鲁米诺在铂电极上阳极电致化学发光的机理研究

研究了碱性鲁米诺溶液在多晶铂电极上的阳极电致化学发光(ECL)行为,观察到电极的预极化处理和溶解氧跟发光峰强度和峰形有直接关系。结合XPS谱图和Pt,Pt|S~a~d~s修饰电极的循环伏安特性,给出了鲁米诺阳极ECL两个发光通道的可能反应机理:(1)鲁米诺阴离子在表面有新鲜Pt原子的电极上氧化生成鲁米诺自由基,然后迅速与溶液中的氧反应形成0.22V(vs.Ag)处的发光肩峰;(2)电极表面的铂氧化物能加速原子态氧的发生过程,并增大0.60V(vs.Ag)附近ECL主峰的发光强度。     

罗丹明B的电致化学发光行为研究

研究发现罗丹明B在碱性溶液中铂电极上有较强的电致化学发光行为.通过对不同NaOH浓度,以及对不同支持电解质的考察,确定最佳电致化学发光条件.在最优条件下,在1.2×10-7~1.1×10-6mol/L浓度范围内,罗丹明B的电致化学发光强度与其浓度成线性关系,最低检测限为9.0×10-8mol/L(S/N=3).将罗丹明B同一些生物活性物质相配合,然后通过罗丹明B的ECL技术对生物活性物质进行检测.     

Ultrasonic enhancement of electrochemiluminescence from arylacetate electrooxidation

This paper describes the previously unreported electrogenerated chemiluminescence (ECL) from the electro-oxidation of several aryl carboxylates at a platinum flag electrode in aqueous, methanolic and acetonitrile solutions using tetramethylammonium hydroxides as a supporting electrolyte. In most cases electrochemiluminescence was markedly enhanced by simultaneous irradiation with ultrasound during electrolysis. Increase in electrochemiluminescence intensity with electrolysis current and carboxylate concentration was observed. Addition of a radical scavenger or purging of the solution with oxygen lowers ECL emission intensity. In contrast the presence of oxygen enhances the intensity of sonoluminescence, which is a concurrent but weaker process occurring under ultrasonic irradiation alone. Ring-substituted phenylacetates almost always produced less electrochemiluminescence than the unsubstituted parent molecule, though within the substituents studied chloro-substituted phenylacetates produced more ECL intensity than either methoxy- or nitro-substituted derivatives.     

Fiberoptic biosensors based on chemiluminescent reactions

The chemiluminescence of luminol in the presence of H₂O₂ has been exploited to develop fiberoptic biosensors associated with flow injection analysis systems. A chlorophenol sensor was developed based on the ability of certain halophenols to enhance the peroxidase-catalyzed luminol chemiluminescence. Horseradish peroxidase immobilized on a collagen membrane was used. Ten chlorophenols have been tested with this chemiluminescent-based sensor. The lower detection limit was obtained with 4-chloro-3-methylphenol and was equal to 0.01 μM. Electrochemiluminescent-based fiberoptic biosensors for glucose and lactate were also developed using glucose oxidase or lactate oxidase immobilized on polyamide membranes. In the presence of oxidase-generated H₂O₂, the light emission was triggered electrochemically by means of a glassy carbon electrode polarized at +425 mV vs a platinum pseudo-reference electrode. The detection limits for glucose and lactate were 150 and 60 pmol, respectively, and the dynamic ranges were linear from 150 pmol to 600 nmol and from 60 pmol to 60 nmol, respectively.     

流动注射电化学发光法测定半胱氨酸和谷胱甘肽

采用流动注射分析技术研究了半胱氨酸和谷胱甘肽对鲁米诺微弱电化学发光的增敏行为。对影响电化学发光的各因素进行了试验和探讨 ,提出了可能的反应机理 ,并建立一种电化学发光测定半胱氨酸和谷胱甘肽的新方法。半胱氨酸和谷胱甘肽的浓度在 1 .0× 1 0 - 6 mol/L～ 5 .0× 1 0 - 5 mol/L和 1 .0× 1 0 - 6mol/L～ 2 .0× 1 0 - 5 mol/L之间呈良好的线性关系 ,相关系数分别为 0 .993和0 998,检出限分别为 0 .67μmol/L和 0 .72 μmol/L。对 1 .0× 1 0 - 5mol/L的半胱氨酸和谷胱甘肽进行 1 1次平行测定 ,相对标准偏差分别为 4.5 %和 3.7%。     

An On—line Galvanic Cell Generated Electrochemiluminescence and Flow Injection Determination of Calcium in Milk and Vegetable

An on-line Ag/Al galvanic cell is investigated and employed to generate electrochemiluminescence(ECL).The potential of the galvanic cell could be adjusted by varying the components of flow reagent.The cell performed perfect capability of supplying a stable potential for ECL generation.Based on the weak ECL of calcein blue could be greatly sensitized by the presence of calcium in alkaline solution,calcium contents in milk samples and in cabbage were assayed and the results were compared with those from ICP-AES method.     

Tris(2,2'-bipyridyl)ruthenium(II)-zirconia-Nafion composite films applied as solid-state electrochemiluminescence detector for capillary electrophoresis

The major goal of this work was to develop a new solid-state electrochemiluminescence (ECL) detector suitable for capillary electrophoresis (CE). The detector was fabricated by coating a sol-gel derived zirconia (ZrO(2))-Nafion composite film on a graphite electrode, then the zirconia-Nafion modified electrode was immersed in tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)(3) (2+)) solution to immobilize this active chemiluminescence reagent. The voltammetric and ECL behaviors of the detector were investigated and optimized in tripropylamine solution. The ratio of 53% for zirconia in the zirconia-Nafion composite provided the highest luminescence intensity of immobilized Ru(bpy)(3) (2+). The ECL can maintain its stability very well in the phosphate solution in the period of 5-90 h when the solid-state ECL detector was immersed in the solution all the time. The optimum distance of capillary outlet to the solid-state ECL detector has been found to be ca. 50-80 microm for a 75 microm capillary. The effects of ionic strength and pH of ECL solution on peak height were investigated. The CE with solid-state ECL detector system was successfully used to detect tripropylamine, lidocaine, and proline. The detection limits (S/N = 3) were 5 x 10(-9) mol.L(-1) for tripropylamine, 1 x 10(-8) mol.L(-1) for lidocaine and 5 x 10(-6) mol.L(-1) for proline, and the linear ranges were from 1.0 x 10(-8) to 1.0 x 10(-5) mol.L(-1) for tripropylamine, 5.0 x 10(-7) mol.L(-1) to 1.0 x 10(-5) mol.L(-1) for lidocaine and 1.0 x 10(-5) to 1.0 x 10(-3) mol.L(-1) for proline, respectively.     

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.     

Facile Fabrication of Solid‐state Electrochemiluminescence Sensor via Non‐covalent π‐π Stacking and Covalent Bonding on Graphite Electrode

Herein, a facile and efficient method was developed for fabrication of solid‐state electrochemiluminescence (ECL) sensor via non‐covalent π‐π stacking and covalent bonding on the graphite electrode (GE) surface. The electrode was firstly modified with 1‐aminopyrene via π‐π stacking between GE surface and the pyrene moiety. Thereafter a stable and efficient solid‐state ECL sensor was fabricated by covalent immobilization of ruthenium(II) onto the GE surface via amidation reaction between the 1‐aminopyrene and bis(2,2′‐bipyridyl)(4‐methyl‐4′‐carboxypropyl‐2,2′‐bipyridyl) ruthenium(II) bishexafluorophosphate. The sensor has been investigated using tripropylamine and tetracycline as representative analytes, and low detection limits of 0.7 nM and 3.5 nM (S/N=3) were reached, respectively.     

Recent advances on the development of graphene-based field-effect transistors,electrochemical biosensors and electrochemiluminescence biosensors

Graphene, a honeycomb lattice of carbon material with single-atom-layer structure, demonstrates extraordinary mechanical, thermal, chemical and electronic properties. Thus, it has sparked tremendous interests in various fields, such as energy storage and conversion devices, field-effect transistors (FET), chemical sensors and biosensors. In this review, we will first focus on the synthesis method of graphene and the fabrication strategy of graphene-based materials. Subsequently, the construction of graphene-based biosensors are introduced, in which three kinds of biosensors are discussed in details, including the FET, electrochemical biosensors and electrochemiluminescence (ECL) biosensors. The performances of the state-of-the-art biosensors on the detection of biomolecules are also displayed. Finally, we also highlight some critical challenges remain to be solved and the development in this field for further research.