金属有机框架化合物在非均相催化反应中的应用

金属有机框架化合物(metal-organic frameworks,MOFs)是近年来出现的一种新型无机材料,不仅具有非常高的表面积和孔隙率,而且材料的框架结构丰富、可控,可用于气体吸附、生物医学以及磁性材料等,应用前景广阔。特别是MOFs在非均相催化反应中的应用更是吸引了大批学者的注意,研究发展非常迅速,已取得了许多成果。本文首先介绍了MOFs作为催化剂所具有的独特优点,实际应用中可能存在的问题,以及相应的解决方案;其次基于MOFs的三个结构要素系统总结了目前MOFs在非均相催化反应中的探索和应用;最后讨论了MOFs在非均相催化研究中需要重视的问题,以期为MOFs在非均相催化反应中的应用研究提供参考。     

金属有机框架化合物为前驱体制备MgO微粒

在溶剂热条件下,以氯化镁与3-(吡啶-3-甲氧基)邻苯二甲酸为原料,成功合成了一个镁和甲酸根构筑的三维金属有机框架化合物,X射线单晶衍射确定了其晶体结构.通过对所合成的配合物高温煅烧,得到了氧化镁微粒,应用红外光谱、粉末衍射和扫描电子显微镜等对其结构和形貌进行了表征,结果表明,合成的氧化镁纯度高,晶型完整,颗粒分布较为均匀,粒径约为50μm.     

金属有机骨架材料构建氯霉素电化学传感器的研究

本文通过水热合成法合成了镍-均苯三酸金属有机骨架材料(Ni_3(BTC)_2),并将其与聚丙烯酸钠(PAAS)混合后修饰到玻碳电极(GCE)表面,制得电化学传感器(Ni_3(BTC)_2-PAAS/GCE),用循环伏安法和差分脉冲法研究了传感器的响应性能,并用于水产品中氯霉素(CAP)检测。结果表明,Ni_(3 )(BTC)_2对CAP的还原具有较好的电催化作用。差分脉冲峰电流增加量与CAP浓度在3.1×10~(-9)～1.55×10~(-7)mol·L~(-1)范围内呈线性关系,线性方程为ΔI(μA)=139.72 C_(CAP)+9.9616(R~2=0.9988);在1.55×10~(-7)～9.3×10~(-7) mol·L~(-1)范围内呈线性关系,线性方程ΔI(μA)=33.109 C_(CAP)+26.596(R~2=0.9993),检出限为2.0×10~(-9) mol·L~(-1)。使用该传感器检测实际样品鲤鱼和虾肉中CAP的加标回收率在84.3%～96.6%之间。该传感器制作简单,稳定性、选择性和重复性好,可满足水产品中CAP的快速检测需要。     

金属有机骨架材料-核酸适配体荧光法检测沙门氏菌

基于金属有机骨架材料(Uio-66-NH2)的荧光猝灭特性以及对核酸适配体的吸附性,结合核酸适配体的高亲和力与高特异性识别能力,构建了针对沙门氏菌检测的荧光生物传感器,当有荧光素修饰的沙门氏菌、适配体被材料吸附到表面时,由于材料诱导电子转移猝灭了荧光素的荧光,若溶液中存在沙门氏菌,则沙门氏菌与其适配体特异性结合后从材料表面脱附,材料与荧光素之间的电子转移过程被切断,荧光素的荧光恢复。基于此原理构建的荧光传感器的信号与沙门氏菌浓度的对数在101~105cfu/m L范围内呈良好的线性关系,检出限(S/N=3)为7 cfu/m L,将该方法用于虾肉样品中沙门氏菌的检测,加标回收率为90.0%~108.0%,该传感器对沙门氏菌有较好的选择性与灵敏度。     

基于核酸适配体的比色生物传感器研究进展

核酸适配体因能与目标物特异性结合而被用作生物识别元件,广泛用于生物传感器的研究。基于适配体的比色生物传感器,因简便、经济且直观可视等特点,在环境保护、医疗诊断和食品安全等领域备受青睐。随着生物技术和纳米技术的迅速发展,结合不同显色途径和信号放大方法,已建立了多种操作简便、特异性强、灵敏度高的基于适配体的比色传感方法,为现场快速检测技术的发展提供了新思路和新选择。识别元件、信号探针及信号放大策略都是影响比色生物传感器准确性和灵敏度的重要因素,纳米材料和放大策略的选择及设计非常重要。本文主要基于酶催化和等离子体共振比色原理,介绍了近年来比色适配体传感器的研究进展,为高灵敏比色生物传感器的研究和应用提供参考。     

基于卵黄抗体-金属有机框架复合探针的电化学免疫传感器快速检测金黄色葡萄球菌

金黄色葡萄球菌(S.aureus)污染是影响食品质量安全的重要因素,因此迫切需要开发快速、简便的现场检测食品中S.aureus的分析方法.本研究采用灭活S.aureus免疫无特定病原体(SPF)蛋鸡,从产蛋中纯化出卵黄抗体(IgY),其可以高效、特异性地捕获S.aureus.将IgY固定在丝网印刷电极表面,可用于食品中...     

两个金属有机框架化合物对硝基芳香化合物在气/液相的荧光传感

制备了2个金属有机框架化合物[Cd_2(DDCPB)(DMF)_2(H_2O)]_n(CHD-1)和{[Zn_2(DDCPB)(DMA)_2]·DMA}_n(CHD-2)(H_4DDCPB=1,1′∶3′,1″-三联苯-3,3″,5,5″-四羧酸)。荧光测试表明:2个化合物均能在气/液两相中高效地选择性识别系列硝基芳香化合物(NACs)。溶液中NACs对2个化合物的荧光有较高的淬灭率,其淬灭常数可通过定量实验计算。CHD-1和CHD-2对溶液中的NACs显示出高选择性、优异的灵敏度和低检测限。基于2个化合物的薄膜检测对硝基苯(NB)和2-硝基甲苯(o-MNT)蒸气时也具有高灵敏度。此外,详细讨论了化合物的荧光传感机理。     

基于金属有机框架化合物纳米电催化剂的研究进展

金属有机框架化合物具有比表面积大、孔隙率高、结构有序可控等特点,近年来作为电催化材料在电化学能源储存和转化应用中备受关注。本文从金属有机框架化合物作为前驱体制备电催化剂的独特优点入手,总结了目前该类材料在电催化领域的最新研究进展,并对其今后的发展趋势以及面临的机遇和挑战进行了简单的展望。     

荧光核酸适配体功能化氧化石墨烯生物传感器用于快速检测氯霉素

开发了一种无标记和快速的检测方法基于氧化石墨烯（GO）和荧光功能性G-四聚体探针（FGP），可用于定量检测氯霉素（CAP）.FGP由氯霉素核酸适配体和富含G碱基的核酸序列组成.核酸适配体用于结合CAP，并且由富含G碱基的核酸序列在K⁺，Na⁺离子的作用下形成的G-四聚体，然后与硫磺素T（ThT）结合后用作信号分子.在没有CAP的情况下，FGP通过π-π堆积相互作用被吸附到GO的表面上，阻碍了G-四聚体的形成导致溶液中的荧光强度低.在加入CAP时，FGP的核酸适配体部分可识别并结合CAP以形成复合物，导致其从GO解吸.因此，游离的富含G的碱基序列可以形成G-四聚体结构并与ThT结合，导致溶液的荧光强度增加.我们观察到荧光强度增加与CAP浓度在2~20 nmol/L范围内呈线性关系，检测限为1.45 nmol/L.此外，该检测系统用于检测加标牛奶中的CAP，回收率在93.2%~103.3%之间.这些结果表明，开发的方法可用于有效检测实际样品中的CAP.     

Handheld Aptasensor for Sandwiched Detection of Chloramphenicol

Chloramphenicol(CAP)is an antifungal agent approved for use in aquarium.However,CAP residue imparts serious adverse effect on human health as well as the ecology.Thus,keeping track of CAP in aquatic products and its environmental metabolites are of great importance.Herein,we developed a novel and neat electrochemical aptasensor for the detection of simulated CAP residual in a sandwich fashion.The screen-printed carbon electrode was employed as the sensing platform and electrodeposited with peculiar nanogolds to enhance the electrochemical performance.For the specific recognition of such small target,a pair of chloramphenicol-binding aptamers,the primary Aptl and the secondary Apt2,were tailored as an artificial single-chained antibody couple,of which the thi-olated Aptl stood on the coated working substrate to capture the analyte,while the biotinylated Apt2 rallied the signal output.In the presence of CAP,Aptl at the lower place cooperated with the upper Apt2 pinched CAP together.After that,the reporter avidin-conjugated horseradish peroxidase associated atop the mounted biotin labels,resulting in an electrocatalytic amplification.In whole,this modular biosensing construction would set a paradigm not just for practicable checkpoint quarantine or point-of-care testing,but potentially adaptable for technological fusion with“Internet Plus”and“Internet of Things”.     

基于磁珠分离的酶联适配体检测痕量蛋白质的新型比色分析方法

以核酸适配体作为高效专一的识别/传感元件, 构建了一种新型的磁性分离和特异性捕获的检测方法. 两个适配体通过简单的生物素化修饰, 利用其与凝血酶不同位点的高亲和力形成夹心结构, 其中连接适配体的磁珠可捕获蛋白质, 加入另一个适配体及链霉亲和素标记的辣根过氧化物酶后, 通过比色法实现靶蛋白检测. 该法操作简单, 分析时间短, 对凝血酶的线性响应范围为 10~80 nmol/L, 检出限为 10 nmol/L.     

A Fluorescent Zirconium‐Based Metal‐Organic Framework for Selective Detection of Nitro Explosives and Metal Ions

In this work, a new porous Zr‐based metal‐organic framework (MOF ) with a large Brunner‐Emmet‐Teller (BET ) surface area was prepared by the solvothermal method using 4,4’‐(naphthalene‐1,4‐diyl)dibenzoic acid (NDDA ) as the organic ligand, and the luminescent detection performance was studied systematically. The experiments combing with computations indicate that the as‐synthesized material can sensitively and selectively detect nitro explosives and metal ions, especially for 2,4,6‐trinitrophenol (TNP ) and Fe³⁺, due to the possible electron transfer from inorganic moieties to organic moieties with naphthalene part. Interestingly, owing to its high porosity and large surface area, this Zr‐MOF showed quick luminescent response time (in 1 min) for TNP and Fe³⁺. The results obtained may provide useful information for the design of MOFs with the large permanent porosity in sensing applications for large molecules in the future.     

金属有机骨架材料构建环丙沙星电化学传感器的研究

本文通过水热合成法合成了钴-对苯二甲酸金属有机骨架材料Co(BDC),并将其与聚丙烯酸钠(PAAS)混合后修饰到玻碳电极(GCE)表面,制得电化学传感器Co(BDC)-PAAS/GCE,通过循环伏安法和差分脉冲法研究了传感器的响应性能,并用于水产品中环丙沙星(CIP)检测.结果 表明,在碱性条件下,Co(BDC)-PA...     

A Hairpin Electrochemical Aptasensor for Sensitive and Specific Detection of Thrombin Based on Homogenous Target Recognition

An electrochemical aptasensor was developed for sensitive and specific detection of thrombin by combining homogenous recognition strategy and gold nanoparticles (AuNPs) amplification. Streptavidin‐alkaline phosphatase was used as reporter molecule. Compared with the traditional hairpin aptasensor monitoring the distance of the redox molecule from the electrode surface, the proposed aptasensor successfully overcome the limitations of distance and improved the stability and high affinity of the aptamer hairpin through homogenous recognition, which enhanced the sensitivity and selectivity of the sensors effectively. Additionally, AuNPs were employed to increase the active area and conductivity of the electrode, thus, improving the sensitivity of the aptasensor. As a result, the designed thrombin detection sensor obtained a lower detection limit of 0.52 pM in buffer and 6.9 pM in blood serum.     

Label‐Free Electrochemical Aptasensor for Determination of Chloramphenicol Based on Gold Nanocubes‐Modified Screen‐Printed Gold Electrode

An ultrasensitive label‐free electrochemical aptasensor was developed for selective detection of chloramphenicol (CAP). The aptasensor was made using screen‐printed gold electrode modified with synthesized gold nanocube/cysteine. The interactions of CAP with aptamer were studied by cyclic voltammetry, square wave voltammetry (SWV) and electrochemical impedance spectroscopy. Under optimized conditions, two linear calibration curves were obtained for CAP determination using SWV technique, from 0.03 to 0.10 µM and 0.25–6.0 µM with a detection limit of 4.0 nM. The aptasensor has the advantages of good selectivity and stability and applied to the determination of CAP in human blood serum sample.     

Intercalation of Proflavine in ssDNA Aptamers: Effect on Binding of the Specific Target Chloramphenicol

The structural modification of ssDNA‐based aptamers upon specific binding of its target molecule leads to changes of the charge‐transfer resistance (R_ct) of a negatively‐charged free‐diffusing redox probe. The aptamer adopts a structure due to self‐hybridization which is stabilized using profalvine as intercalator. The pre‐organized aptamer structure is used to detect chloramphenicol (CAP) requiring a substantial change of the aptamer structure indicated by a CAP concentration dependent increase in the R_ct values. Pre‐incubation of the aptamer‐modified electrode with an intercalator allows for the modulation of the aptamer/target interaction and hence for a modulation of the CAP‐dependent variation of the R_ct values.     

综合化学实验：磁性金属有机骨架材料的合成及对铅的吸附

设计了一个综合实验——磁性金属有机骨架材料的合成及对铅的吸附。先合成四氧化三铁,再通过氨基修饰制备磁性金属有机骨架吸附材料。考察了此材料对铅的吸附性能,铅的浓度用火焰原子吸收光谱法测定。通过实验加深了学生对物理化学课程中吸附动力学等相关内容的理解,同时巩固了学生对仪器分析课程中的原子吸收光谱法的相关内容的掌握。     

磁敏传感器竞争免疫法检测牛奶中的氯霉素残留量

利用直接竞争免疫原理和巨磁致电阻效应,建立了磁敏生物传感器检测氯霉素的方法。制备氯霉素半抗原芯片,依次加入待测样品、生物素化抗体、链霉亲和素磁颗粒偶联物,使之发生竞争免疫反应,再利用传感器检测芯片上结合的磁颗粒数目。通过对检测条件的优化,建立了氯霉素浓度与磁颗粒数目的标准工作曲线。本方法的检测范围为0.05～100.0μg/L;检出限为50 ng/L;用于牛奶检测,回收率为95.97%～99.36%;批内相对标准偏差为0.8%～3.9%,批间相对标准偏差为1.1%～1.7%;与ELISA方法的一致相关系数达到0.98。本方法可在30 min内快速完成定量检测,为快速多靶标磁敏竞争免疫检测体系的建立提供了可行性。     

A Two-dimensional Dual-pore Covalent Organic Framework for Efficient Iodine Capture

Effectively capturing volatile radioiodine generated during the nuclear fission process is considered to be a safe way to the utilization of nuclear power. Here we report a new two-dimensional covalent organic framework(2D COF), ETTA-PyTTA-COF, as a highly efficient iodine adsorbent, which is constructed through the condensation reaction between 4,4’,4’’,4’’’-(ethene-1,1,2,2-tetrayl)-tetrabenzaldehyde(ETTA) and 1,3,6,8-tetrakis(4-aminophenyl)pyrene(PyTTA). The ETTA-PyTTA-COF possesses a permanent 1D channel porous structure with a high Brunauer-Emmet-Teller(BET) surface area of 1519 m²/g and excellent chemical and thermal stability. It shows ultrahigh iodine adsorption capability, which can reach up to 4.6 g/g in vapor owing to its high BET surface area, large π-conjugated structure and plenty of imine groups in the skeleton of the COF as effective iodine sorption sites.