基于罗丹明B/壳聚糖/SiO_(2)纳米粒子的荧光分光光度法检测苦味酸北大核心CSCD

本文基于苦味酸对罗丹明B(RhB)的荧光猝灭作用,以RhB/壳聚糖(CS)/SiO_(2)纳米粒子为探针,建立了一种检测苦味酸的荧光分析新方法。实验采用反相微乳液法,以CS为模板合成了CS/SiO_(2)纳米粒子,然后通过振荡组装制备得到RhB/CS/SiO_(2)纳米粒子,并基于苦味酸对RhB/CS/SiO_(2)纳米粒子的荧光猝灭作用实现了苦味酸的检测。在优化的实验条件下,5.0×10^(-6)~6.0×10^(-4)mol/L浓度范围内苦味酸与体系荧光猝灭值呈线性关系(r=0.9990),检出限为3.0×10^(-6)mol/L。方法用于水样中苦味酸的测定,回收率在98.0%~100.4%之间。     

荧光猝灭法测定磷酰化氨基酸

建立了通过磷酰化氨基酸水解产生无机磷酸盐猝灭铽离子-钛铁试剂络合物(Tb3 -TR)荧光探针的间接荧光法测定三种磷酰化氨基酸。在最佳实验条件下,方法测定磷酰化丝氨酸(P-Ser)、磷酰化苏氨酸(P-Thr)和磷酰化酪氨酸(P-Tyr)的线性范围分别为5.0×10-8~5.0×10-7mol/L、5.0×10-8~6.0×10-7mol/L、5.0×10-8~6.0×10-7mol/L;检出限分别为2.06×10-8mol/L、1.13×10-8mol/L和1.74×10-9mol/L。该方法最后用于卵黄高磷蛋白中含磷量的测定,取得定量结果。     

酶催化光度法测定卡托普利

基于卡托普利对牛血红蛋白模拟酶催化体系的抑制作用,建立了酶催化光度法测定卡托普利的新方法.研究了该抑制反应的最佳实验条件及动力学行为,测定的线性范围为6.23×10-8～1.25×10-5 mol/L,检出限为3.88×10 -9mol/L.对浓度为6.23×10 -6mol/L的卡托普利进行11次平行测定,其相对标准...     

基于纳米金-罗丹明B体系检测甲巯咪唑的研究

基于不同聚集态金纳米粒子(Au NPs)对罗丹明B(Rh B)的荧光猝灭作用,建立了一种简单、灵敏、快速测定药物甲巯咪唑的新方法。初步探讨了方法机理,并对p H值、反应时间、Au NPs和Rh B的浓度等实验条件进行了优化。优化实验条件下,方法的线性范围为4.38×10-8~0.876×10-5mol/L,检出限(S/N=3)为3.30×10-8mol/L。该法用于甲巯咪唑药品中甲巯咪唑的测定,获得了满意结果。     

基于Ru(bpy)_3~(2+)/AuNPs/Nafion电化学发光传感器检测己烯雌酚

利用柠檬酸钠还原氯金酸制得金纳米粒子(AuNPs),基于AuNPs/Nafion与Ru(bpy)_3~(2+)之间的静电引力,制备了Ru(bpy)_3~(2+)/AuNPs/Nafion电化学发光传感器。采用循环伏安法和电化学发光法对该传感器进行了表征,结果表明该传感器具有良好的稳定性和重现性,可实现对己烯雌酚的检测。在pH=7.0的0.1mol/L磷酸盐缓冲溶液(PBS,含0.05mol/L三正丙胺)中,当己烯雌酚与修饰电极作用15min时,电化学发光强度减少值与己烯雌酚浓度的负对数在1.0×10-10~5.0×10-7 mol/L范围内呈良好的线性关系,检出限为6.0×10-11 mol/L。对1.0×10-8 mol/L己烯雌酚平行测定11次,相对标准偏差为2.7%。测定己烯雌酚实际样品的加标回收率在98.0%~104.5%之间。     

毛细管电泳光导纤维发光二极管诱导荧光检测法同时测定肾上腺素和多巴胺

采用自行设计、组装的毛细管电泳光导纤维发光二极管诱导荧光检测装置,建立了同时测定肾上腺素(EP)和多巴胺(DA)的方法。采用胶束电动色谱分离模式,通过优化分离电压、十二烷基硫酸钠(SDS)浓度、背景电解质浓度和pH等影响因素,在最佳实验条件下,EP和DA的线性范围分别为2.2×10-9~1.1×10-7mol/L和2.6×10-8~1.2×10-6mol/L,EP和DA的检测限(S/N=3)分别为1.2×10-9mol/L和1.1×10-8mol/L。该方法可应用于人血浆中EP和DA含量的测定。     

RhB/Chitosan/SiO_2荧光纳米粒子的制备及Cu~(2+)检测应用

采用反相微乳液法合成了Chitosan/SiO_2纳米粒子,通过振荡组装将荧光染料罗丹明B(RhB)固定于该纳米粒子上,制备成RhB/Chitosan/SiO_2纳米粒子。基于Cu~(2+)对Rh B/Chitosan/SiO_2纳米粒子的荧光猝灭作用建立了定量测定Cu~(2+)的荧光分析方法,探讨了测定机理,优化了实验条件。在优化条件下,Cu~(2+)浓度与体系荧光猝灭值在2. 4×10~(-7)～2. 5×10~(-5)mol/L范围内呈线性关系,线性方程ΔF=2. 98×10~7c+612. 11(r=0. 997),检出限为0. 22μmol/L (3s/k),方法用于延河水中Cu~(2+)的测定,加标回收率为98. 7%～103. 3%。     

AgInS_2∶Mn@ZnS量子点在测定胰蛋白酶中的应用

基于胰蛋白酶能够选择性地猝灭AgInS_2∶Mn@ZnS量子点(QDs)的荧光和磷光,建立了一种检测胰蛋白酶的新方法。实验考察了AgInS_2∶Mn@ZnS QDs对常见蛋白质的选择性以及酸度的影响,优化了测定胰蛋白酶的条件。结果表明,在pH=8.0的磷酸盐缓冲溶液中,荧光猝灭法测定胰蛋白酶的线性范围为5.0×10~(-7)~4.0×10~(-6)mol/L(R=0.9975),检出限为5.0×10~(-8) mol/L;磷光猝灭法测定胰蛋白酶的线性范围为5.0×10~(-7)~3.5×10~(-6) mol/L(R=0.9940),检出限为4.7×10~(-8) mol/L。不同加标水平下的加标回收率在94.1%~107.2%之间,相对标准偏差小于3%。该方法成功地应用于尿样中胰蛋白酶的测定。     

基于两种复合纳米材料修饰的电极对多巴胺的催化氧化

本文先在Au电极表面自组装硫辛酰胺(T-NH_2),再利用电化学还原的方法将还原氧化石墨烯(ERGO)和纳米金(AuNPs)电沉积到T-NH_2表面,采用循环伏安法考察了电极的电化学性能。实验表明,该修饰电极对多巴胺(DA)具有良好的电催化作用,优化条件下,DA的氧化峰电流与其浓度在6.49×10~(-6)~7.62×10~(-3) mol/L范围内呈良好的线性关系(R=0.996),检出限为2.0×10~(-6) mol/L。     

高效液相色谱-柱后化学发光法检测人体尿液中的卡托普利

在酸性条件下,Ce?氧化Ru(bipy)32+生成Ru(bipy)33+,同时氧化卡托普利生成二硫化物中间活性态([RS-SR]*),Ru(bipy)33+和二硫化物中间活性态之间相互反应产生强烈的化学发光。基于此,根据发光试剂Ru(bipy)32+水溶性好、试剂稳定等特点,将其加入到流动相中,通过高效液相色谱分离,建立了柱后化学发光快速灵敏检测卡托普利的方法。在以甲醇-0.01mol/L KH2PO4-1g/L Ru(bipy)32+(80∶20∶2,V/V)为流动相,流速为0.9mL/min,8.0×10-4 mol/L Ce?的优化实验条件下,方法的线性范围为2.0×10-7～1.0×10-4 mol/L(R2=0.9988),检出限为6.0×10-8 mol/L(S/N=3),并对1×10-5 mol/L卡托普利平行测定11次,相对标准偏差(RSD)为1.8%。将本方法用于人体尿液中卡托普利含量的测定,结果令人满意。结合化学发光光谱,对该体系发光机理进行了探讨。     

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.