聚多巴胺-纳米金修饰玻碳电极检测芦丁

采用一锅法制备聚多巴胺-纳米金修饰玻碳电极(PDA-AuNPs/GCE),用扫描电子显微镜(SEM)对修饰电极进行表面形貌分析,并研究芦丁在该修饰电极上的电化学行为。实验表明,PDA-AuNPs/GCE对芦丁有较好的电催化氧化性能,芦丁的氧化峰电流与其浓度在1.0×10-6～1.0×10-4mol·L-1范围内成线性关系,检测下限为2.3×10-7mol·L-1(S/N=3)。该修饰电极可用于复方芦丁片中芦丁含量的检测,效果良好。     

纳米金修饰玻碳电极在抗坏血酸共存下选择性测定多巴胺

利用电沉积的方式制备了纳米金 ( Nano- gold,NG)修饰玻碳电极 ( GCE)。该电极对多巴胺 ( DA)和抗坏血酸 ( AA)均有催化作用 ,且多巴胺在纳米金修饰玻碳电极上有较强的吸附作用。同时研究了磷酸缓冲溶液的 p H值和离子强度对 DA的电化学行为的影响。纳米金修饰玻碳电极在 DA和 AA的混合溶液中的循环伏安图上可观察到两个明显分开的氧化峰 ,峰电位差达到 1 5 0 m V。据此 ,提出了两种利用该电极在抗坏血酸共存下选择性测定多巴胺的方法 ,线性范围分别为 3.0× 1 0 - 6 ～1 .0× 1 0 - 4mol/ L和 1 .2 5× 1 0 - 6 ～ 1 .0× 1 0 - 4mol/ L。     

己硫醇二茂铁复合金纳米粒子修饰电极对多巴胺的催化性能研究

将自行合成的己硫醇二茂铁自组装于金纳米粒子表面,获得己硫醇二茂铁复合金纳米粒子（Au@S（CH2）6Fc）。采用滴涂法将制备的复合纳米粒子固定于玻碳电极表面,制备Au@S（CH2）6Fc修饰电极,采用循环伏安法对修饰电极的电化学性能进行考察。将制备的修饰电极用于对神经递质多巴胺（DA）的催化氧化性能研究。结果表明,该修饰电极对DA具有显著的催化氧化作用,线性范围为1.0×10^-6-2.6×10^-3mol/L,检出限为3.0×10^-7mol/L。     

纳米金修饰的碳纤维超微电极在高浓度抗坏血酸体系中选择性测定多巴胺

将柠檬酸三钠与硼氢化钠还原氯金酸制备纳米金颗粒,采用一步恒电位沉积的方法在碳纤维超微电极上沉积纳米金颗粒,并对电极进行电化学表征。分别对100μmol/L DA、1mmol/L AA在该电极上修饰前后的电化学行为进行了研究,结果表明在浓度为1 mmol/L抗坏血酸共存下,DA的浓度(0. 1～10μmol/L)与氧化峰电流成正比,线性回归方程为Ip(μA)=200 c(μmol/L)+2×10~(-4),相关系数R~2=0. 9979,线性范围0. 1～10μmol/L,检出限为1. 28×10~(-2)μmol/L (S/N=3)。方法可用于较高浓度抗坏血酸共存下对多巴胺的选择性测定。     

金纳米电极对多巴胺和5-羟色胺的电化学富集和拉曼光谱检测

对小分子神经递质多巴胺(Dopamine, DA)和5-羟色胺(5-Hydroxytryptamine, 5-HT)的同时分析和检测是生命科学领域中的研究热点。单一的电化学检测手段难以有效地识别分析物,因此,多模量的同时分析尤为重要。本研究在碳纳米电极(Carbon-nanoelectrode nanopipette, CNE-NP)的基础上,通过电化学反应在其尖端沉积金,构建了一种具有电化学特性和拉曼活性的双功能金纳米电极(Gold-nanoelectrode nanopipette, GNE-NP)。经过交流介电泳(Dielectrophoresis, DEP)富集后,可用于对低浓度的DA和5-HT的检测分析。研究结果表明,此电极实现了两者的电化学响应的增强和区分。此外,引入的银纳米颗粒(AgNPs)作为拉曼增强因子和捕获分析物的纳米颗粒,同样地经过DEP富集方法,使分析物的拉曼信号增强了2个数量级,且能对共混物进行特征峰的区分。将此电极应用于血浆样品分析,可得到富集增强的电化学响应,但电化学响应会受到富集次数的限制。     

基于铜离子修饰金纳米簇“关-开”型荧光探针检测多巴胺

以11-巯基十一烷酸(11-MUA)为还原剂和保护剂,通过一步水热法合成了具有强烈荧光的水溶性金纳米簇(AuNCs),基于Cu~(2+)修饰的AuNCs@11-MUA构建了"关-开"型荧光探针用于多巴胺(DA)的选择性、高灵敏检测.向AuNCs@11-MUA溶液中加入Cu~(2+)离子后,AuNCs@11-MUA的荧光发生猝灭,体系的荧光信号处于"关闭"状态.在DA存在下,由于DA与Cu~(2+)具有更强的结合力,形成比Cu~(2+)/AuNCs@11-MUA复合体更稳定的络合物,可将Cu~(2+)从AuNCs@11-MUA表面移除下来,从而使其荧光得以恢复,体系的荧光信号呈"打开"状态.AuNCs@11-MUA探针的荧光恢复程度与DA的浓度在2.0×10~(-7)~5.0×10~(-5)mol/L范围呈良好的线性关系,检出限为8.0×10~(-8)mol/L(S/N=3).将该探针应用于人血清和尿液中DA的检测,回收率为93.2%~97.3%,相对标准偏差RSD4.08%,表明该方法可应用于人体内多巴胺的检测.     

纳米金/三聚氰胺修饰电极检测亚硝酸盐

采用电聚合方法制备三聚氰胺(MA)膜修饰玻碳电极(GCE),然后采用原位恒电位沉积法制备金纳米颗粒(Au),并将其修饰于膜电极表面,制得纳米金/三聚氰胺修饰玻碳电极(Au/MA/GCE)。用扫描电子显微镜(SEM)对修饰电极进行表面形貌和元素成分分析。用循环伏安法研究亚硝酸根(NO2-)在该修饰电极上的电化学行为发现,NO2-在0.85 V出现一灵敏的氧化峰。在优化的实验条件下,NO2-在1.0×10-5～1.0×10-3mol/L浓度范围内与其氧化峰电流成线性关系,检测下限为8.9×10-7mol/L。将修饰电极用于实际样品中NO2-的检测,效果良好。     

金纳米粒子-石墨烯修饰玻碳电极的制备及对多巴胺、抗坏血酸和尿酸的同时检测

采用三步法制备了金纳米粒子-石墨烯层层组装的复合材料,并将其修饰在玻碳电极上,制备成一种新型的同时检测抗坏血酸(AA)、多巴胺(DA)和尿酸(UA)的电化学传感器。采用扫描电子显微镜(SEM)对复合材料进行了表征,并研究了传感器对AA、DA、UA电催化性能。结果表明:该传感器对AA、DA和UA的氧化具有很好的催化和分离效果,可实现AA、DA和UA的同时测定。在三者共存体系中,AA-DA、DA-UA、AA-UA的氧化峰电位差分别为152mV、161mV和313mV。线性范围分别为1.996×10-5~5.580×10-3、1.996×10-6~5.478×10-3和1.000×10-6~1.000×10-3 mol/L,检出限分别为1.200×10-5、1.030×10-7和4.100×10-7 mol/L。该修饰电极选择性好、稳定性高,有望用于实际样品中AA、DA和UA的同时检测。     

纳米碳管电极的制备与电化学检测性能研究

纳米碳管由于其独特的物理和化学性能及广阔的应用前景而备受关注,其相关研究涉及到众多领域[1￣3]。在电化学分析领域,与其它碳电极材料相比,纳米碳管电极具有较大的电极表面积和较高的电子传递速率,其使用能增大响应电流、降低检出限,是目前电化学分析电极中一个十分引人注目     

A Simple Method for Fabrication of Gold Nanoelectrodes

A facile method has been developed for the fabrication of Au nanoelecrodes (Au NEs).The tip of Au NEs can be controlled within the range from dozens to hundreds of nanometer.     

A Facile Fabrication of Poly-ethionine Film on Glassy Carbon Electrode for Simultaneous and Sensitive Detection of Dopamine and Paracetamol

An electrochemical sensor based on poly-ethionine (Poly-ET) film modified glassy carbon electrode was developed for sensitive and simultaneous sensing of dopamine (DA) and paracetamol (PA). The electropolymerization of ethionine monomer was carried out to modify the electrode. The modified electrode was characterized by using scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The Poly-ET/GCE exhibited excellent electrocatalysis towards the sensing of DA and PA. Poly-ET/GCE showed a linear increase of current response with increase concentration of DA and PA ranging from 0.1 μM–60 μM and 0.1 μM–180 μM, respectively. The LODs were found to be 7 nM and 18 nM (S/N=3) for DA and PA, respectively. This electrochemical sensor was successfully utilized for the detection of DA and PA in pharmaceutical samples.     

Diamond Nanoelectrode Arrays for the Detection of Surface Sensitive Adsorption

Nanocrystalline diamond nanoelectrode arrays (NEAs) have been applied to investigate surface‐sensitive adsorption phenomena at the diamond–liquid interface. The adsorption of neutral methyl viologen (MV⁰) was used as a model system. The adsorption of MV⁰ was examined on hydrogen‐ and oxygen‐terminated surfaces. On the hydrogenated nanoelectrode surface, a sharp anodic stripping peak was observed upon oxidation of MV⁰, revealing strong adsorption of MV⁰. In contrast, a sigmoidal voltammogram was recorded with an oxygenated electrode surface, indicating there was no MV⁰ adsorption. The changes in the shapes of these voltammograms are due to the drastic changes that occur in the diffusion profiles during the transition. The diffusion profile changes from hemispherical diffusion on oxygen‐terminated surfaces to thin‐layer electrochemistry upon adsorption on hydrogen‐terminated surfaces. Different types and concentrations of buffer solutions were then used to vary the interaction of MV⁰ with diamond NEAs. The results suggest that the adsorption of MV⁰ on hydrogen‐terminated diamond NEAs is controlled by hydrophobic interactions. Therefore, diamond NEAs are ideal for the study of adsorption phenomena at the liquid–solid interface with voltammetry.     

非电活性分子的活体电化学分析进展

发展非电活性分子的活体电化学分析方法,对于解析这些物质在生理过程和病理过程中的作用具有重要研究意义. 本综述从三种分析策略出发,简要介绍了最近活体电化学传感器的研究进展：1）设计和筛选高选择性配体,通过将特异性的化学反应转换成电化学信号,发展了新型的非电活性分子的活体分析;2）利用微型孔道里的整流效应,结合特异性配体,建立了非电活性分子的新型分析平台;3）结合微电极阵列技术及同时分析多种输出信号的新型分析模式,实现活体中的多种非电活性物质的同时分析.     

Electrochemical Formation of Nanostructured Gold Surfaces on Glassy Carbon for the Determination of Dopamine

Nanostructured gold surfaces were prepared by potentiostatic, potentiodynamic or galvanostatic Au electrodeposition on glassy carbon electrodes. The nanostructured gold electrodes (nsAu/GC) were used for the determination of dopamine (DA) in aqueous media. A directly proportional relationship was found between the peak current for DA (obtained by square wave voltammetry, SWV) and its concentration for all cases. However, the best performance for DA determination was attained with potentiodynamically electrodeposited surfaces. The SWV peak current was linearly dependent on DA concentration up to 10 μM, with a detection limit (3σ) of 0.57 μM, and a correlation coefficient (r) of 0.9966. A study on the effect of common interfering species such as ascorbic acid (AA) and uric acid (UA) on DA determination was also carried out. The use of a nanostructured surface gives rise to peaks for AA and UA that appear at 0.15–0.20 V above the peak potential for DA. The detection limit obtained for dopamine is below 1 μM in the presence of 0.1 mM AA and 0.1 mM UA. Thus, nanostructuring of glassy carbon surfaces with gold conveniently and easily improves the detection of DA in the presence of their principal interfering species.     

Gold 3D Brush Nanoelectrode Ensembles with Enlarged Active Area for the Direct Voltammetry of Daunorubicin

3D gold brush nanoelectrode ensembles (BNEEs) consisted of gold nanowires 100 nm in diameter and 300 nm in length were fabricated by combining the technologies of template synthesis and controlled chemical etching of the membrane. The structure and morphology of the BNEEs was imaged by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The real active areas of BNEEs were found to be different when characterized by different redox species. The direct redox of daunorubicin (DNR) at the gold BNEEs exhibited absorption‐controlled characteristics and high current activity. BNEEs are reliable and effective in DNR detection.     

Facile Synthesis of Graphene/Cobalt Oxide Nanohexagons for the Selective Detection of Dopamine

This work presents a simple green approach for the chemical synthesis of cobalt oxide nano hexagons (Co₃O₄ NHs) with an average size of 160±40 nm incorporated graphene nanosheets (GR). The techniques used to confirm the formation of GR−Co₃O₄ NHs are transmission electron microscopy (TEM), energy‐dispersive X‐ray spectroscopy (EDX), and X‐ray diffraction spectroscopy (XRD). The dopamine (DA) sensor was fabricated by drop casting GR−Co₃O₄ NHs on the pre‐cleaned glassy carbon electrode (GCE). GR−Co₃O₄ modified GCE displayed a sensitive and selective electrochemical determination of DA compared to only GR and Co₃O₄ NHs modified GCE. Our fabricated sensor showed a wide linear range from 0.2 to 3443 μM with low limit of detection (84 nM) towards the determination of DA. The sensitivity of our fabricated sensor was calculated to be 108 μA mM⁻¹ cm⁻². As well, a significant storage stability, repeatability and reproducibility were attained by GR−Co₃O₄ NHs modified GCE. Human urine samples were targeted for the demonstration of practicality of our sensor.     

邻氨基硫酚自组装膜修饰电极测定多巴胺

邻氨基硫酚自组装膜修饰电极测定多巴胺;多巴胺;邻氨基硫酚;自组装膜;金电极;方波伏安法     

金纳米棒非聚集比色法测定多巴胺

基于在金纳米棒(AuNRs)-Ag⁺-多巴胺(DA)体系中,DA快速将Ag⁺还原为Ag,Ag包裹在AuNRs表面形成核壳状纳米棒(Au@AgNRs),改变了AuNRs周围的电介质环境,导致其纵横比减小、纵向等离子体共振吸收波长带(LPAB)蓝移,同时伴随着溶液的颜色发生显著的变化, 藉此开发了一种快速测定DA的比色法. 方法已成功应用于血清中DA的测定,其结果与荧光法相吻合. 此外,探讨了比色法测定DA的机理.