双波长吸光光度法同时测定多巴和酪氨酸的研究

研究了双波长吸光光度法同时测定多巴和酪氨酸。在 pH 1 2 .0 0的硼砂 氢氧化钠缓冲介质中 ,多巴和酪氨酸的含量分别在 0～ 2 0 .0 μg·ml-1和 0～ 1 9.0 μg·ml-1范围内呈良好线性关系 ,方法检出限和摩尔吸光系数 :多巴为 0 .2 3 μg·ml-1和 1 .2 0× 1 0 4L·mol-1·cm-1,酪氨酸为 0 .2 7μg·ml-1和 1 .48× 1 0 4L·mol-1·cm-1,方法的灵敏度和和选择性均较好 ,应用于尿液中多巴和酪氨酸的测定。     

焙烧富集分离-硒化氢发生原子荧光光谱法测定纯锑中微量硒

研究了一种焙烧富集分离 硒化氢发生原子荧光光谱法测定纯锑中微量硒的方法。在选定的试验条件下 ,方法检出限为 0 .0 1μg·g- 1,线性范围为 0 .0 0 1μg·ml- 1～ 0 .3μg·ml- 1,加标回收率为 94 %～ 99%。用此法测定了 5个纯锑参考样中微量硒 ,结果与参考值一致。     

次甲基蓝-溴酸钾体系动力学光度法测定甲醛

在硫酸介质中 ,基于甲醛对溴酸钾氧化次甲基蓝 (MB)显著的促进作用 ,建立了测定甲醛的动力学光度法。线性范围为 0 .4 8～ 5 .6 0 μg·ml- 1,检出限为 0 .2 2 μg·ml- 1。对浓度水平为 1.6 μg·ml- 1甲醛的 10次平行测定的RSD为 0 .4 86 %。方法用于检测酚醛树脂以及动物标本室内空气中甲醛含量 ,结果满意     

过氧化氢氧化罗丹明6G催化荧光法测定铁

基于在高氯酸溶液中痕量铁对过氧化氢氧化罗丹明 6G具有催化作用 ,建立了催化荧光法测定痕量铁的新方法。方法的检出限为 1.4× 10 - 8g·ml- 1,线性范围为 0 .0 2 0 .6 μg·ml- 1。该方法用于人发、面粉中痕量铁的测定 ,结果满意     

催化动力学交流示波极谱法测定微量钒的研究

研究了在柠檬酸-柠檬酸钠缓冲溶液中,V(Ⅴ)催化过氧化氢氧化茜素红S的褪色反应A其动力学条件,建立了一种高灵敏度、高选择性测量微量V(Ⅴ)的新方法。测定V(Ⅴ)的线性范围为1．0～6．0μg·ml-1,检出限为0．50μg·ml-1,有色溶液及沉淀不干扰测定,优于催化光度法,使得用于常量分析的交流示波极谱法可以进行微量测定。方法用于合金钢中钒的测定,结果满意。     

速差催化荧光法同时测定痕量钴和铜

基于在硼酸 硼砂介质中 ,钴和铜都能催化过氧化氢氧化还原型罗丹明 6G的反应 ,并且产生荧光强度具有加和性的特性 ,建立了速差催化荧光法同时测定痕量钴和铜的新方法。钴和铜的检出限分别为 0 .90ng·ml- 1和 0 .0 5 3μg·ml- 1;测定范围分别为 1.0 0～ 2 0 .0 0ng·ml- 1和 0 .10～1.2 0 μg·ml- 1。将方法用于生物样品中痕量钴和铜的同时测定 ,结果满意     

催化动力学光度法测定痕量碘

基于碘在高碘酸钾氧化亮绿SF增色反应中的催化活性 ,建立了高灵敏度、高选择性的催化动力学光度法测定痕量碘的方法 ,测定范围为 0 .5～ 10 μg·ml- 1,方法检出限为 0 .2 6μg·ml- 1,用于天然水的碘化物测定 ,获得满意结果     

火焰原子吸收光谱法测定重晶石中锌铜铁

提出了火焰原子吸收光谱法测定重晶石中锌、铜和铁的方法 ,相对标准偏差为 1 .7%～7.3% ,加标回收率在 95.2 %～ 1 0 3.2 %之间。特征浓度锌为 0 .0 1 0 μg·ml-1/1 % ,铜为 0 .0 35μg·ml-1/1 % ,铁为 0 .0 67μg· ml-1/1 %。方法简便、准确、可靠。     

火焰原子吸收光谱法连续测定番木瓜中铜锌铁锰

探讨了用微波消化罐消化样品、用火焰原子吸收光谱法在同一体系中测定番木瓜中微量元素铜、锌、铁、锰的方法。在微波消化罐内用硝酸和过氧化氢消化样品 ,具有试剂用量少免受污染、消化时间短等优点。考察了硝酸、过氧化氢用量以及消化时间的影响 ,以及在同一体系中铜、锌、铁、锰的干扰情况。在选定条件下 ,铜检出限为 0 .0 0 4 μg·ml- 1,锌检出限为 0 .0 0 4 8μg·ml- 1,铁检出限为 0 .0 0 3μg·ml- 1,锰检出限为 0 .0 0 6 μg·ml- 1,相对标准偏差为 1.7%～ 4 .9% ,回收率为 96 .8%～ 10 6 .6 %。方法具有简便、省时、准确、可靠的优点     

催化光度法测定痕量甲醛

基于磷酸介质中甲醛催化溴酸钾氧化溴甲酚紫的褪色反应 ,建立了测定痕量甲醛的方法。方法的检出限为 1.0× 10 - 5g·L- 1,线性范围为 0 .0 2 0～ 0 .4 8μg·ml- 1,方法简便 ,用于空气中测定痕量甲醛 ,结果满意。     

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.     

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.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.