3D nanostructured Ni(OH)2 microspheres as an efficient immobilization matrix of Ru(bpy)3 for high-performance electrochemiluminescence sensor

The electrochemistry and electrochemiluminescence (ECL) of novel three-dimensional nanostructured Ru(bpy)₃²⁺/Ni(OH)₂ microspheres were investigated for the first time. The negatively charged porous Ni(OH)₂ microspheres composed of Ni(OH)₂ nanowires were specifically designed to interact with Ru(bpy)₃²⁺. The large surface area and porous structure of Ni(OH)₂ microspheres enhance loading of Ru(bpy)₃²⁺ and mass transport of the model analyte, tripropylamine (TPA). Excellent ECL performance of the presented sensor was achieved including good stability and wide linear range from 7.7 × 10⁻¹⁰ to 3.8 × 10⁻³ M with the detection limit of 2.6 × 10⁻¹⁰ M to TPA.     

Solid-state electrochemiluminescence sensor through the electrodeposition of Ru(bpy)3/AuNPs/chitosan composite film onto electrode

Tris(2,2′-bipyridyl)ruthenium(II) (Ru(bpy)₃²⁺) has been successfully immobilized onto electrode through the electrodeposition of Ru(bpy)₃²⁺/AuNPs/chitosan composite film. In the experiments, chitosan solution was first mixed with Au nanoparticles (AuNPs) and Ru(bpy)₃²⁺. Then, during chronopotentiometry experiments in this mixed solution, a porous 3D network structured film containing Ru(bpy)₃²⁺, AuNPs and chitosan has been electrodeposited onto cathode due to the deposition of chitosan when pH value is over its pK_a (6.3). The applied current density is crucial to the film thickness and the amount of the entrapped Ru(bpy)₃²⁺. Additionally, these doping Ru(bpy)₃²⁺ in the composite film maintained their intrinsic electrochemical and electrochemiluminescence activities. Consequently, this Ru(bpy)₃²⁺/AuNPs/chitosan modified electrode has been used in ECL to detect tripropylamine, and the detection limit was 5 × 10⁻¹⁰ M.     

Multi-walled carbon nanotubes and Ru(bpy)3/nano-Au nano-sphere as efficient matrixes for a novel solid-state electrochemiluminescence sensor

An effective method for immobilization of Ru(bpy)₃²⁺ on glassy carbon electrode surface (GCE) is developed for the preparation of a novel electrochemiluminescence sensor. First of all, the positively charged Ru(bpy)₃²⁺ is modified on the surface of negatively charged gold nanoparticles (nano-Au) via the electrostatic interactions to obtain the Ru(bpy)₃²⁺/nano-Au nano-sphere (abbreviate as Ru-AuNPs). Subsequently, the large amount of Ru-AuNPs are immobilized on the multi-wall carbon nanotubes (MWCNTs)-Nafion homogeneous composite coated GCE by dual interaction: firstly, the Nafion, a kind of typical cation-exchange membrane, can absorb the Ru-AuNPs as the enrichment of cation Ru(bpy)₃²⁺ on the Ru-AuNPs surface; secondly, the employment of carboxylic MWCNTs in the Nafion film can also chemosorb the Ru(bpy)₃²⁺ cation on the Ru-AuNPs surface to increase the carrier content. At the same time, the experiment confirms that the enhancement of the ECL intensity on the sensor is attributed to following reasons. One hand, the employment of MWCNTs in the Nafion film enlarged the electro-active surface areas to benefit the contact between the signal probe on the composite film and coreactant used as reinforcing agent. On the other hand, the nano-materials of MWCNTs and nano-Au also improve the conductivity of the assembled film to increase the quantity of excited state of Ru(bpy)₃²⁺ in the unit time under the electrochemical condition and finally cause better properties in luminescence. In the experiment, the influence of the coreactant tripropylamine (TPA) on proposed ECL sensor is investigated. The logarithm of ECL intensity is proportional to the logarithm of TPA concentration on the range of 4 × 10⁻¹⁰ M to 2.8 × 10⁻⁶ M and 2.8 × 10⁻⁶ M to 0.71 × 10⁻³ M. After optimizing these conditions, the ECL sensor with TPA as coreactant is employed to detect a kind of alkaloid medicine, Matrine, for evaluating the practical application in the medicine analysis. The present sensor with TPA as coreactant shows the good response to the medicine concentration of the Matrine from 2.0 × 10⁻⁶ M to 6.0 × 10⁻³ M, which is used to detect the Matrine concentration in the Matrine injection.     

Can clay emit light? Ru(bpy)3-modified clay colloids and their application in the detection of glucose

In this paper, we describe the electrochemiluminescent (ECL) behavior of Ru(bpy)₃³⁺-incorporated clay colloids. Experimental results based on the electrochemical-quartz-crystal-microbalance (EQCM) techniques showed that Ru(bpy)₃³⁺ could be adsorbed by the clay colloids (montmorillonite K10, denoted K10). The resulting clay particles could emit light (λ_em 610 nm) when they were fabricated as thin films sandwiched by two conductive ITO electrodes with opposite biases. These Ru(bpy)₃³⁺-incorporated clay-modified electrodes could also emit light in aqueous oxalate solutions (pH 10) when potentials more positive than 0.9 V vs. SCE were applied. EDTA was an effective promoter for the Ru(bpy)_{3 (clay)}³⁺-oxalate ECL reaction. The resulting ECL showed a remarkable sensitivity to oxygen. A glucose optrode was thus fabricated based on the Ru(bpy)₃³⁺-incorporated K10 colloids and glucose oxidase (GOx). The ECL signals behaved as a function of [glucose], covering a range from 0.1 to 10 mM at pH 10. The detection limits reached a level of 0.1 mM at this pH.     

CdTe-Ru(bpy)32 体系阴极电致化学发光法测定邻苯二酚

根据邻苯二酚对CdTe量子点增敏的Ru(bpy)3₂ 阴极电致化学发光的强度有较强的抑制作用,建立了一种简单的测定邻苯二酚的电致化学发光(ECL)分析方法。实验依次探究了磷酸盐缓冲溶液的浓度、pH值、量子点的浓度、Ru(bpy)3₂ 的浓度、扫描速率以及电位等因素对该体系发光行为的影响。在最佳实验条件下,电致化学发光强度的对数与邻苯二酚浓度的对数在7.0×10_?8～4.0×10_?5 mol L_?1范围内呈现良好的线性关系,检出限为2.3×10_?8 mol L_?1(3σ)。对4.0×10_?6 mol L_?1的邻苯二酚标准溶液进行六次平行测定,其电致化学发光强度的相对标准偏差(RSD)为1.1 %。进一步,该方法可成功应用于模拟环境水样中邻苯二酚的含量测定,加标回收率介于95.0～105.7 %之间。     

A fiber-optic evanescent wave sensor for dissolved oxygen detection based on novel hybrid fluorinated xerogels immobilized with [Ru(bpy)3]2+

We have prepared a novel fiber-optic evanescent wave sensor (FEWS) for dissolved oxygen (DO) detection. The sensor fabrication was based on coating a decladded portion of an optical fiber with a microporous coating, which was prepared from 3,3,3-trifluoropropyltrimethoxysilane and n-propyltrimethoxysilane. The fluorophores were immobilized in the porous coating and excited by the evanescent wave field produced on the core surface of the optical fiber. The sensitivity of the sensor was quantified by the ratio of the fluorescence intensities in pure deoxygenated (I ₀) and in pure oxygenated environments (I). Results show that the quenching response of DO is increased with the enhancement of the coating surface hydrophobicity using the presented hybrid fluorinated ORMOSILs. The calibration curve of I ₀/I to [O₂] is linear from 0 to 40 ppm and the detection limit is 0.05 ppm (3σ) with a short response time of 15 s for DO detection. Figure       

Determination of itopride hydrochloride by high-performance liquid chromatography with Ru(bpy)3 electrogenerated chemiluminescence detection

In this work, a stable electrogenerated chemiluminescence (ECL) detector was developed. The detector was prepared by packing cation-exchanged resin particles in a glass tube, followed by inserting Pt wires (working electrode) in this tube and sealing. The leakage of Ru(bpy)₃²⁺ can be compensated by adding a small amount of Ru(bpy)₃²⁺ into solution phase. Coupled with high-performance liquid chromatography separation, the detector has been used for determination of itopride hydrochloride in human serum. Under the optimal conditions, the ECL intensity has a linear relationship with the concentration of itopride hydrochloride in the range of 1.0 × 10⁻⁸ g mL⁻¹ to 1.0 × 10⁻⁶ g mL⁻¹ and the detection limit was 3 × 10⁻⁹ g mL⁻¹ (S/N = 3). The as-prepared ECL detector displayed good sensitivity and stability.     

玻碳电极上Ru(bpy)32+的吸附及其电致化学发光的研究

通过电化学循环伏安法和电致化学发光方法, 研究了Ru(bpy)₃²⁺在玻碳电极上的吸附, 研究结果表明, Ru(bpy)₃²⁺的浓度和与玻碳材料接触的时间, 直接影响了Ru(bpy)₃²⁺在玻碳上的吸附. 还考察了吸附的 在玻碳电极上被氧化后脱附的情况.     

A novel amperometric sensor for the detection of difenidol hydrochloride based on the modification of Ru(bpy)3 on a glassy carbon electrode

An amperometric sensor for the detection of difenidol, a tertiary amine-containing analyte, was proposed. Ruthenium(II) tris(bipyridine)/multi-walled carbon nanotubes/Nafion composite film was suggested to modify the glassy carbon electrode. The modified electrode was shown to be an excellent amperometric sensor for the detection of difenidol hydrochloride. The linear range is from 1.0 × 10⁻⁶ to 3.3 × 10⁻⁵ M with a correlation coefficient of 0.998. The limit of detection was 5 × 10⁻⁷ M, which was obtained through experimental determination based on a signal-to-noise ratio of three. The sensor was employed to the determination of the active ingredients in the tablets containing difenidol hydrochloride.     

纳米银粒子对[Ru(bpy)_3]~(2+)光谱学性质的影响及电解质效应

研究了[Ru(bpy)3]2+溶液中引入纳米银粒子的光谱学性质变化规律以及[Ru(bpy)3]2+与纳米银粒子所构成的溶液体系([Ru(bpy)3]2+-Ag)的电解质效应.研究结果表明,[Ru(bpy)3]2+吸附在纳米银粒子表面使纳米银粒子相互桥连形成规则的类链状网络聚集体.纳米银粒子造成[Ru(bpy)3]2+溶液荧光猝灭,且大尺寸的纳米银粒子引起的荧光猝灭程度较大.在[Ru(bpy)3]2+-Ag体系中引入电解质造成纳米银粒子不同程度的聚集和生长.电解质对纳米银聚集影响为:CaCl2MgCl2Ca(NO3)2KClKNO3.随着[Ru(bpy)3]2+-Ag体系中引入电解质含量的增加,溶液的荧光强度先降低而后又逐渐增强,直至达到定值,表明一定量的电解质可产生荧光猝灭释放效应.电解质对荧光强度影响顺序为:Ca(NO3)2CaCl2MgCl2KClKNO3.采用透射电子显微镜、紫外-可见吸收分光光度计和荧光分光光度计等手段从分子间相互作用和能量传输等方面初步探讨了纳米银粒子对表面吸附[Ru(bpy)3]2+溶液光谱学性质的影响机制以及电解质效应.     

Electrochemiluminescence immunosensor for ultrasensitive detection of biomarker using Ru(bpy)3-encapsulated silica nanosphere labels

Here, we describe a new approach for electrochemiluminescence (ECL) assay with Ru(bpy)₃²⁺-encapsulated silica nanoparticle (SiO₂@Ru) as labels. A water-in-oil (W/O) microemulsion method was employed for one-pot synthesis of SiO₂@Ru nanoparticles. The as-synthesized SiO₂@Ru nanoparticles have a narrow size distribution, which allows reproducible loading of Ru(bpy)₃²⁺ inside the silica shell and of α-fetoprotein antibody (anti-AFP), a model antibody, on the silica surface with glutaraldehyde as linkage. The silica shell effectively prevents leakage of Ru(bpy)₃²⁺ into the aqueous solution due to strong electrostatic interaction between the positively charged Ru(bpy)₃²⁺ and the negatively charged surface of silica. The porous structure of silica shell allowed the ion to move easily through the pore to exchange energy/electrons with the entrapped Ru(bpy)₃²⁺. The as-synthesized SiO₂@Ru can be used as a label for ultrasensitive detection of biomarkers through a sandwiched immunoassay process. The calibration range of AFP concentration was 0.05-30 ng mL⁻¹ with linear relation from 0.05 to 20 ng mL⁻¹ and a detection limit of 0.035 ng mL⁻¹ at 3σ. The resulting immunosensors possess high sensitivity and good analytical performance.     

十二烷基磺酸钠-盐酸维拉帕米-联吡啶钌体系电化学发光及其应用

在十二烷基磺酸钠(SDS)中,考察了盐酸维拉帕米-Ru(bpy)3(2+)体系在金电极上的电化学及其发光行为.结果表明:SDS对体系的电化学反应和电化学发光强度具有显著的增敏作用.据此,建立了一种高效、简便的测定盐酸维拉帕米的电化学发光新方法.在最佳实验条件下,盐酸维拉帕米浓度在1.0×10(-4)～1.0×10(-2...     

Ru(bpy)_3 掺杂的核壳型 Ag@SiO_2 荧光纳米粒子的制备及表征

利用反相微乳液法制备了一种三联吡啶钌掺杂的核壳型Ag@SiO2纳米粒子。利用透射电子显微镜、荧光光谱和紫外-可见光谱等对其进行表征,并对其光稳定性和表面氨基进行了测定,结果表明该纳米粒子单分散性良好,呈规则球状、粒径为(60±5)nm,由于银的金属增强荧光效应,相对没有银核的Ru(bpy)3掺杂的SiO2纳米粒子,其荧光强度增强了2倍,光稳定性也有所提高。     

Spectroscopic and photoelectrochemical differences between racemic and enantiomeric [Ru(phen)3] ions intercalated into layered niobate K4Nb6O17

Chirality effects have been observed in the intercalation, spectroscopic and photoelectrochemical behavior when enantiomeric and racemic [Ru(phen)₃]²⁺ complexes were intercalated in the interlayer spaces of K₄Nb₆O₁₇. The results were interpreted in terms of a [Nb₆O₁₇]⁴⁻-chelate and chelate–chelate interactions. The faster luminescence decay and higher photocurrent of the enantiomeric [Ru(phen)₃]²⁺–K₄Nb₆O₁₇ compounds than the racemic ones suggest that the emission of adsorbed [Ru(phen)₃]²⁺ ions was not only quenched by adsorbed complexes (or concentration quenching) but also by the semiconductive host lattices.     

Determination of indole-3-acetic acid and indole-3-butyric acid in mung bean sprouts using high performance liquid chromatography with immobilized Ru(bpy)3-KMnO4 chemiluminescence detection

A novel method for determination of indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) in an extract from mung bean sprouts using high performance liquid chromatography (HPLC) with chemiluminescence (CL) detection is described. The method is based on the CL reaction of auxin (indole-3-acetic acid and indole-3-butyric acid) with acidic potassium permanganate (KMnO₄) and tris(2,2′-bipyridyl)ruthenium(II), which was immobilized on the cationic ion-exchange resin. The chromatographic separation was performed on a Nucleosil RP-C18 column (i.d.: 250 mm × 4.6 mm, particle size: 5 μm, pore size: 100) with an isocratic mobile phase consisting of methanol-water-acetic acid (45:55:1, v/v/v). At a flow rate of 1.0 mL min⁻¹, the total run time was 20 min. Under the optimal conditions, the linear ranges were 5.0 × 10⁻⁸ to 5.0 × 10⁻⁶ g mL⁻¹ and 5.0 × 10⁻⁷ to 1.0 × 10⁻⁵ g mL⁻¹ for IAA and IBA, respectively. The detection limits were 2.0 × 10⁻⁸ g mL⁻¹ and 2.0 × 10⁻⁷ g mL⁻¹ for IAA and IBA, respectively. The relative standard deviation (RSD) of intra-day were 3.1% and 2.3% (n = 11) for 2 × 10⁻⁶ g mL⁻¹ IAA and 2 × 10⁻⁶ g mL⁻¹ IBA; The relative standard deviations of inter-day precision were 6.9% and 4.9% for 2 × 10⁻⁶ g mL⁻¹ IAA and 2 × 10⁻⁶ g mL⁻¹ IBA. The proposed method had been successfully applied to the determination of auxin in mung bean sprouts.     

Determination of sulfur contents of SO3, S2O3 and S based on the electrocatalytic interaction with homogeneous mediator tris(2,2'-bipyridyl)Ru(II)

A sensitive voltammetric method has been developed for the determination of total or single species of sulfur anions containing sulfide, sulfite and thiosulfate. The method is based on the catalytic effect of tris(2,2'-bipyridyl)Ruthenium(II) (Ru(bpy)₂^+ 2) as a homogeneous mediator on the oxidation of those anions at the surface of a glassy carbon electrode. A reversible redox couple of Ru(II)/Ru(III) were observed as a solute in aqueous solution. Cyclic voltammetry study showed that the catalytic current of the system depends on the concentration of the anions. Optimum pH values for voltammetric determination of sulfite, thiosulfate and sulfide has been found to be 5.6, 10.0 and 10.0, respectively. Under the optimized conditions the calibration curves have been obtained linear in the concentration ranges of 0.8–500.0, 0.4–1000.0 and 0.5–5000.0 µmol L^− 1 of SO₃²⁻, S₂O₃²⁻ and S²⁻, respectively. The detection limits have been calculated to be 0.40, 0.17 and 0.33 µmol L^− 1 for SO₃²⁻, S₂O₃²⁻ and S²⁻, respectively. The diffusion coefficients of sulfite and thiosulfate have been estimated using chronoamperometry. The chronoamperometric method also has been used to determine the catalytic rate constant for catalytic reaction of the Ru(bpy)₂^+ 2 with sulfite and thiosulfate. Finally the proposed method has been used for the determination of total sulfur contents in real samples of water and wastewater. Moreover the sulfite content in sugar and sulfur dioxide in air has been determined with satisfactory results.     

Modulated potential electrogenerated chemiluminescence of luminol and Ru(bpy) 3 2+

Chemiluminescence emission intensity is modulated by modulating the potential of a working electrode which is used to generate a key species in the electrogenerated Chemiluminescence (ECL) reaction. The emission is monitored synchronously using a lock-in amplifier. The reactions used in the characterization are luminol with hydrogen peroxide and tris(2,2-bipyridyl)ruthenium (II) (or Ru(bpy) ₃ ²⁺ ) with oxalate. Modulation widths of ± 50 mV yield maximum signals for luminol when centered at 0.45 V (vs Ag/AgCl) and for Ru(bpy) ₃ ²⁺ when centered at 1.05 V. The resulting signal decreases with increasing modulation frequency and shows that luminol/H₂O₂ is a faster ECL system than Ru(bpy) ₃ ²⁺ /oxalate. Working curves for luminol and for oxalate have essentially the same linear range and slope with the modulated potential approach as with a DC electrode potential. This approach provides capability for differentiating the analytical signal from constant background emission or stray light.     

IR and Raman spectra of two layered aluminium phosphates Co(en)3Al3P4O16 · 3H2O and [NH4]3[Co(NH3)6]3[Al2(PO4)4]2 · 2H2O

The FT IR and FT Raman spectra of Co(en)₃Al₃P₄O₁₆ · 3H₂O (compound I) and [NH₄]₃[Co(NH₃)₆]₃[Al₂(PO₄)₄]₂ · 2H₂O (compound II) are recorded and analysed based on the vibrations of Co(en)₃³⁺, Co(NH₃)₆³⁺, NH₄⁺, Al---O---P, PO₃, PO₂ and H₂O. The observed splitting of bands indicate that the site symmetry and correlation field effects are appreciable in both the compounds. In compound I, the overtone of CH₂ deformation Fermi resonates with its symmetric stretching vibration. The NH₄ ion in compound II is not free to rotate in the crystalline lattice. Hydrogen bonding of different groups is also discussed.     

Nafion负载的三联吡啶钌为敏化剂烯烃的光敏氧化反应

以[Ru(bpy)_3]~(2+)和Nafion膜负载的[Ru(bpy)_3]~(2+)为敏化剂，研究了反 式－1，2－二甲氧基芪、2，3－二氢吡喃和反式，反式－1，4－二苯基，3－丁二 烯在甲醇中的光敏氧化。实验表明，与均相光敏氧化相比，Nafion负载的敏化剂具 有敏化剂与产物、剩余底物、溶济等易分离并可重复使用的优点。     

Spectroscopic properties of guanidinium zinc sulphate [C(NH2)3]2Zn(SO4)2 and ab initio calculations of [C(NH2)3]2 and HC(NH2)3

Raman and FTIR spectra of guanidinium zinc sulphate [C(NH₂)₃]₂Zn(SO₄)₂ are recorded and the spectral bands assignment is carried out in terms of the fundamental modes of vibration of the guanidinium cations and sulphate anions. The analysis of the spectrum reveals distorted SO₄²⁻ tetrahedra with distinct S–O bonds. The distortion of the sulphate tetrahedra is attributed to Zn–O–S–O–Zn bridging in the structure as well as hydrogen bonding. The CN₃ group is planar which is expressed in the twofold symmetry along the C–N (1) vector. Spectral studies also reveal the presence of hydrogen bonds in the sample. The vibrational frequencies of [C(NH₂)₃]₂ and HC(NH₂)₃ are computed using Gaussian 03 with HF/6-31G* as basis set.