新型Cd(Ⅱ)-MOF的合成及对4-硝基苯胺的高效识别

采用新型1,3,5-三(1H-苯并[d]咪唑-2-基)苯(TBB)配体及2,5-二羟基对苯二甲酸(H₂dhtp)线性配体, 以Cd(Ⅱ)离子为中心节点, 构筑了具有新型拓扑结构(unj)的手性金属-有机框架材料[Cd(TBB)(dhtp) ](配合物1). 该配合物具有较强的光致发光性能, 可分散在溶液中荧光检测硝基配合物等污染物. 其中, 4-硝基苯胺对配合物1具有高效的荧光猝灭能力, 检测限可低至0.145 mg/L, 并具有较好的选择性.     

Biochemical and computational insights of adenosine deaminase inhibition by Epigallocatechin gallate

Epigallocatechin gallate, a flavonoid from Camellia sinensis possess various pharmacological activities such as anticancer, antimicrobial and antioxidant etc. Adenosine deaminase, (ADA), is a key enzyme involved in the purine metabolism, the inhibitors of which is being considered as highly promising candidate for the development of anti-proliferative and anti-inflammatory drugs. In this work we studied adenosine deaminase inhibitory activity of epigallocatechin gallate by using biophysical and computational methods. The enzyme inhibition study result indicated that epigallocatechin gallate possess strong inhibitory activity on ADA. ITC study revealed the energetics of binding. Also the binding is confirmed by using fluorescence spectroscopy. The structural details of binding are obtained from molecular docking and MD simulation studies.     

Fluorescent macrocyclic chemosensor for Zn(II) detection at alkaline pH values

ABSTRACT

The new macrocyclic ligand L (28,29-dimethoxy-27-oxa-8,11,14,17,25,26-hexaazatetracyclo[22.2.1.1(2,6).1(19,23)]nonacosa-2,4,6(28),19,21,23(29),24,26(1)-octaene) has been synthesised. It contains a tetramine chain and the 2,5-bis(2-methoxy-3-metyl-phenyl)-1,3,4-oxadiazole (PPD-OMe) chromophore, acting as coordinating and sensing units, respectively.

The fluorescent emission of L depends on the pH being highly fluorescent at pH = 2 and not emitting from pH >10. The studies highlighted that L is a PET mediated emitting chemosensor, being the PET effect regulated by the degree of the tetraamine protonation.

L coordinates metal ions (Cu(II), Zn(II) and Cd(II)) in water giving rise to an OFF-ON fluorescent response for the presence of Zn(II) ion thus signalling its presence in the medium. This response is particularly notable at pH = 9 allowing to extend the Zn(II) sensing also in the alkaline pH field.     

Bioinspired fluorescent dihydroxyindoles oligomers

In this paper we report the desgin and synthesis of dihydroxyindoles oligomers based reversible fluorescence sensor.We find dihydroxyindoles-2-carboxylic acid derived oligmer(P-DHICA)has the highest selectivity and sensitivity for Cu^2+detection.This work provide a highly efficient,environmentally friendly biosensor for potential use in medical testing.     

高光学质量氮化碳薄膜的制备和表征

氮化碳(graphitic carbon nitride,g-CN)作为一种非金属半导体材料已被广泛应用于多种能源相关领域研究中。目前由于制备高质量g-CN薄膜的困难,大大限制了其在实际器件上的应用。本文中,我们报道了一种可制备高光学质量gCN薄膜的方法:即由三聚氰胺先通过热聚合制备本体g-CN粉末,再由本体g-CN粉末经过气相沉积在ITO导电玻璃或钠钙玻璃基底上制备g-CN薄膜。扫描电子显微镜和原子力显微镜的测量结果表明在ITO玻璃基底上形成的g-CN薄膜形貌结构均一且致密,厚度约为300nm。扫描电镜能量色散能谱和X射线光电子能谱测量结果表明在ITO玻璃基底上制备的g-CN薄膜的化学组成与本体g-CN粉末的化学组成基本一致。同时,我们发现制备的g-CN薄膜和本体g-CN粉末一样在光照射下可以有效降解亚甲基蓝染料。此外,我们还测量了制备的g-CN薄膜的稳态吸收光谱、稳态荧光光谱、荧光寿命和价带谱,并运用吸收光谱和价带谱数据确定了其能带结构。     

A fluorescence toolbox: A review of investigation of electrophoretic separations,process, and interfaces

This review focuses on fluorescence spectroscopy techniques for the investigation of electrophoretic separations. Fluorescence has been used as a sensitive detector for capillary, gel, and microchip electrophoresis for decades. However, advanced fluorescence methods can be used to study transport, interfacial phenomena, intermolecular and affinity interactions, and other processes that occur during separation. This so‐called spectroscopic toolkit can be implemented to understand fundamental behavior in electrophoresis and electrokinetic chromatography. Techniques such as fluorescence recovery after photobleaching, fluorescence correlation spectroscopy, and fluorescence anisotropy are discussed in relation to electrophoretic separations. Newer methods such as super‐resolution microscope are also introduced.     

Analysis of catecholamines and related compounds in one whole metabolic pathway with high performance liquid chromatography based on derivatization

The simultaneous determination of Tyr, catecholamines and their metabolites in one whole metabolic pathway using high performance liquid chromatography coupled with fluorescence detection (HPLC–FLD) based on pre-column derivatization has been achieved successfully. 1,3,5,7-Tetramethyl-8-(N-hydroxysuccinimidyl butyric ester)-difluoroboradiaza-s-indacene (TMBB-Su), a highly reactive fluorescent reagent synthesized in our previous work, was used for the labeling of tyrosine (Tyr), l-3,4-dihydroxyphenylalanine (l-DOPA), dopamine (DA), norepinephrine (NE), epinephrine (E) and metanephrine (MN). Derivatization conditions including reagent concentration, buffer, reaction temperature and reaction time were also investigated to improve the derivatization efficiency and thus the sensitivity of the detection. The separation of the derivatives was obtained on C₁₈ column with the mobile phase of 20 mM pH 3.5 citric acid (H₃Cit)–sodium hydrogen phosphate (Na₂HPO₄) buffer and methanol. Good linearities with correlation coefficients square (R²) greater than 0.998 in the corresponding concentration ranges were observed and the detection limits (S/N = 3) were found in the range from 0.10 to 0.40 nM (l-DOPA: 1.45 nM). The proposed method has been applied to the detection of catecholamines and related compounds in mice liver and brain samples without tedious extraction or purification procedure, which exhibits excellent selectivity and sensitivity in the analysis of complex samples. This work provides an alternative approach in the metabolic research of catecholamines and is helpful for the study of catecholamine metabolism.     

基于P2 Mo18O6-62@Tb3+溶液可逆变色-荧光开关性质对维生素C和H2O2的光谱检测

基于变色多酸P₂Mo₁₈{\mathrm{O}}_{62}^{6-}与绿光Tb³⁺之间的功能互补及分子间能量转移的原理, 在维生素C(VC)的还原下, P₂Mo₁₈{\mathrm{O}}_{62}^{6-}@Tb³⁺溶液由浅黄色变为蓝色, 发生荧光猝灭; 相反, 在H₂O₂氧化下, 溶液的蓝色褪去, 荧光得以恢复, P₂Mo₁₈{\mathrm{O}}_{62}^{6-}@Tb³⁺溶液呈现出可逆的化学响应变色及荧光开关性质. 利用紫外-可见(UV-Vis)及荧光(PL)光谱法对VC浓度进行定量检测, 分别以800 nm处的吸光度和 547 nm处荧光强度的对数值对VC浓度作图, 获得光谱法对VC检测的线性方程, 检出限分别为3.40×10^-3和0.21 μmol/L; 利用UV-Vis及PL动力学方法对VC和H₂O₂检测的响应速度进行了考察, 响应时间分别为52和320 s; 通过UV-Vis光谱及动力学方法考察了VC检测的选择性及可重复使用性.     

单分散键合型含铕聚苯乙烯微球的制备与荧光传感性能

制备了一种可定性定量检测水溶液中三价铁离子的含铕聚苯乙烯微球, 分别用固体核磁碳谱(¹³C CP/MAS NMR)、 傅里叶变换红外光谱(FTIR)、 X射线光电子能谱(XPS)、 扫描电子显微镜(SEM)、 透射电子显微镜(TEM)、 元素分析、 粒度分析和ζ电位分析等对其化学组成和结构形貌进行表征. 当铕配合物单体用量低于2.5%时, 可以得到稳定的单分散键合型含铕聚苯乙烯微球. 用紫外光激发时, 该含铕聚苯乙烯微球发射铕离子的特征红光. Fe³⁺能猝灭该微球的荧光, 酸根离子和其它金属离子对其干扰较少; 猝灭效率与Fe³⁺浓度在0~300 μmol/L浓度范围内均呈线性关系; 随着铕配合物单体用量的增加, 微球的荧光增强, 其在检测Fe³⁺的荧光时, 猝灭常数(K_SV)增加, 检测限(LOD)下降. 调节铕配合物单体的用量, 可获得热性能优异、 红光发射强度高且稳定性好的单分散聚苯乙烯荧光微球, 对Fe³⁺荧光检测显示出较高的选择性, 在生物检测和环境保护等领域具有较高的应用价值.     

一种非接触式稀土荧光自参比温度传感器

发展了一种非接触式稀土荧光自参比温度传感器，即将有机稀土配合物K[Yb(Az)₄]包埋在苯乙烯-甲基丙烯酸甲酯共聚物中，并附着在洁净的石英片上制备得到了温度传感薄膜Yb@PSMM。通过研究不同温度下Yb3+的荧光发射光谱，利用其在近红外波段荧光性质随温度变化的规律，开发了一种比率型稀土荧光温度传感方法，其原理是通过不同温度下Yb3+的荧光发射光谱的形状随温度的变化，结合在不同温度下Yb3+的核外电子在外层Stark劈裂亚能级上的分布符合Boltzmann分布律的特点，利用其近红外荧光发射光谱中900 nm~990 nm波长范围内与990~1 150 nm波长范围内的积分峰面积比的自然对数与温度的倒数呈现的线性关系作为温度测量的标准曲线，实现了-195~105 ℃范围内的温度精确测量。经考察，该发光温度传感器在0 ℃附近的温度测量分辨率达到了0.1 ℃。与已报道的发光温度传感器相比，提出的新型温度传感器具有如下几个优势：其一，所选用的发光材料的Stokes位移大于500 nm，有效地避免了环境背景干扰；其二，由于采用荧光积分峰面积而非荧光强度作为考察对象，大大减小了测量中由于仪器或测量次数较少引入的随机误差；其三，采用同一发光材料的荧光发射光谱中两个荧光峰面积的比值，相当于在体系中引入了自参比，有效避免了由于荧光材料的浓度、几何构型以及光源强度等外界因素变化对测量结果产生的影响；其四，利用稀土发光材料作为温度传感材料，可以利用其荧光寿命长、单色性好、强度高的特点；其五，温度传感膜本身不溶于水，也不在水中扩散，便于直接测量原位温度变化；其六，Yb3+的发光位于900~1 150 nm的近红外波长范围，而这个波段的荧光具有较好的穿透性使得该温度传感器有望在复杂体系的温度传感、成像等领域发挥重要作用。在实际测量的装置中，通过调整光路使得辐照在样品上的入射光斑大小仅约为1 mm2，并将Yb@PSMM固体膜样品的放置方向与入射激发光的夹角设置为225°，从而规避了入射光源的反射光对检测器的影响，而具有较好穿透能力的近红外荧光几乎不受影响，从而进一步确保了该温度传感器的测量结果。