A Novel Holmium(III) Membrane Sensor Based on N‐(1‐Thien‐2‐Ylmethylene)‐1,3‐Benzothiazol‐2‐Amine

Abstract

A novel plasticized membrane sensor for Ho(III) ions based on N‐(1‐thien‐2‐ylmethylene)‐1,3‐benzothiazol‐2‐amine (TBA) as a neutral carrier was prepared. The best performance was obtained with a membrane composition of 31% PVC, 61% benzyle acetate, 2% sodium tetra phenyl borate and 6% carrier. The electrode exhibits a Nernstian response for Ho(III) ions over a particular concentration range (1.0×10^?5?1.0×10^?2 M) with a slope of 19.7±0.2 mV decade^?1. The limit of the detection is 7.0×10^?6 M. The sensor has a response time of <15 s and a useful working pH range of 4.0–9.5. The proposed sensor discriminates relatively well towards Ho(III) ions with regard to common alkali, alkaline earth, and specially lanthanide ions. It was successfully applied as an indicator electrode in a potentiometric titration of Ho(III) ions with EDTA. It was also applied in determination of fluoride ions in a mouth wash preparation. The proposed sensor was applied for the determination of Ho(III) ion concentration in binary mixtures.     

A Novel Proton Sensor with Luminescence and Color Signaling Based on Platinum(II) Terpyridyl Acetylide Complex

Molecular switches that are controllable, reversible and readable at molecular level are an essential compo-nent of molecular electronics1 and chemical sensors.2-6 Of particular interest are the molecules which show dramatic and reversible changes in color and/or lumi-nescence in visible spectral region upon exposure to specific substrates. A number of chromophore- spacer-receptor systems that can selectively recognize specific guest molecules at their receptor site and pro-duce measurable col…     

Barium(II)-PVC Membrane Sensor Based on 4-4′-Methylenediantipyrine as a Neutral Carrier

Abstract

A highly selective and sensitive poly(vinyl chloride) membrane electrode, using 4-4′-Methylenediantipyrine as an ionophore, has been prepared and examined as a Ba²⁺-selective electrode. The influence of the anion excluder (sodium tetraphenyl borate, NaTPB) and the effect of the plasticizers dibutyl phthalate (DBP), nitrobenzene (NB), and benzyl acetate (BA) were studied. The best performance was obtained with the sensor having a membrane composition (w/w) of (MAP, 2.0%), (PVC, 30%), (NB, 66%), (NaTPB, 2.0%) with a wide working concentration range of 1.0 × 10^?6 to 1.0 × 10^?2 M between the pH values of 3.4 and 10.6. Furthermore, a Nernstian slope of 29.7±0.3 mV/decade of activity was demonstrated with a response time of 15 s. The sensor could be used over a period of 2 months with no potential divergence, revealing a good selectivity for a broad variety of cations including alkali, alkaline earth, heavy and transition metals. Regarding the practical applicability of this sensing device, it was successfully applied for the Ba²⁺ ions detection in a lithophone pigment and as an indicator electrode in the potentiometric titration of the under study cations.     

Bis Crown Ethers( Ⅸ)——Caesium Selective PVC Membrane Electrodes Based on Schif f Base Type of Bis Crown Ethers

Recently, much attention has been focused on the use of neutral carrier species as membrane components to extract ions from aqueous solution into a hydrophobic membrane phase. Some potassium-or caesium-selective electrodes based on bis-benzo-15-crown-5 or bis-benzo-18-crown-6 containing ester or other linkage were prepared by K. Kimura and K. W. Fung. The selective coefficients K_(K,Na)~(pot), K_(Cs,Na)~(pot),or K_(Cs,K)~(pot), K were 2.6×10~(-4), 1.9×10~(-2) and 1.7×10~(-1), respectively.     

A Novel DNA‐Enrichment Technology Based on Amino‐Modified Functionalized Silica Nanoparticles

Abstract

In this paper we report a novel DNA‐enrichment technology based on amino‐modified functionalized silica nanoparticles. The approach takes advantage of the amino‐modified silica nanoparticles that have been prepared in one step by the controlled synchronous hydrolysis of tetraethoxysilane and N‐(β‐amimoethyl)‐γ‐aminopropyltriethoxysilane in water nanodroplets of water‐in‐oil microemulsions. The functionalized silica nanoparticles display a positive surface charge at neutral pH due to the presence of amino groups on the surface of these nanoparticles. DNA‐enrichment has been realized in the form of nanoparticle–DNA complexes that is accomplished through electrostatic binding between the positive charge of the amino group and the negative charge of the phosphate groups of the nucleic acid. These nanoparticles have high affinity to bind DNA. The results show that 1 mg of nanoparticles can bind 97.2 µg of plasmid DNA with 4.3 kb. This novel DNA‐enrichment technology has been used successfully in gene delivery.     

Highly Selective Thiocyanate Electrode Based on Bis‐bebzion Schiff Base Binuclear Copper(II) Complex as Neutral Carrier

Abstract

A highly selective polyvinyl chloride (PVC) membrane electrode, based on N,N′‐(aminoethyl)ethylenediamide bis(2‐benzoideneimine) binuclear copper(II) complex [Cu(II)‐AEBB] as neutral carrier, was prepared for thiocyanate (SCN^?) determination, which displays an anti‐Hofmeister selectivity sequence for a series of anions in the following order: SCN^?>ClO₄ ^?>Sal^? > I^?>NO₃ ^?>Br^?> Cl^?>NO₂ ^?>SO₃ ^2?>F^?>H₂PO₄ ^?>SO₄ ^2?. The electrode exhibited near‐Nernst response for SCN^? with a slope of –59.0 mV/decade over a wide concentration range (8.5×10^?7～6.8×10^?1 mol/L) with a detection limit of –5.0×10^?7 mol/L in pH 5.0 phosphate buffer solution at 25°C. Alternating current (AC) impedance and equivalent circuits were used to investigate the thiocyanate response mechanism of the membrane doped with [Cu(II)‐AEBB].     

A Novel Amperometric Nitric Oxide Sensor Based on Polythionine / Nation Modified Glassy Carbon Electrode

A novel amperometric sensor for the determination of nitric oxide was developed by coating polythionine / nafion on a glassy carbon electrode. This sensor exhibited a great enhancement to the oxidation of nitric oxide. The oxidation peak currents were linear to the concentration of nitric oxide over the wide range from 3.6×10-7 to 6.8×10-5 mol.L-1, and the detection limit was 7.2×10-8 mol.L-1. Experimental results showed that this nitric oxide sensor possessed excellent selectivity and longer stability. NO releasing from rat kidney was monitored by this sensor.     

A Novel Tetraiodocadmate(Ⅱ)–PVC Membrane Electrode for the Potentiometric Determination of Cadmium(Ⅱ)

Cadmium is one of the most toxic heavy metal pollutants, so its determination is important. Carrier-based ion-selective electrodes (ISEs) have found wide application for being simple and economical. However, there are only limited reports on the ion-selec…     

Synthesis,Structures and Properties of Polyimide Based on 2,2′‐Bis(4‐aminophenoxy phenyl) Propane

2,2‐Bis[4‐(4‐aminophenoxy)phenyl] propane (BAPP), as a monomer to prepare polyimide, was synthesized from Bisphenol A and p‐chloronitrobenzene via the nucleophilic substitution reaction. The structures of the diamine monomer BAPP and an intermediate dinitrocompound 2,2′‐bis(4‐nitrophenoxy phenyl) propane (BNPP) were confirmed by FTIR and NMR. A novel polyimide was derived from BAPP and 3,3′,4,4′‐oxydiphthalic dianhydride (ODPA) in DMAc by a two‐step method. FTIR, DSC, TGA, and DMA were employed to characterize the precursor and the polyimide. The glass transition temperature of the polyimide was about 225–230°C. The measurement of mechanical properties indicated that the polyimide exhibited a typical yield behavior of thermoplastic polymers, which is very different from other polyimides. The elongation at break of the polyamic acid and polyimide was 6% and 29%, respectively.     

Fe(III) Ion‐Selective Membrane Electrode Based on 4‐Amino‐6‐methyl‐3‐methylmercapto‐1,2,4‐triazin‐5‐one

Abstract

An original highly selective and sensitive PVC membrane sensor, working as a Fe(III) ion selective electrode and using 4‐amino‐6‐methyl‐3‐methylmercapto‐1,2,4‐triazin‐5‐one (AMMTO) as an ionophore, has been developed. This cetain sensor demonstrated the following performance; a linear dynamic range between 1.0×10^?6 and 1.0×10^?1 M with a near Nernstian slope of 19.4±0.5 mV per decade; a detection limit of 6.8×10^?7 M; characteristically, the best performance was obtained with a membrane composition of 30% poly(vinyl chloride), 65.5% nitrophenyl octyl ether, 2% sodium tetraphenyl borate and 2.5% AMMTO. Furthermore, the potentiometric response of the developed electrode is independent of the solution pH in the range of 2.2–4.8. The sensor possesses the advantages of short conditioning time, fast response time (<15 s) and, especially, great selectivity towards transition and heavy metal ions and some mono, di‐ and trivalent cations. The electrode can be used for at least 9 weeks without any considerable potential divergence. It was effectively used as an indicator electrode in the potentiometric titration of Fe(III) ions with EDTA and the direct determination of Fe³⁺ in different water samples.     

Highly Selective and Sensitive Triiodide PVC‐Based Membrane Electrode Based on a New Charge Transfer Complex of 2‐(((2‐(((E)‐1‐(2‐Hydroxyphenyl) Methylidine) Amino) Phenyl) Imino) Methyl) Phenol for Nano‐Level Monitoring of Triiodide

Abstract

A highly selective and sensitive triiodide sensor based on a 2‐(((2‐(((E)‐1‐(2‐hydroxy phenyl) methylidine) amino) phenyl) imino) methyl) phenol with iodine (CTC) as membrane carrier was developed. The electrode revealed a Nernstian behavior over a very wide triiodide‐ion concentration range (5.0×10^?8–1.0×10^?2 M), and relatively low detection limit (3.0×10^?8 M). The potentiometric response is independent of the pH of solution in the pH range of 3.0–10.0. The electrodes manifest advantages of low resistance, very fast response (<12 s), and most importantly, good selectivities relative to a wide variety of inorganic and organic anions, including iodide, bromide, chloride, fluoride, sulfite, sulfate, cyanide, thiocyanate, and acetate. In fact, the selectivity behavior of the proposed triiodide ion‐selective electrode shows great improvements compared to the previously reported electrodes for the triiodide ion. The proposed membrane sensor can be used for at least 6 months without any significant divergences in the potential. The electrode was successfully applied as an indicator electrode in the titration of triiodide with thiosulfate ion.     

Synthesis of Novel Bis(mesocyclic) polyamines

介绍了带羟基桥连双－（中环多胺）的合成。首先利用Ｎ－对甲苯磺酰基－３－羟基－１，５－二氮杂环庚烷与５种双官能基化合物在Ｎ２气氛下于无水乙腈中反应，得到５种带对甲苯磺酰基的中环多胺，然后利用ＨＢｒ／ＨＯＡｃ脱去保护基团，得到桥连双－（中环多胺）的氢溴酸盐。所有新化合物的结构均经ＩＲ、１ＨＮＭＲ、ＭＳ或元素分析证实。     

A Novel Proton Sensor with Luminescence and Color Signaling Based on Platinum（Ⅱ） Terpyridyl Acetylide Complex

A novel sensitive probe for proton based on platinum(Ⅱ) terpyridyl acetylide complex by monitoring the changes both in luminescence and color is described.     

Application of Novel Praseodymium (III) PVC‐Membrane Electrode for Determination of Pr(III) Ions in Soil and Sediment Samples

Abstract

A novel Pr(III) ion‐selective polyvinyl chloride (PVC) membrane sensor, based on N,N‐bis(α‐methylsalicylidene)diethylenetriamine (BMT) as a new ionophore, has been prepared and studied. The electrode showed good selectivity for Pr(III) ion with respect to most common cations, including alkali, alkaline earth, transition, and heavy metal ions. This electrode has a wide linear dynamic range from 1.0×10^?6 to 1.0×10^?2 M with a Nernstian slope of 19.8±0.2 mV per decade and a low detection limit of 6.5×10^?7 M, in the pH range of 3.0–8.4, while response time was rapid (<15 s). As far as applications of the recommended sensor are concerned, first it was employed as an indicator electrode in the potentiometric titration of Pr(III) ions with EDTA. Second, it was effectively applied to the determination of concentration of Pr(III) ions in soil and sediment samples, and validation with CRMs.     

A Dicyanamido-bridged Zinc(Ⅱ) Complex Based on the Bis(4-pyridyl)ethane with a Three-dimensional Framework

A novel dicyanamido-bridged 3D polymeric complex {[Zn2(bpa)2(dca)]dca}n (1) (dca = dicyanamide anion,bpa = 1,2-bis(4-pyridyl)ethane) has been synthesized by reacting 1,2-bis(4-pyridyl)ethane with zinc salt in the presence of sodium dicyanamide,and characterized by elemental analysis,IR spectra and X-ray diffraction. It crystallizes in the monoclinic system,space group C2/c with a = 18.587(3),b = 20.070(3),c = 8.7957(13) ,β = 100.611(2)o,V = 3225.0(8) 3,Mr = 539.92,μ = 0.789 mm-1,F(000) = 1116,Z = 4,ρ = 1.112 (g/cm3),R = 0.0582 and wR = 0.1762. Complex 1 forms a 3D porous framework through the bpa and dca ligands,and gives 1-D coordination channels encapsulated by the guest dca molecules. Complex 1 also displays strong photo-luminescent properties in the solid state at room temperature.     

A Novel Sensitive Method for the Determination of Cadmium and Lead Based on Magneto‐Voltammetry

Abstract

A novel method for the ultratrace determination of Cd²⁺ and Pb²⁺ based on magneto‐voltammetry was developed. In the presence of a low strength magnetic field of 0.6 T, square wave stripping voltammetry (SWSV) of Cd²⁺ and Pb²⁺ was performed in this determination. A high concentration of redox species Fe³⁺ was added to the analytes to generate a large cathodic current during the preconcentration step. A large Lorentz force arising from the flux of net current through the magnetic field resulted in convective solution flow due to magnetohydrodynamics. Then more metal ions deposited on the electrode surface at a faster rate and an enhancement as large as 160% for the stripping peak current was observed. Under the optimal conditions, this method exhibits high sensitivities of 5.67 µA µM^?1 for Cd²⁺ and 6.98 µA µM^?1 for Pb²⁺, over the 1×10^?8 – 1×10^?6 mol l^?1 range. Detection limits as low as 9.0×10^?10 and 8.6×10^?10 mol l^?1 for Cd²⁺ and Pb²⁺ were obtained with a 2 min preconcentration time, respectively. The method was successfully applied to detect Cd²⁺ and Pb²⁺ in real water samples and the results were in agreement with atomic absorption spectrometry.     

Determination of Reduced Nicotinamide Adenine Dinucleotide Based on Immobilization of Tris(2,2′‐bipyridyl) Ruthenium(II) in Multiwall Carbon Nanotubes/Nafion Composite Membrane

Abstract

An electrochemiluminescence (ECL) method for reduced nicotinamide adenine dinucleotide (NADH) was proposed by immobilizing tris(2,2′‐bipyridyl) ruthenium(II) (Ru(bpy)₃ ²⁺) in multiwall carbon nanotubes (MWCNTs)/Nafion composite membrane that was formed on glassy carbon electrode surface. The electrochemical and ECL behaviors of the immobilized Ru(bpy)₃ ²⁺ were investigated. The cyclic votammogram of the modified electrode in pH 7.0 phosphate buffer solution showed a couple of redox peaks at +1190 and +1060 mV at 100 mV/s. The composite film had a more open structure and a large surface area allowing faster diffusion of Ru(bpy)₃ ²⁺. The presence of MWCNTs resulted in the improved ECL sensitivity and longer‐term stability of the modified electrode. The modified electrode showed a linear response to NADH in the concentration range of 1.0×10^?6 to 1.6×10^?5 M with a detection limit of 8.2×10^?7 M.     

Novel Supports Based on Polysaccharides for Sustained‐Release of Isosorbide Dinitrate

Novel supports based on carboxymethylcellulose (CMC), crosslinked with epichlorohydrin (EPC), and microparticles based on acetylphthalylcellulose (APC), for sustained‐release of isosorbide dinitrate (Isoket, Ik), were obtained. The drug has been included into CMC hydrogels through diffusion from ethanol‐water solution. Studies about the ethanol–water ratio influence on including the drug have shown an increased amount of included drug at higher content of water in the alcohol‐water mixture. Isoket–ACP microparticles have been obtained by drug and polymer co‐precipitation from emulsified aqueous solution.

The kinetics for “in vitro” release of Ik from polymeric materials, in simulated conditions for intestinal tract medium, where the drug is preferentially absorbed, has been analyzed. The experimental data have shown a “zero” order kinetic for drug release, which is characteristic for systems controlled by diffusion.     

A Novel Two-dimensional Homochiral Zinc（II） Complex Constructed Based on In Situ Ligand Formation

A novel zinc(Ⅱ) complex, Zn(IBT) 2 (1, HIBT=5-(4-((1H-imidazol-1-yl)methyl)phenyl)-2H-tetrazole) has been synthesized with Zn(NO3)2·6H2O, 4-(imidazol-1-ylmethyl)benzonnitrile (IBN) and NaN 3 by the hydrothermal method, and characterized by elemental analysis, IR and single-crystal X-ray diffraction. Crystallographic data for 1:C22H18N12Zn, Mr=515.85, orthorhombic, Pbcn, a=16.0567(15), b=9.5316(9), c=14.6107(14) , V=2236.1(4)  3 , Z=4, D c=1.532 g/cm3 , μ=1.138 mm-1 , F(000)=1056, R=0.0350 and wR=0.0888 for 1438 observed reflections (I > 2σ(I)) and the goodness-of-fit S=1.002 on F2 . The crystal structural analysis revealed that complex 1 exhibits a rare two-dimensional homochiral wave-like layer structure. In addition, the photoluminescence of complex 1 was studied in the solid state at room temperature together with its theoretical analysis.