谷胱甘肽包覆的碲化镉量子点荧光探针法快速测定多巴胺

利用多巴胺(DA)对谷胱甘肽包覆的碲化镉量子点荧光的猝灭作用,建立了快速测定多巴胺的荧光探针分析法。实验结果表明,在Tris-HCl(p H=7.0)溶液中,多巴胺浓度在0.06~2.1μmol/L范围内,碲化镉量子点荧光强度的猝灭值(ΔF)与多巴胺的浓度呈线性关系,线性方程ΔF=165.43cDA+9.57,相关系数(r)0.998 6,方法检出限0.03μmol/L。将本方法应用于样品中DA的分析,RSD为4.2%,DA的加标回收率为95.2%~104.8%。     

CdTe量子点荧光猝灭法测定四环素

以巯基乙酸为稳定剂水热法制备Cd Te量子点,考察不同条件下四环素对Cd Te量子点的荧光猝灭作用,建立一种荧光测定四环素含量的新方法。该方法的线性范围为1.0~20.0μg/m L,工作曲线为ΔF=2.308 2+9.679 3c(μg/m L),相关系数r为0.999 5,检出限(3SD/斜率)为0.025μg/m L。该方法应用于实际样品中四环素含量的测定,相对标准偏差2.3%,回收率在97.5%~103.3%。     

基于CdSe/ZnS量子点荧光猝灭法测定硫胺素

以CdSe/ZnS量子点为荧光探针,基于硫胺素(VB1)与CdSe/ZnS量子点间通过静电作用而有效猝灭CdSe/ZnS量子点荧光强度的机制,建立了一种可快速测定VB1的荧光检测方法.在最优实验条件下(pH 7.4,反应时间25 min),硫胺素(VB1)浓度在0.01 ～1 μmol/L时,CdSe/ZnS量子点荧光猝灭变化强度与硫胺素(VB1)浓度呈良好的线性关系:F0/F=0.67cCB1+1.05(R=0.999 2),方法检出限为5.1×10-3 μmol/L,相对标准偏差为1.09％.该方法可用于人体尿样中VB1的快速测定.     

荧光碳量子点测定替硝唑的应用研究

替硝唑对碳量子点的荧光具有明显的猝灭作用,在pH值=7.10的PBS缓冲溶液中,碳量子点的荧光猝灭强度与替硝唑浓度在8.0×10~(-7)～2.0×10~(-5) mol/L范围内呈线性,相关系数为0.9992,方法检出限为2.3×10~(-7) mol/L。该方法用于样品中替硝唑的测定,回收率为96.2%～101.8%。通过比对碳量子点和碳量子点-替硝唑体系的荧光寿命和吸收光谱的变化以及改变温度环境后体系猝灭常数的变化趋势,确定该碳量子点与替硝唑的猝灭机理为动态猝灭。     

基于碳量子点荧光猝灭法测定芦丁

利用微波法以柠檬酸三钠、11-氨基十一烷酸、聚乙二醇400为碳源制备碳量子点,用荧光光谱进行表征。在pH=6. 37的三酸缓冲介质中,芦丁能猝灭碳量子点在445 nm处的荧光,其猝灭程度与芦丁浓度呈良好的线性关系,探究了温度、时间、缓冲溶液及p H对荧光强度的影响,建立了碳量子点荧光猝灭法测定芦丁的新方法。方法线性范围为3～40μmol/L,相关系数为0. 9948,检出限为2. 3μmol/L。方法用于苦荞麦、藜麦中芦丁含量的检测,加标回收率为94. 0%～107. 8%。     

CdTe量子点荧光猝灭法测定四环素

以巯基乙酸为稳定剂水热法制备Cd Te量子点,考察不同条件下四环素对Cd Te量子点的荧光猝灭作用,建立一种荧光测定四环素含量的新方法。该方法的线性范围为1.0²0.0μg/m L,工作曲线为ΔF=2.308 2+9.679 3c(μg/m L),相关系数r为0.999 5,检出限(3SD/斜率)为0.025μg/m L。该方法应用于实际样品中四环素含量的测定,相对标准偏差<2.3%,回收率在97.5%20.0μg/m L,工作曲线为ΔF=2.308 2+9.679 3c(μg/m L),相关系数r为0.999 5,检出限(3SD/斜率)为0.025μg/m L。该方法应用于实际样品中四环素含量的测定,相对标准偏差<2.3%,回收率在97.5%¹03.3%。     

NAC修饰的CdS测定盐酸帕罗西汀片剂含量的研究

以N-乙酰半胱氨酸(NAC)为修饰剂,简便,无毒,快速合成了CdS量子点,并基于盐酸帕罗西汀对该量子点的荧光猝灭作用,建立了盐酸帕罗西汀片剂的含量测定方法。结果显示,在pH=7.22,Tris-HCl缓冲液浓度为0.06 mol/L,量子点浓度为0.35 mmol/L,反应25 min的最佳条件下,该系统荧光强度变化值与盐酸帕罗西汀在(0.0033~0.1810 mg/m L)范围内线性关系良好,ΔF=682.06C+19.115为线性回归方程,检测限为0.32μg/m L。结果满意。     

硫化锌掺锰量子点用于天然水中孔雀石绿磷光传感的应用研究

根据孔雀石绿对锰掺杂硫化锌量子点(Mn:Zn S QDs)的磷光猝灭作用,建立了一种快速检测天然水样中孔雀石绿的磷光传感新方法。实验结果表明,孔雀石绿浓度在0.04~0.50μmol/L和0.50~1.30μmol/L两个范围内变化时,Mn:Zn S QDs的磷光猝灭值(ΔPL)与孔雀石绿浓度变化呈线性关系,方法的检出限0.02μmol/L。本方法用于天然水加标样品中孔雀石绿的检测,RSD分别为4.98%和2.77%。     

硫化锌掺锰量子点磷光探针法快速检测牛奶中的三聚氰胺

基于三聚氰胺(MA)对谷胱甘肽(还原型)包覆的硫化锌掺锰量子点磷光的猝灭作用,建立了快速测定牛奶中MA的磷光探针法。实验结果表明,在中性溶液中,MA浓度在8.0~70.0 nmol/L范围内,磷光量子点强度的猝灭值(ΔPL)与MA的浓度呈线性关系,线性方程为ΔPL=1.59cMA+15.17,相关系数(r)为0.996 5,方法检出限4.0nmol/L。将本方法用于牛奶加标样品中MA的分析,RSD为3.26%,MA的平均回收率为90.05%~98.08%。     

CdS量子点作荧光探针检测水相中微量铜的方法研究

用巯基丙酸作为稳定剂,在水相中合成了CdS量子点。基于Cu^2＋对CdS量子点有显著的荧光猝灭作用,建立了检测水相中微量Cu^2＋的新方法。研究结果表明,在弱碱性的水溶液中,当Cu^2＋的浓度在1×10^-5-3×10^-4 mol·L^-1之间时,量子点的荧光猝灭强度△F/F与Cu^2＋的浓度之间很好地符合Stern-Volmer线性方程,线性相关系数为0.9952。方法的检出限为5.85×10^-6 mol·L^-1,相对标准偏差为3.75%,加标回收率为95.5%-118.5%。讨论了量子点的荧光猝灭机理。在研究金属离子和一些化合物的干扰作用时,发现有的物质使量子点的荧光猝灭,有的物质却使量子点的荧光强度增强,发光强度对不同的物质就具有选择性。选择合适的掩蔽剂可以消除较强的离子干扰。     

荧光薄膜的研制

通过湿法成形制得荧光薄膜,并对其进行一系列的测试,包括荧光强度、拉伸强度、伸长率,并用X-射线衍射观察其结晶度的变化,红外光谱仪分析其结构存在形式及扫描电镜观察荧光化合物的分散性。随荧光化合物的加入,荧光薄膜的强度、伸长、结晶度均有下降。     

荧光纤维的特性研究

以湿法成型制得荧光薄膜、熔融纺丝制得荧光纤维为样品,研究了荧光粉含量、凝固浴和拉伸倍数对荧光强度的影响,并对荧光牢度(耐光性)进行了研究,还从耐洗涤、耐高温、耐溶剂、耐酸碱四方面对其性能稳定性进行了研究。     

Rotations in Excited ICT States – Fluorescence and its Microenvironmental Sensitivity

Fluorescence spectroscopy as an analytical tool for various applications as well as fluorescence probes showing a sensitive behavior towards their microenvironmental properties have experienced an increasing interest in research in the last decades. Recently our group has contributed to this field of interest by introducing a novel mechanism where a planarization in the excited state occurs leading to an advantageous allowed emission. Here, we provide an overview of intramolecular charge transfer states where a rotation in the excited state causes a high sensitivity for microenvironmental changes. Furthermore, effects which influence the surroundings of the fluorophores are described in detail. Recent results where t wisted i ntramolecular c harge t ransfer (TICT) and a ggregation- i nduced e mission (AIE) effects were combined are described and a promising outlook for further research progress is provided.     

衍生于三苯基吡啶的pH探针的制备及其光谱性质

由4-氯苯甲醛、苯乙酮和氨在氢氧化钠溶液中一锅法合成了化合物4-(4-氯苯)-2,6-二苯基吡啶(Ⅰ),用1HNMR、13CNMR和FTIR对化合物Ⅰ进行了结构表征。pH滴定实验表明,化合物Ⅰ的紫外吸收和荧光发射光谱均对溶液的pH具有较强的敏感性,当溶液pH=4.70～4.22,化合物Ⅰ在256 nm的紫外吸收强度随着pH的减小而降低,在312 nm的紫外吸收强度及在403 nm的荧光强度随着pH的减小而增强。此外,热分析结果表明,化合物Ⅰ具有优良的热稳定性。     

Fluorescence Emission Properties of Polycyclic Aromatic Compounds in Review

Fluorescence emission behavior of polycyclic aromatic hydrocarbons (PAHs), polycyclic aromatic nitrogen heterocycles (PANHs), polycyclic aromatic sulfur heterocycles (PASHs) and benzofluoranthenes dissolved in organic solvents of varying polarity is reviewed. Measured fluorescence properties are used to divide aromatic solutes into two categories, probe and nonprobe molecules, depending upon whether the molecule's emission intensity ratios vary systematically with solvent polarity. Seventeen polycyclic aromatic hydrocarbon solute probes are identified and possible probe character versus molecular structure correlations are examined. Also discussed are instrumental and chemical artifacts associated with accurate determination of fluorescence emission intensities.     

Extremely efficient photoisomerization of water-soluble diphenylbutadiene dendrimers

A water-soluble diphenylbutadiene-cored poly(aryl ether) dendrimer, together with a corresponding lipophilic diphenylbutadiene dendrimer and a standard compound, (1E,3E)-1,4-bis(3,5-dimethoxyphenyl)buta-1,3-diene, were prepared and their photochemical properties were examined. The water-soluble dendrimer in aqueous solution exhibited an extremely high photoisomerization quantum yield (Φ_iso = 0.64), whereas the quantum yield of the bis(3,5-dimethoxyphenyl)butadiene reference compound in THF was much lower (Φ_iso = 0.26). The excitation spectra of the water-soluble dendrimer strongly depended on the emission wavelength and the fluorescence lifetime contained several components. These results indicate that the core unit in the water-soluble dendrimer adopts multiple conformations, one of which is distorted and can undergo photoisomerization quite easily.     

Percolation cluster on partially dissolving polymer film

Steady state fluorescence (SSF) technique was used for studying dissolution of UV-induced polymer films. These films are formed from poly(methyl methacrylate) (PMMA) chains labeled with pyrene (P) which was introduced as a fluorescence probe to monitor the dissolution processes. PMMA films in various ethylene glycol dimethacrylate (EGDM) content, cured by UV radiation, were dissolved in chlorofrom-heptane (20-80%) mixtures. Dissolution of the films were monitored in real-time by the P fluorescence intensity change in the solvent reservoir. It is observed that P intensity decreased dramatically above a critical EGDM content, which was atributed to the formation of a percolation cluster. The measured percolation threshold, (p_c=0.25) was found to be in accord with the bond percolation model. Desorption coefficients, D_d were measured for films prepared with various EGDM content and it was observed that D_d values are much lower above p_c than below p_c.     

9-Anthryl and 1-pyrenyl groups as reporters of local environments and diffusion of two N,N-dialkylanilines in polyethylene films. Excited state lifetimes determine spatial information

Changes in the static and dynamic fluorescence from two covalently attached lumophores, 1-pyrenyl and 9-anthrylmethyl, induced by the diffusion of two N,N-dialkylanilines, N,N-dimethylaniline and N,N-dioctadecylaniline, within polyethylene films of 42% crystallinity have been examined. The longer lived excited singlet state of 1-pyrenyl is found to report on events occurring within a larger surrounding volume than the much shorter lived excited singlet state of 9-anthylmethyl. In addition, diffusion of N,N-dioctadecylaniline is found to be more rapid than expected on the basis of simple molecular volume considerations and to occur through two parallel pathways. The results suggest that lumophore lifetimes can be ‘tuned’ to interrogate different volumes of host space in polymers.     

Butyl pyrene containing poly(arylene ethynylene)s for highly sensitive and selective sensing of TNT

A series of poly(arylene ethynylene)s (PAEs) containing ^tbutyl pyrene in the main chain were synthesized for nitroaromatic sensors. As control, similar polymers containing unsubstituted pyrene were also synthesized. The sensory properties of the polymers were studied towards various nitroaromatic compounds like trinitrotoluene (TNT), dinitrotoluene (DNT), nitrotoluene (NT), nitrobenzene (NB) and picric acid (PA) in solution as well as vapor state. Interestingly, all the ^tbutyl substituted pyrene containing polymers showed higher sensitivity than the corresponding unsubstituted pyrene containing polymers. Moreover, the polymers showed high sensitivity towards TNT as compared to the other nitroaromatic compounds. The sensitivity of one of the polymer PB was found several folds higher than that of the similar reported polymer containing unsubstituted pyrene ring. In addition, ^tbutyl pyrene containing polymers were found to have improved molecular weight, thermal stability, fluorescence quantum yield, film forming properties and solubility in common organic solvents as compared to the control polymers.     

Characterization and self-assembly of poly[sodium N-(11-acrylamidoundecanoyl)-l-alaninate] in water

A vesicle-forming amino acid derivatized surfactant, sodium N-(11-acrylamidoundecanoyl)-l-alaninate was polymerized to obtain a polysoap. The average molecular weight of the polysoap was determined by gel permeation chromatography. Rheological measurements suggested that the aqueous solution of the polysoap behaves as a non-Newtonian fluid. Fluorescence probe studies using pyrene as probe molecule indicated hydrophobic domain(s) (intra-chain aggregate) formation within a polymer chain. It has been found that the vesicular structure formed by surfactant monomers are retained after polymerization. The polymer forms inter-chain aggregates in concentrated solution. The dependence of fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene on temperature, pH, and urea concentration suggested strong inter-chain interactions of the polysoap. The pK_a of the surfactant units of the polymer chain and the phase transition temperature were determined. Dynamic light scattering measurements were performed to determine the mean size of the aggregates. The size of the aggregates was found to increase with the increase in polymer concentration also suggesting formation of inter-chain aggregates. The transmission electron micrographs revealed closed vesicular structures in water.