜的测定，结果令人满意，证明在碘离子存在下，铜溶出时生成了碘化亚铜沉淀，加速了溶出反应的进行，利用溶度积的关系来提高阳极溶出伏安法的灵敏度，是一种有效的方法。     

双席夫碱双-(2,4-二羟基苯乙酮)缩肼的合成及其与铜的荧光猝灭反应

报道了一种新的双席夫碱荧光试剂——双—(2，4—二羟基苯乙酮)缩肼的合成；试剂在492.8nm处有一强荧光峰，当有铜离子存在时，可与试剂形成稳定的配合物而使试剂的荧光猝灭；利用此反应建立了一个荧光测定痕量铜的新方法，测定铜的线性范围为0．0～180．0μg／L，检出限0．02μg／L，方法可应用于矿泉水和水中痕量铜的测定。     

铜（Ⅱ）催化DBN偶氮胂的褪色反应特性及应用

本文研究了铜（Ⅱ）催化抗坏血酸还原ＤＢＮ偶氮胂的褪色反应特性，测定了反应级数和以应的速率方程，拟定了反应的最佳条件，建立测定铜（Ⅱ）的新方法，其检出限为３．４５×１０＾１０ｇ／ｍＬ，线性范围为０～０．１２μｇ／１０ｍＬ，用于人发中痕量铜（Ⅱ）的测定，结果满意。     

病毒性肝炎、肝硬化与微量元素

（1）病毒性肝炎与微量元素锌、硒、铜有关：张冠群等测定了128例乙肝患者血清微量元素含量。结果显示，慢性乙肝患者血清锌、铜、铁含量低于常人，急性肝炎患者血清锌铜铁与常人无差异。任仲轩测定了47例老年慢性病毒性肝炎患者与45例非老年患者血清微量元素含量。结果显示，两组锌、铜、硒含量皆低于健康对照。王晋升等测定了122例急慢性肝炎患者血清微量元素含量。     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.