The electrogenerated chemiluminescent behavior of hemin and its catalytic activity for the electrogenerated chemiluminescence of lucigenin

The electrogenerated chemiluminescent (ECL) behavior of hemin at a platinum electrode in the alkaline solution has been investigated in detail. Under the optimum conditions the linear response range of hemin is 1.0×10⁻⁵–1.0×10⁻⁸ g ml⁻¹, the detection limit was 1.0×10⁻⁸ g ml⁻¹, and the relative standard derivation for 1×10⁻⁷ g ml⁻¹ hemin was 2.8%. It has been also found that hemin would catalyze the ECL of lucigenin at a platinum electrode in a neutral solution in the presence of hydrogen peroxide, the catalytic ECL intensity was linear with the concentration of hemin in the range of 1.0×10⁻¹⁴–1.0×10⁻¹⁰ g ml⁻¹. IgG labeled with hemin was used to examine the ECL catalytic activity of hemin after conjugating to protein, and the results showed that hemin retained ECL catalytic activity when conjugated to protein.     

Time-resolved electrochemiluminescence of platinum(II) coproporphyrin

Cathodic pulse polarisation of oxide-covered aluminium electrodes can generate electrochemiluminescence (ECL) from metalloporphyrins. This is based on the tunnel emission of hot electrons into aqueous electrolyte solution, which probably results in the generation of hydrated electrons as reducing mediators. These tunnel emitted electrons allow the production of highly reactive radicals, such as sulfate radicals from peroxodisulfate ions, which can induce strong redox luminescence from various organic chemiluminophores including metalloporphyrins. The work presented here illustrates the generation of ECL from platinum(II) coproporphyrin (PtCP) and its bovine serum albumin (BSA) conjugate. This allows the detection of these molecules below nanomolar concentrations and over several orders of magnitude of concentration. The relatively long luminescence lifetime of PtCP allows discrimination from the background ECL signal using time resolved measurements, leading to higher sensitivity and the detection of PtCP-BSA indicates the potential use of metalloporphyrins as labels in ECL-based bioassays such as immunoassays and DNA-binding assays.     

CdTe量子点修布电极的阳极电致化学发光

制备了CdTe量子点/Nafion修饰玻碳电极(CdTe QDs/Nafion/GCE),并研究了该修饰电极在中性磷酸盐缓冲溶液(PBS)中的电致化学发光(ECL)行为.结果表明,三丙胺(TPA)作为共反应剂存在时,QDs/Nafion/GCE在中性PBS中可以产生强的阳极电化学发光信号.考察了量子点的用量、Nafion的用量、pH、电解质等条件对ECL的影响.抗坏血酸对QDs/Nafion/GCE的ECL具有抑制作用,且抑制程度与抗坏血酸浓度呈线性关系,为利用电致化学发光法检测抗坏血酸提供了新方法.     

Fabrication and Characterization of a Thin-Layer Electrochemical Flow Cell and Its Application for Flow Analysis

The design and fabrication of a home-made thin-layer electrochemical flow cell are reported. The performance and electrochemical characteristics of thin-layer cells are evaluated in terms of flow rate and channel thickness. The adaptability of the flow cell for amperometric and electrochemiluminescence measurements is demonstrated. Also, a flow injection method comprising electrochemical generation followed by spectrophotometric detection is proposed for determination of bromide using the fabricated cell. The influence of chemical, electrochemical, and flow parameters on the absorbance and current signals are investigated, and under optimized conditions, the analytical features of the proposed method with respect to bromide detection are evaluated.     

Enhanced Sensitivity of the Tris(Bipyridine)Ruthenium(II) Chloride Electrogenerated Chemiluminescence Sensor with Porous Silica Nanoparticles

Mass transfer in electrogenerated chemiluminescence affects the sensitivity of sensors involving this technique. Herein, the characteristics of the porous Ru(bpy)₃²⁺/silica nanoparticles were investigated by transmission electron microscopy, fluorescence spectroscopy, ultraviolet-visible absorption spectroscopy, and electrogenerated chemiluminescence. The results showed that the pores inside the porous nanoparticles provided efficient mass transfer, resulting in significant enhancement of electrogenerated chemiluminescence. Consequently, a novel electrogenerated chemiluminescence sensor was developed and is reported herein. The sensitivity for tripropylamine was more than one order of magnitude higher compared to previously reported similar sensors, with a limit of detection of 3.3 × 10^?12 moles per liter.     

基于工具酶信号放大技术电化学发光法检测凝血酶

利用巯基乙胺将合成的金纳米粒子氨基化;基于纳米粒子负载羧基化的联吡啶钌和巯基DNA制得电化学发光信号探针;采用酶循环信号放大技术,获得大量含新增DNA的溶液来捕获信号探针;以金电极为载体,将巯基DNA自组装到电极表面,依次杂交互补DNA和信号探针,构建电化学发光生物传感器.在优化的条件下,此传感器对凝血酶具有良好的响应,在3.0× 10-13～6.0×10-11 mol/L范围内,凝血酶的浓度与发光强度呈良好的线性关系,检出限为1.8× 10-13 mol/L(3a).采用酶切循环放大技术制备的生物传感器具有灵敏度高,选择性和重现性良好等特点.     

Enhancement of Electrochemiluminescence of Porous Silicon with Tri‐n‐propylamine as Co‐reactant

Visible light emission can be stimulated by applying a cyclic bias to a porous silicon/tri‐n‐propylamine (PS/TPrA) solid/liquid system. With the presence of 2.5 mM TPrA, the electrochemiluminescence intensity of the in situ formed PS electrode is 450 times higher than the blank solution. An applied voltage as low as 1.2 V is capable of generating light emission, indicating that current‐induced chemical reactions are an aid to the generation of charge carriers. A mechanism involving oxidation of TPrA followed by hole injection is proposed. The system also shows good ECL stability. In addition, the ECL emission can be inhibited by diphenols rather than phenol.     

Electrochemiluminescence from Ru(bpy)3 immobilized in poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate)-poly(vinyl alcohol) composite films

Electrochemical behavior and electrogenerated chemiluminescence (ECL) of tris(2,2′-bipyridyl)ruthenium(II) (Ru(bpy)₃²⁺) immobilized in poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate)-poly(vinyl alcohol) (PEDOT/PSS-PVA) composite films via ion-exchange have been investigated with tripropylamine (TPA) as the co-reactant at a glassy carbon electrode. The immobilized Ru(bpy)₃²⁺ performed a surface-controlled electrode reaction. The Ru(bpy)₃²⁺ modified electrode showed a fast ECL response to TPA, and was used for the ECL detection of TPA with high sensitivity. The ECL intensity was linearly related to concentrations of TPA over the range from 0.50 μmol L⁻¹ to 0.80 mmol L⁻¹, and the detection limit was 0.10 μmol L⁻¹ (S/N = 3). The as-prepared electrode exhibited good precision and long-term stability for TPA determination.     

A novel method developed for acetylcholine detection in royal jelly by using capillary electrophoresis coupled with electrogenerated chemiluminescence based on a simple reaction

A novel method for highly sensitive detection of acetylcholine in royal jelly was proposed by using CE coupled with electrogenerated chemiluminescence (ECL). Acetylcholine, which could not react with Tris(2,2′‐bipyridine)ruthenium(II) to strengthen its ECL signals, decomposed into trimethylamine and strengthened the ECL signals sharply when it was heated to its melting point. This reaction needed no additional reagent and it was mild, simple, stable and rapid, without any side reaction. By combining the above process with CE separation technique, trimethylamine in royal jelly was completely separated from interfering substances and was successfully detected within 4 min. The limit of detection for acetylcholine was found to be 6.3×10^?8 g/mL with a signal‐to‐noise ratio of 3:1. Acetylcholine in the royal jelly was detected to be 912±58 μg/g. The recoveries of acetylcholine chloride in the sample were in the ranges of 92–106%. The coefficients of variation for intra‐day and inter‐day reproducibility were equal to or less than 4.9 and 6.8%, respectively.     

A signal-on electrogenerated chemiluminescent biosensor for lead ion based on DNAzyme

A highly reproducible and sensitive signal-on electrogenerated chemiluminescence (ECL) biosensor based on the DNAzyme for the determination of lead ion was developed. The ECL biosensor was fabricated by covalently coupling 5′-amino-DNAzyme-tagged with ruthenium bis (2,2′-bipyridine) (2,2′-bipyridine-4,4′-dicarboxylic acid)-ethylenediamine (Ru1-17E′) onto the surface of graphite electrode modified with 4-aminobenzoic acid, and then a DNA substrate with a ribonucleotide adenosine hybridized with Ru1-17E′ on the electrode. Upon binding of Pb²⁺ to the Ru1-17E′ to form a complex which catalyzed the cleavage of the DNA substrate, the double-stranded DNA was dissociated and thus led to a high ECL signal. The signal linearly increases with the concentration of Pb²⁺ in the range from 5.0 to 80 pM with a detection limit of 1.4 pM and a relative standard derivation of 2.3%. This work demonstrates that using DNAzyme tagged with ruthenium complex as an ECL probe and covalently coupling method for the fabrication of the ECL biosensor with high sensitivity, good stability and significant regeneration ability is promising approach.