玻碳电极上Ru(bpy)23+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)23+在玻碳电极上的吸附,研究结果表明,Ru(bpy)23+的浓度和与玻碳材料接触的时间,直接影响了Ru(bpy)23+在玻碳上的吸附.还考察了吸附的Ru(bpy)23+在玻碳电极上被氧化后脱附的情况.     

玻碳电极上Ru（bpy）3^2＋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,2Ru(bpy)3 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Ru(bpy)32 在玻碳电极上被氧化后脱附的情况.     

联吡啶钌修饰电极固相电致化学发光

由于电致化学发光(ECL)的连续可测性、高灵敏度、稳定和方法简单,被广泛应用于分子生物学、药学、化学和环保等领域.而将可电化学再生的ECL试剂固定于电极表面,可获得ECL传感器,从而减少分析过程中试剂的消耗并简化实验装置.联吡啶钌及其衍生物在电极表面的固定化研究成为ECL研究的重要方向.本文综述了2004年以来联吡啶钌及其衍生物修饰电极的固相ECL的研究进展,并简要介绍了各种固定方法及其相关的应用情况.     

基于热控电极的电致化学发光传感器的研究进展

电致化学发光（ECL）检测技术因其具有无需激发光源、仪器简单、灵敏度高、选择性好等特点,被广泛应用于环境分析、生物分析等领域. 温度是影响ECL的主要因素之一,在传统的ECL传感器中大多是通过溶液整体加热的方法来控制温度,这种方法操作繁琐,且溶液中的热不稳定性物质及易挥发性物质容易受到影响,因此电极很少工作在最适宜的温度下. 热控电极技术可以只提高电极表面温度,而维持溶液的整体温度不变,使用起来具有很好的便利性. 作者课题组首次将热控电极引入到ECL传感器的构建中,由于电极表面和溶液之间存在一定的温度梯度,因此可以引发强制对流,从而加快物质的扩散和对流速率;电极表面温度的升高还可以进一步提高电极表面物质的电化学反应速率,这两方面的共同作用提高了ECL检测的灵敏度. 同时,利用热控电极可以解决整体加热所引起的背景信号升高,挥发性、热不稳定性物质易受温度影响等问题,而且通过电极加热的方法可去除电极表面的污染物,从而提高ECL检测的重现性. 本文综述了近年来基于热控电极技术的ECL传感器的研究进展,主要介绍了热控电极的加热方式、电极种类以及热控电极在ECL中的应用等,并分析了该技术在实际应用中面临的主要问题,对该技术未来的发展趋势进行了展望.     

氧化锌修饰铅笔芯电极电致化学发光法测定苯酚的研究

采用滴涂法将氧化锌纳米颗粒滴涂在自制铅笔芯电极上制成氧化锌修饰铅笔芯电极,当以过硫酸根为共反应剂时,该修饰电极在氢氧化钠溶液中具有良好的电致化学发光(ECL)行为,对其发光机理进行了考察。基于苯酚对该修饰电极的ECL具有抑制作用,建立了一种测量苯酚的新方法,当苯酚浓度为2×10~(-8)~2×10~(-6)mol/L时,发光强度与苯酚浓度的对数呈线性关系,检出限为1×10~(-8)mol/L。该方法具有灵敏度高、方法简单、快速、稳定性好等优点,将其应用于工业废水中苯酚浓度的检测,回收率为96.5%~104.5%。     

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.     

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.     

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.     

电致化学发光抑制效应测定硫脲

在自制的ECL-1型电致化学发光仪上,用电化学发光法研究了硫脲.发现硫脲对新的酰肼类试剂6-[2,4-二羟基苯基偶氮]-2,3-二氢-1,4-酞嗪二酮(DHDHD)在Na₂CO₃-NaHCO₃-KCl体系中的电化学发光有较强的抑制效应.在0.05～5mg/L范围内,硫脲浓度的对数与发光强度有良好的线性关系.0.2mg/L的硫脲,相对标准偏差为2%.并探讨了发光机理.     

基于铱纳米棒的电致化学发光生物传感器用于多巴胺检测

铱(Ⅲ)配合物差的水溶性限制了其在电致化学发光(ECL)领域的应用.该文用聚(苯乙烯-马来酸酐)(PSMA)羧基功能化三(2-苯基吡啶)铱(Ⅲ)(Ir(ppy)3)合成水溶性铱纳米棒(IrNDs).在共反应试剂三丙胺(TPrA)存在下,IrNDs表现出优良的ECL性能.借助多巴胺(DA)对Ir NDs-TPrA体系EC...     

Direct Determination of Bacterial Cell Viability Using Carbon Nanotubes Modified Screen‐printed Electrodes

For the early detection of bacterial infection, there is a need for rapid, sensitive, and label‐free assays. Thus, in this study, nanostrucured microbial electrochemical platform is designed to monitor the viability and cell growth of S. aureus. Using multi‐walled carbon nanotube modified screen‐printed electrodes (MWCNTs/SPE), the cyclic voltammetric measurements showed only one irreversible oxidation peak at 600 mV vs Ag/AgCl that accounts for the viable and metabolically active bacterial cells. The assay was optimized and the secreted metabolites, in the extracellular matrix, were directly detected. The peak current showed a positive correlation with viable cell numbers ranging from OD_{600 nm} of 0.1 to 1.1, indicating that the activity of live cells can be quantified. Consequently, responses of viable and non‐viable cells of S. aureus to the effects of antibiotic and respiratory chain inhibitors were determined. Thus, the proposed nanostructure‐based bacterial sensor provides a reasonable and reliable way for real‐time monitoring of live‐dead cell functions, and antibacterial profiling.     

Voltammetric Determination of Cocaine Using Carbon Screen Printed Electrodes Chemically Modified with Uranyl Schiff Base Films

Chemically modified screen printed electrodes (CM‐SPE) using [UO₂(4‐MeOSalen)(H₂O)] ? H₂O films were employed in the voltammetric determination of cocaine. The chemical modification was performed by dip coating electrode surfaces (carbon, gold, and platinum) with methanolic solution containing the Schiff base complex with subsequent drying step at room temperature. The optimized amount of the chemical modifier over the working electrode was found to be 2.39 µg mm^?2 (geometric area). The voltammetric measurements were carried out in 50 : 50 v/v methanol:water solution containing 0.05 mol L^?1 KCl and 0.1 mol L^?1 LiCl as a supporting electrolyte without oxygen elimination by inert gas flow. The best results were obtained with carbon electrodes. Cocaine exhibits a well defined irreversible anodic peak current (i_pa) at a potential (E_pa) of 0.85 V vs Ag/AgCl. The current is directly proportional to the drug concentration. An optimal accumulation potential (E_prec), and time (t_prec) of ?0.80 V (vs Ag/AgCl), and 120 s, respectively, were determined. The linear dependence of i_pa with square root of scan rate (υ) indicates that the mass transport at the electrode surface is controlled by diffusion. An optimized scan rate of 100 mV s^?1 was obtained for analytical purposes. A limit of detection (LOD) and limit of quantification (LOQ) in 110 and 390 µmol L^?1, respectively, with intra and inter‐day repeatability of 2.61 % and 3.77 %, respectively, were obtained. In interference studies the proposed method demonstrated high specificity for cocaine in the presence of morphine and 3,4‐methylenedioxymethanphetamine. The above results demonstrate that this method provides a fast and low cost procedure for determination of cocaine in trace levels.     

Flow Injection Chemiluminescence Determination of Isoniazid Using On-Line Electrogenerated Manganese(III) as Oxidant

A novel flow injection chemiluminescence (CL) system for the determination of isoniazid has been proposed. It is based on the direct CL reaction of isoniazid and Mn(III) in sulfuric acid medium. The unstable Mn(III) was on-line electrogenerated by constant current electrolysis. The CL emission intensity was linear with isoniazid concentration in the range 0.1–10 μg/mL; the detection limit was 3.2 × 10⁻² μg/mL. The whole process could be completed in 1 min with a relative standard deviation of less than 5%. The proposed method is suitable for automatic and continuous analysis and has been applied successfully to the analysis of isoniazid in pharmaceutical preparation.     

Flow Injection Chemiluminescence Determination of Gentamycin Using On-Line Electrogenerated Co(III) As the Oxidant

ABSTRACT

A novel flow-injection Chemiluminescence (CL) system for the determination of gentamycin is described, based on the direct chemiluminescence reaction of gentamycin and Co(III) in sulfuric acid media. The unstable strongly oxidative Co(III) was electrogenerated on-line with constant current electrolysis. The chemiluminescence intensity was linear with gentamycin concentrations of 0.01～80μg/ml, the detection limit being 0.005μg/ml. The whole process could be completed in 1 min with a relative standard deviation of less than 3.2%. The proposed method is rapid and simple and is suitable for automatic and continuous analysis. This method has been applied satisfactorily to the analysis of gentamycin in pharmaceutical preparations.     

基于一次性薄层色谱电极高选择电化学发光分析法测定Ni(II)的研究

基于一种新的电极制作方法, 研制了具有薄层色谱分离功能的一次性薄层色谱电极. 结合该电极的分离、保留分析物于电极表面一定空间区域的色谱分离能力与电极表面电化学发光信号的空间分辨能力, 实现了分析物的高效分离与原位高灵敏度电化学发光(ECL)检测, 建立了电化学发光分析方法与薄层色谱分离方法联用的新技术. 并以Ni^2＋离子为代表探讨了这一方法的可行性和分析特性. 在最佳的实验条件下, 该方法测定Ni^2＋离子的线性范围为5.0× 10^－9～5.0×10^－6 g/mL, 检出限为1.5×10^－9 g/mL, 相对标准偏差为2.8% (c＝1.0×10^－6 g/mL, n＝11).     

联吡啶钌电化学发光传感器测定海洛因

利用离子液体为粘合剂制作碳糊电极,采用高分子聚合法,合成包埋有Ru(bpy)2(dcbpy)2+的高分子聚合物,将钌聚合物掺杂于离子液体碳糊电极中,制作电化学发光传感器.结果表明,此传感器具有很好的电化学发光特性,与用石蜡油为粘合剂制作的电化学发光传感器相比,离子液体为粘合剂的电化学发光传感器检测三丙胺的检出限降低1个数量级.海洛因对电化学发光传感器的发光信号有很好的增强作用,基于此建立了高灵敏度检测海洛因的电化学发光分析法,海洛因浓度与电化学发光信号在2.0×10-9～2.0×10-5 mol/L范围内呈良好的线性关系,检出限为8×10-10 mol/L (S/N=3).将电化学发光传感器在5.0×10-9 mol/L海洛因溶液中采用线性循环电位连续扫描60圈,相对标准偏差小于2.2%.本方法用于血清中海洛因的检测,其回收率为94%～101%.     

Highly Sensitive Determination of Concanavalin A Lectin Based on Silver-Enhanced Electrogenerated Chemiluminescence of Luminol

A highly sensitive bioassay based on silver-enhanced luminol electrogenerated chemiluminescence (ECL) is reported for the determination of concanavalin A lectin. A gold electrode modified with the mixed self-assembled monolayer of thiolated mannoside and mercaptohexanol was used to selectively capture a target lectin, concanavalin A, through the specific interaction between mannoside and concanavalin A. Mannoside-functionalized gold nanoparticles were further introduced to the opposite binding sites of the tetrameric concanavalin A to form a sandwich-type complex. Silver enhancement step was performed to coat the surface of mannose-stabilized gold nanoparticles with silver. The deposited silver was dissolved in an acidic solution and further neutralized. The resulting silver ions were finally detected with luminol electrogenerated chemiluminescence, in which the silver ions greatly enhanced the chemiluminescence intensity. The present electrogenerated chemiluminescence bioassay detected concanavalin A from 0.190 to 10.0?µg/mL (r²?=?0.999) with a detection limit of 0.146?µg/mL (signal to noise ratio?=?3), which is much lower compared to previously reported methods such as microgravimetry, surface plasmon resonance, and colorimetry. Furthermore, the present bioassay showed good selectivity over possible interfering lectin proteins.     

碳量子点对基于能量转移电化学发光DNA传感体系影响的研究

实验发现在鲁米诺-结晶紫能量转移电化学发光体系中再加入碳量子点后,体系的灵敏度和重现性均提高.本实验中,探究出用能量转移电化学发光分析法区分单双链DNA的优化条件.在优化条件下,测定目标DNA的线性范围为1.0×10-11～1.0×10-7mol/L,相关系数为0.9881,检出限为4.0×10-12mol/L,并且讨论了DNA与碳量子点可能的作用方式.本法操作方便,灵敏度高.     

Hot Electron Induced Cathodic Electrochemiluminescence at Disposable Screen Printed Carbon Electrodes

Hot electron induced cathodic electrochemiluminescence (ECL) was observed at screen printed carbon electrodes (SPCEs) during pulse polarization. The thin insulating film resulted from the printing inks was found to be suitable for generating hot electrons, which can further be converted to hydrated electrons and induce the subsequent luminescence. Compared with disposable Al/Al₂O₃ electrode, SPCEs show more stable and reproducible ECL in a wider pH range without background emission. A sensitive ECL method for determination of quercetin is proposed. The detection limit is 8.0×10^?10 mol L^?1(S/N=3), which is two magnitudes lower than that of common ECL method.