重要传感材料荧光共轭聚合物PPESO3的一种新的简便合成路线

本文提出了一种新的简便得多的合成路线, 既避免了BBr3的使用, 又简化了反应步骤, 使PPESO3的合成简单易行, 为更广泛地对其进行研究与应用提供了便利条件. 此外, 本文还研究了PPESO3与非离子表面活性剂(聚乙烯吡咯烷酮, PVP)之间的相互作用, 结果表明, PVP与PPESO3形成了稳定的络合体, 可以有效地打破聚合物在水溶液中的聚集, 提高荧光量子产率.     

A Review of Surface Functionalized Amine Terminated Dendrimers for Application in Biological and Molecular Sensing

Dendrimers are three dimensional nanosized synthetic molecules that have internal cavities and numerous surface groups. In recent times they have received increased attention in sensing applications. For dendrimers to be used as sensors, they most commonly require functionalization at their surface. This is because the surface is generally the first point of contact between the dendrimer and the outside world, hence surface functionalization serves to selectively home in on the target analyte. Further, sensor signals may be transmitted through surface functionalities e.g. fluorochromic molecules. It is therefore important to document surface functionalization approaches. Dendrimers with amine surface groups have the advantage of being able to be conjugated to other molecules via an amide linkage, which is one of the most fundamental and widespread chemical bonds in nature. In this paper we demonstrate the properties of dendrimers that make them so applicable to sensing. We review several methods for functionalizing dendrimers via an amide linkage, as well as present a review of surface functionalized polyamidoamine, polyamine, and polypeptide dendrimers that have been employed for biological, chemical and molecular sensing.     

Spectroelectrochemical Investigation of TPPMn(III/II)‐Driven Liquid | Liquid | Electrode Triple Phase Boundary Anion Transfer into 4‐(3‐Phenylpropyl)‐Pyridine: ClO4−, CO3H−, Cl−, and F−

The triple phase boundary transfer of anions from the aqueous into an organic phase can be driven electrochemically here with the tetraphenylporphyrinato‐Mn(III/II) (or TPPMn) redox system in 4‐(3‐phenylpropyl)‐pyridine) (or PPP). Anions investigated are perchlorate, chloride, fluoride, and bicarbonate. The bicarbonate and fluoride transfer processes are shown to be chemically more complex compared to the perchlorate and chloride cases with UV‐vis‐spectroelectrochemical measurements indicating a combination of HCO₃^?/CO₃^2? transfer processes and association of fluoride with TPPMn(III)⁺, respectively. In situ spectroelectrochemistry is developed for ion‐transfer voltammetry into sub‐microliter organic phase regions on mesoporous ITO conducting film electrodes.     

Parallel Detection of Different DNA Sequences on One Gold Electrode

Motivated by the potential of electrochemical techniques to analyze hybridization events fast and in a simple and cost‐effective way we present here a detection system allowing a parallel electrochemical DNA analysis. For this purpose different probe DNA strands have been immobilized on one electrode. By the use of two different target DNA sequences, both marked with the redox active methylene blue, we can show that hybridization with the complementary probe sh“NA strands can occur without steric hindrance. Each target has been recognized down to 3nM with a very high specificity of the sensor. In addition, we can detect two different ssDNA targets labeled with different redox active molecules, methylene blue and ferrocene, on one sensor surface simultaneously.     

Ultrathin Carbon Film Electrodes from Vacuum‐Carbonised Cellulose Nanofibril Composite

A novel way to produce ultrathin transparent carbon layers on tin‐doped indium oxide (ITO) substrates is developed. The ITO surface is coated with cellulose nanofibrils (from sisal) via layer‐by‐layer electrostatic binding with poly(diallyldimethylammonium chloride) or PDDAC acting as the binder. The cellulose nanofibril‐PDDAC composite film is then vacuum‐carbonised at 500 °C. The resulting carbon films are characterised by atomic force microscopy (AFM), small angle X‐ray scattering (SAXS), wide‐angle X‐ray scattering (WAXS), and Raman methods. Smooth carbon films with good adhesion to the ITO substrate are formed. The electrochemical characterisation of the carbon films is based on the oxidation of hydroquinone and the reduction of benzoquinone in aqueous phosphate buffer media. A modest effect of the cellulose nanofibril‐PDDAC film on the rate of electron transfer is observed. The effect of the film on the rate of electron transfer after carbonisation is more dramatic. For a 40‐layer cellulose nanofibril‐PDDAC film after carbonisation a two‐order of magnitude change in the rate of electron transfer occurs presumably due to a better interaction of the hydroquinone/benzoquinone system with the electrode surface.     

Electrochemical Characterization of Gold 6‐Amino‐2‐mercaptobenzothiazole Self‐Assembled Monolayer for Dopamine Detection in Pharmaceutical Samples

A new sensor, gold‐6‐amino‐2‐mercaptobenzothiazole (6A2MBT), was fabricated via a self‐assembly procedure. Electrochemical properties of the monolayer were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The modified electrode showed excellent antifouling property against the oxidation products of DA, allowed us to construct a dynamic calibration curve with two linear parts, 1.00×10^?6 to 3.72×10^?4 and 3.72×10^?4 to 6.42×10^?4 M DA, with correlation coefficients of 0.997 and 0.992 and a detection limit of 1.57×10^?7 M DA by using differential pulse voltammetry (DPV), respectively. Finally, the performance of the Au‐6A2MBT modified electrode was successfully tested for electrochemical detection of DA in a pharmaceutical sample.     

Stability Improvement of Prussian Blue by a Protective Cellulose Acetate Membrane for Hydrogen Peroxide Sensing in Neutral Media

The cellulose acetate covered Prussian blue modified glassy carbon electrode (GCE/PB/CA) was fabricated as a novel hydrogen peroxide sensor. It was shown by scanning electron microscope (SEM) and atomic force microscope (AFM) that Prussian blue was covered and protected by cellulose acetate perfectly. The modified electrode showed a good electrocatalytic activity for H₂O₂ reduction in neutral aqueous solution. H₂O₂ was detected amperometrically in 0.05 mol/L phosphate buffer solutions (pH 7.0, containing 0.1 mol/L KCl as supporting electrolyte) at an applied potential of ?0.2 V (vs. SCE). The response current was proportional to the concentration of H₂O₂ in the range of 1.0×10^?5 mol/L to 2.5×10^?4 mol/L with the detection limit of 2.2×10^?6 mol/L at a signal to noise ratio 3.     

Nonenzymatic Electrochemical Glucose Sensor Based on Pt Nanoparticles/Mesoporous Carbon Matrix

A nonenzymatic amperometric sensor for sensitive and selective detection of glucose has been constructed by using highly dispersed Pt nanoparticles supported onto mesoporous carbons (MCs). The Pt nanoparticles/mesoporous carbons (Pt/MCs) composites modified electrode displayed high electrocatalytic activity towards the oxidation of glucose. At an applied potential of 0.1 V, the Pt/MCs electrode has a linear dependence (R=0.996) in the glucose concentration up to 7.5 mM with a sensitivity of 8.52 mA M^?1 cm^?2. The Pt/MCs electrode has also shown highly resistant toward poisoning by chloride ions and without interference from the oxidation of common interfering species.     

Rigid ferrocenophane and its metal complexes with transition and alkaline-earth metal ions

The rigid [6]ferrocenophane, L¹, was synthesised by condensation of 1,1′-ferrocene dicarbaldehyde with trans-1,2-diaminocyclohexane in high dilution at r.t. followed by reduction. When other experimental conditions were employed, the [6,6,6]ferrocenephane (L²) was also obtained. Both compounds were characterised by single crystal X-ray crystallography. The protonation of L¹ and its metal complexation were evaluated by the effect on the electron-transfer process of the ferrocene (fc) unit of L¹ using cyclic voltammetry (CV) and square wave voltammetry (SWV) in anhydrous CH₃CN solution and in 0.1 M ⁿBu₄NPF₆ as the supporting electrolyte. The electrochemical process of L¹ between −300 and 900 mV is complicated by amine oxidation. On the other hand, an anodic shift from the fc/fc⁺ wave of L¹ of 249, 225, 81 and 61 mV was observed by formation of Zn²⁺, Ni²⁺, Pd²⁺ and Cu²⁺ complexes, respectively. Whereas Mg²⁺ and Ca²⁺ only have with L¹ weak interactions and they promote the acid-base equilibrium of L¹. This reveals that L¹ is an interesting molecular redox sensor for detection of Zn²⁺ and Ni²⁺, although the kinetics of the Zn²⁺ complex formation is much faster than that of the Ni²⁺ one. The X-ray crystal structure of [PdL¹Cl₂] was determined and showed a square–planar environment with Pd(II) and Fe(II) centres separated by 3.781(1) Å. The experimental anodic shifts were elucidated by DFT calculations on the [ML¹Cl₂] series and they are related to the nature of the HOMO of these complexes and a four-electron, two-orbital interaction.