双亲聚合物分子印迹自组装胶束电化学传感器研究

结合大分子自组装和分子印迹技术制备了分子印迹聚合物胶束, 并通过电沉积将其固载到电极表面得到分子印迹电化学传感器. 首先以甲基丙烯酸二甲氨基乙酯(DMA)、丙烯酸羟乙酯(HEA)、丙烯酸二异辛酯(EHA)和苯乙烯(St)合成了共聚物poly(DMA-co-HEA-co-EHA-co-St), 在其侧链接枝上双键得到可光交联的双亲共聚物. 以水为沉淀剂诱发该双亲共聚物在含有对乙酰氨基苯酚的溶液中自组装, 得到印迹有对乙酰氨基苯酚的聚合物胶束, 利用动态激光光散射(DLS)和透射电镜(TEM)表征其尺寸和形貌. 最后通过电沉积技术诱导印迹胶束在金电极表面组装, 经紫外光辐照交联后, 洗脱模板分子形成分子印迹膜, 制备了对乙酰氨基苯酚分子印迹传感器, 通过循环伏安法、差分脉冲溶出伏安法研究此印迹传感器的性能. 实验结果表明, 该传感器对对乙酰氨基苯酚具有良好的选择性和灵敏度, 浓度响应线性范围为1×10^{-6 到4×10-3 mol/L, 检测限为3.3×10-7 mol/L.}     

高密度自由羧基氧修饰孔壁的锌基金属有机骨架靶向电化学传感对乙酰氨基酚

基于刚性苯多羧酸H₄BPTC(联苯-3,3′,5,5′-四甲酸),构筑了一例孔壁修饰高密度自由羧基氧的三维刚性锌基金属有机骨架：{[Zn₂(BPTC)(H₂O)(DMF)₂]·DMF·H₂O}_n (SXNU-5-Zn)。SXNU-5-Zn具有好的酸碱稳定性(pH=3~8)和热稳定性。以SXNU-5-Zn构建了基于纯 MOFs材料的电化学传感器(SXNU-5-Zn/GCE),其可高灵敏、选择性的检测对乙酰氨基酚(AC),检测的线性范围宽(0.02~765 μmol·L^-1),检测限低至 0.013 8 μmol·L^-1(S/N=3)。此外,所制备的 SXNU-5-Zn/GCE 传感器已成功应用于实际样品复方对乙酰氨基酚片中AC含量的检测。     

A new light emitting diode-light emitting diode portable carbon dioxide gas sensor based on an interchangeable membrane system for industrial applications

A new system for CO₂ measurement (0–100%) based on a paired emitter–detector diode arrangement as a colorimetric detection system is described. Two different configurations were tested: configuration 1 (an opposite side configuration) where a secondary inner-filter effect accounts for CO₂ sensitivity. This configuration involves the absorption of the phosphorescence emitted from a CO₂-insensitive luminophore by an acid–base indicator and configuration 2 wherein the membrane containing the luminophore is removed, simplifying the sensing membrane that now only contains the acid–base indicator. In addition, two different instrumental configurations have been studied, using a paired emitter–detector diode system, consisting of two LEDs wherein one is used as the light source (emitter) and the other is used in reverse bias mode as the light detector. The first configuration uses a green LED as emitter and a red LED as detector, whereas in the second case two identical red LEDs are used as emitter and detector. The system was characterised in terms of sensitivity, dynamic response, reproducibility, stability and temperature influence. We found that configuration 2 presented a better CO₂ response in terms of sensitivity.     

A sensitive amperometric sensor for hydrazine based on Pt nanoparticles-reduced graphene oxide–multi-walled carbon nanotubes composite

The platinum nanoparticles-reduced graphene oxide-multi-walled carbon nanotubes composite (PtNPs-rGO-MWCNTs) has been synthesised by one-step chemical co-reduction strategy in ethylene glycol (EG) system using sodium citrate as reducing agent. The X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), as well as the electrochemical methods have been used for the characterisation of this composite. Benefiting from the large effective surface and good carrier function of rGO-MWCNTs, PtNPs in this nanocomposite have some excellent characteristics such as small particle size, good dispersion, as well as high electrocatalytic activity. Based on this, a new electrochemical sensor for hydrazine has been fabricated using dropping method. Under the optimum conditions, the linear range for the determination of hydrazine by amperometry at 0.20 V (vs. SCE) in phosphate buffer (pH 7.0) is from 2.0 × 10^?7 mol L^?1 to 2.3 × 10^?3 mol L^?1. The detection limit and sensitivity is 4.5 × 10^?8 mol L^?1 (S/N = 3) and 219.7 μA mM^?1, respectively. This sensor has some attractive analytical features such as low detection limit, wide linear range, high sensitivity, as well as good stability.     

Novel coumarin-based containing denrons selective fluorescent chemosesor for sequential recognition of Cu2+ and PPi

In this study, we have successfully synthesized a novel coumarin-based dendrons derivative CD and its chemical structure was characterized by ¹H NMR, ¹³C NMR and ESI-HR-MS. The sensor CD showed an obvious “on-off” fluorescence quenching response toward Cu²⁺ with a maximum quenching efficiency of 99.8%. The CD-Cu²⁺ complex showed an “off-on” fluorescence enhancement response toward PPi over many competitive anions. The detection limit of the sensor CD was 0.29?×?10^?6?M to Cu²⁺ and 2.39?×?10^?9?M to PPi. In addition, the sensor CD showed a 1:1 binding stoichiometry to Cu²⁺ and the sensor CD-Cu²⁺ showed a 2:1 binding stoichiometry to PPi in CH₃CN/HEPES buffer medium (9:1 v/v, pH?=?7.2). The stable pH range of sensor CD to Cu²⁺ and CD-Cu²⁺ to PPi was from 3 to 8.     

基于水分散纳米无定形水杨酸甲酯铽配合物的三价铬离子高灵敏荧光传感器

为扩大稀土荧光配合物的应用范围,满足水溶液中微量铬的高灵敏高选择性探测要求,制备了一种基于水分散纳米无定形水杨酸甲酯铽配合物(A-MS-Tb)的高灵敏三价铬离子荧光传感器。结果表明:在水溶液中直接反应合成的配合物A-MS-Tb为无定形的纳米沉淀,其粒子尺度在50～100 nm之间,具有与报道的配合物晶体类似的组成。该配合物在494、549、591和625 nm处呈现出强的荧光发射,归属于铽离子的5D4→7FJ(J=6,5,4,3)能级跃迁。A-MS-Tb与晶体配合物的显著差别在于其在水中的悬浮稳定性和荧光稳定性更好,这对于其作为荧光材料和离子传感器非常重要。尤其突出的是,当将三价铬离子加入到它的水悬浮溶液中后,会减弱配体与铽离子之间的配位作用,导致其绿色荧光被淬灭。据此,构建了一种高灵敏测定溶液中铬离子浓度的荧光探针,并对其分析的选择性、灵敏度和抗干扰能力进行了评价。     

纳米光学传感器用于检测汞离子

汞离子是毒性最大的重金属之一,对环境和人体都会造成严重的不良影响,开发能够快速检测环境中汞离子的分析方法引起了越来越多的关注。纳米材料由于其优良的光学性能和良好的稳定性,被广泛用于环境中汞离子的检测。本文主要综述了近年来一些代表性的基于纳米材料的汞离子荧光、比色传感器。根据纳米材料的不同,将这些传感器分为基于金、银、碳和硅基材料,以及量子点、有机纳米颗粒和其他纳米基材料的荧光、比色传感器,并分别从设计原理、识别性能和实际应用等方面对这些传感器进行了描述和讨论。最后对该领域的研究和发展提出了展望。     

Fluorene‐based Lanthanide Coordination Polymer: Structure,Luminescence and Sensing of Picric Acid

Luminescent coordination polymers can be potential chemosensors and extensive efforts are being devoted to improve their selectivity and sensitivity. In this work, we report a new kind of fluorene‐based Tb‐CP, Tb₄L₆·7DMF·5H₂O ( Tb ₄ L ₆ , H₂L = 4,4′‐(9,9‐dimethyl‐9H‐fluorene‐2,7‐diyl)dibenzoic acid), showing 2D network and strong blue emission. Meanwhile, Tb ₄ L ₆ exhibits excellent selectivity and sensitivity for picric acid (PA). The quenching constant (K_sv) of Tb ₄ L ₆ is equal to 4.5 × 10⁴ L/mol during the concentration range of 0–30 μmol/L, which approaches the best reported CPs‐based on PA sensor up to now. Moreover, we went into depth on the possible mechanisms of luminescence quenching.     

A stable pillared metal–organic framework constructed by H4TCPP ligand as luminescent sensor for selective detection of TNP and Fe3+ ions

A novel luminescent metal–organic framework ( Zn‐TCPP/BPY ) with pillared structure based on 2,3,5,6‐tetrakis(4‐carboxyphenyl)pyrazine (H₄TCPP) and 4,4′‐bipyridine (BPY) has been designed and synthesized through a solvothermal reaction. The [Zn₂(COO)₄] paddlewheel units are linked by TCPP^4? ligands to form two‐dimensional layers and further connected by BPY ligands as pillars to construct the twofold interpenetrating three‐dimensional framework. Interestingly, Zn‐TCPP/BPY possesses outstanding stability in organic solvents and water as well as maintains its structural rigidity in aqueous solutions of different pH values (3–12). After activation, Zn‐TCPP/BPY possesses permanent porosity with Brunauer–Emmett–Teller surface area of 630 m² g^–1. Remarkably, Zn‐TCPP/BPY displays excellent fluorescent property in virtue of the aggregation‐induced emission effect of the H₄TCPP ligand, which can be highly active and quenched by small amounts of 2,4,6‐trinitrophenol (TNP) and Fe³⁺ ions. Furthermore, the detection effect of Zn‐TCPP/BPY remains basically the same even after five cycles. The excellent stability, high sensitivity, and recyclability of Zn‐TCPP/BPY make it an outstanding chemical sensor for detecting TNP and Fe³⁺ ions.