芦丁在铂纳米/碳纳米管修饰电极上电化学行为研究

通过电沉积的方式在多壁碳纳米管(MWCNTs)修饰玻碳电极表面上沉积铂(pt)纳米粒子,并运用循环伏安法(CV)、示差脉冲伏安法(DPV)探讨了芦丁在铂纳米/碳纳米管/玻碳电极上的电化学行为.实验结果表明,芦丁在该修饰电极上呈现一对良好氧化还原峰,其氧化峰电流与浓度在3.2×10(-8)～1.2×10(-5)mol/L...     

新型纳米金直接修饰玻碳电极的制备及其电催化活性

在不使用交联剂的情况下,借助种子媒介纳米金属生长法将纳米金直接修饰到玻碳电极表面.试验发现纳米金粒子在电极表面覆盖率为5.4×10-10 mol·cm-2,[Fe(CN)6]3-/[Fe(CN)6]4-氧化还原电子探针的试验证明,纳米金修饰玻碳电极表面的电子传递速率是使用交联剂制备电极的四倍.与裸玻碳电极相比,抗坏血酸在该电极表面的氧化峰电位负移150 mV,峰电流提高2.2μA,同时与尿酸的氧化峰电位差达到186 mV,可用于抗坏血酸和尿酸的同时检测.     

普鲁士蓝/多壁碳纳米管修饰电极测定维生素C

利用电化学方法在多壁碳纳米管修饰的玻碳电极表面聚合一层普鲁士蓝,制备普鲁士蓝/多壁碳纳米管修饰玻碳电极,运用循环伏安法研究了维生素C(vc)在该修饰电极上的电化学行为.该修饰电极对Vc显示出快速的电化学响应和较好的电催化活性,在pH为4.0的磷酸盐溶液中,Ve浓度与其氧化峰电流在8.0×10-4～1.0×10-2 mol/L范围内呈现良好的线性关系,相关系数为0.9993,检测限为6.4×10-5mol/L.该电极具有较好的稳定性和重现性.     

纳米复合物修饰电极的电化学传感器检测芦丁

研制了纳米复合物修饰电极,碳纳米管与表面含有大量氨基的壳聚糖在玻碳电极表面首先形成碳纳米管/壳聚糖膜,通过膜表面丰富的氨基与纳米Au的强静电吸附,在玻碳电极表面获得均匀致密的纳米金修饰层.这种基于纳米复合材料制备的新型电化学传感器对芦丁具有很好的响应,可以快速地实现电极与芦丁之间的直接电子转移,有良好的稳定性.芦丁的测定线性范围为4.00×10-7～1.77×10-5 mol/L,最低检测限为1.29×10-7 mol/L.由于抗坏血酸在该修饰电极上的氧化电位出现显著负移,因此可避免抗坏血酸对芦丁测定的干扰.该方法可以不经预分离直接检测药物中的芦丁含量.     

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。     

基于Nafion-氧化石墨烯复合物/硫堇/纳米金构建过氧化氢传感器的研究

利用Nafion(全氟聚苯乙烯磺酸溶液)-氧化石墨烯复合物、硫堇和纳米金构建了H2O2酶传感器。首先将氧化石墨烯分散在体积分数0.2%Nafion溶液中制得Nafion-氧化石墨烯的复合物,并将其固定在玻碳电极表面,通过静电吸附将带正电荷的硫堇吸附到Nafion-氧化石墨烯复合膜修饰的玻碳电极表面,再利用静电吸附将纳米金修饰于电极上,通过纳米金来固定辣根过氧化物酶从而制得H2O2传感器。用循环伏安法和计时电流法考察该修饰电极的电化学特性。H2O2浓度为5.5×10-6~1.0×10-3mol/L时,酶电极的响应电流值与H2O2的浓度呈良好的线性关系,检出限为1.80×10-6mol/L。     

纳米铂直接修饰玻碳电极的制备及在半胱氨酸中的电化学行为

采用一步化学原位还原法将球形纳米铂颗粒直接修饰在玻碳电极上,用SEM、EDS和电化学方法对该电极进行表征并与铂片电极、裸玻碳电极进行了对比。结果表明,纳米铂修饰电极的峰电流与扫描速度呈线性关系,纳米铂在电极表面覆盖率为1.28×10-7mol/cm2。循环伏安法研究结果表明纳米铂修饰电极对半胱氨酸的催化氧化作用和铂片电极相比提高了数倍,且峰电位负移了0.3V。在纳米铂修饰的玻碳电极上,半胱氨酸的浓度在1.0×10-7mol/L到1.0×10-5mol/L范围内和催化电流呈线性关系。     

基于多壁碳纳米管/壳聚糖多层膜修饰玻碳电极邻苯二酚的测定

改进了碳纳米管在壳聚糖溶液中的分散方法,制备了多壁碳纳米管/壳聚糖多层膜修饰玻碳电极,对比了不同修饰层数膜电极的循环伏安和电化学阻抗行为,5层多壁碳纳米管/壳聚糖膜修饰玻碳电极的电化学性能优良.在最优实验条件下,该修饰玻碳电极对邻苯二酚(CAT)有灵敏的响应,CAT浓度在3.99×10-6～9.09×10-4mol/L范围内与氧化峰电流呈良好的线性关系,检出限为2.39×10-6mol/L(S/N=3).该修饰玻碳电极性能稳定,测定4×10-5mol/LCAT溶液,RSD(n=10)为2.1%;15周后,该电极的响应值仅降低1.9%.     

一种基于乙炔黑/壳聚糖膜修饰电极的对氨基酚传感研究

制备了一种乙炔黑/壳聚糖薄膜修饰的玻碳电极,用循环伏安法详细研究了对氨基酚在该修饰电极上的电化学行为.结果表明: 对氨基酚在此膜修饰电极上呈现出一对可逆的氧化还原峰.相对于裸玻碳电极,该氧化还原峰的峰电流明显提高,峰电位差减小,可逆性变好,表明乙炔黑/壳聚糖薄膜电极对对氨基酚的电化学氧化具有良好的催化作用.对氨基酚的氧化峰电流与其浓度在1.0×10-7～2.0×10-6 mol/L和2 0×10-6～5.0×10-4 mol/L范围内均呈良好的线性关系; 检出限为5.0×10-8 mol/L(S/N=3).应用此修饰电极测定实际水样,结果较满意.     

金纳米颗粒在玻碳电极表面的固载及其对抗坏血酸的电催化氧化

采用电化学方法先在玻碳电极(GCE)表面共价键合一末端带有巯基的2-氨基乙硫醇(AET)单层,通过硫-金相互作用将金纳米颗粒(GNP)固载在玻碳电极表面,制备了GNP修饰的GNP-AET/GCE电极.采用X射线光电子能谱和循环伏安法对固载纳米金的玻碳电极的结构和性能进行表征.研究发现:GNP-AET/GCE电极不仅对抗坏血酸具有良好的催化性能,使其氧化过电位由玻碳电极上的0.53V负移到0.33V,氧化峰电流明显增加,而且能将多巴胺和抗坏血酸在玻碳电极上重叠的氧化波分成两个独立的氧化峰,峰间电位差为0.29V,提出了用差分脉冲伏安法在多巴胺共存在测定抗坏血酸的选择性方法.峰电流与抗坏血酸浓度在8.5×10-6～1.0×10-4 mol·L-1之间呈线性关系,其检出限为4.7×10-6 mol·L-1.     

Electrochemiluminescent detection of the hybridization of oligonucleotides using an electrode modified with nanocomposite of carbon nanotubes and gold nanoparticles

We report on an electrochemiluminescent (ECL) sensing technique for the detection of the hybridization between oligonucleotides. A glassy carbon electrode was first functionalized with a composite prepared from gold nanoparticles and carbon nanotubes, and a sensor was then constructed by immobilizing the probing oligonucleotide. The ECL of luminol acts as the sensing signal. It is quenched, to a different degree, by the hybridized double strands of the oligonucleotide depending on the match status. The slope of the ECL response as a function of the status of hybridization drops with increasingly matched hybridization. The response is attributed to the interaction between luminol and the strands of oligomers, and also related to the reduction of reactive oxygen species.

Used gold nano-particles as an on/off switch for response of a potentiometric sensor to Al(III) or Cu(II) metal ions

The potentiometric response of a carbon paste electrode modified with silica sol-gel and mercaptosuccinic acid (MSA) in the presence and absence of gold nano-particles was studied. The results showed that the electrode with gold nano-particles was responded to Al(3+) ions as a hard metal ion. On the other hand, the electrode without gold nano-particles was responded to copper ions as a soft metal ion. The electrodes without and with gold nano-particles exhibits a Nernstian slope of 29.1 and 19.2 mV decade(-1) for copper and aluminum ions over a wide concentration range of 4.3×10(-7)-1.0×10(-2) and 4.5×10(-7)-1.6×10(-3) mol L(-1), respectively. The detection limits of electrodes were 4.0×10(-7) and 1.6×10(-7) mol L(-1) for copper and aluminum ions, respectively.     

氧化锌纳米簇-金纳米颗粒-壳聚糖复合膜修饰电极用于示差脉冲伏安法测定吗啡

将制备的氧化锌纳米簇和金纳米颗粒分散在壳聚糖中并滴涂在玻碳电极表面,制备了氧化锌纳米簇-金纳米颗粒-壳聚糖复合膜修饰电极(Au-ZnO-CHIT/GCE)。采用循环伏安法研究了吗啡在修饰电极上的电化学行为。结果表明:吗啡在该修饰电极上出现了一个氧化峰,提出了用示差脉冲伏安法测定吗啡的方法。吗啡浓度在5.3×10-6~6.5×10-4mol.L-1范围内与氧化峰电流呈线性关系,检出限(3S/N)为1.8×10-6mol.L-1。修饰电极用于尿液中吗啡的测定,回收率在80.0%~99.6%之间。     

Electrochemical determination of nitrite using a gold nanoparticles-modified glassy carbon electrode prepared by the seed-mediated growth technique.

Seed-mediated growth of gold nanoparticles on glassy carbon (GC) surfaces was developed. The field emission scanning electron microscopy (FE-SEM) and electrochemical characterization confirmed the effective attachment of gold nanoparticles on GC surface with such a wet-chemical method. The as-prepared gold nanoparticles attached glassy carbon electrode (Au/GCE) presented excellent catalytic ability toward the oxidation of nitrite. Compared with bare GCE and planar gold electrode, the Au/GCE obviously decreased the overpotential of nitrite oxidation and improved the peak current. The catalytic current was found to be linearly proportional to the nitrite concentration in the range of 1 x 10(-5) - 5 x 10(-3) M, with a detection limit of 2.4 x 10(-6) M. The Au/GCE was successfully applied to the electrochemical determination of nitrite in a real wastewater sample, showing excellent stability and anti-interference ability.     

Au/GCE电极对水中15种苯酚衍生物的测定

研究了15种不同取代基苯酚衍生物在纳米金/玻碳 (Au/GCE) 电极上的电化学响应. 测试表明：该电极对15种苯酚衍生物的电化学反应各呈现出不同程度的电催化作用;与GCE和平面金电极相比,苯酚衍生物的氧化峰电流均有所增加,氧化电位受待测物反应活性影响较大;水杨酸在Au/GCE电极上响应迅速,电流灵敏度是GCE电极的1.8倍;该电极可用于多种苯酚衍生物的痕量测定.     

Catalytic Effect on Silver Electrodeposition of Gold Deposited on Carbon Electrodes

A new methodology, based on silver electrocatalytic deposition and designed to quantify gold deposited onto carbon paste electrode (CPE) and glassy carbon electrode (GCE), has been developed in this work. Silver (prepared in 1.0 M NH₃) electrodeposition at ?0.13 V occurs only when gold is previously deposited at an adequate potential on the electrode surface for a fixed period of time. When a CPE is used as working electrode, an adequate oxidation of gold is necessary. This oxidation is carried out in both 0.1 M NaOH and 0.1 M H₂SO₄ at oxidation potentials. When a GCE is used as working electrode, the oxidation steps are not necessary. Moreover, a cleaning step in KCN, which removes gold from electrode surface, is included. To obtain reproducibility in the analytical signal, the surface of the electrodes must be suitably pretreated; this electrodic pretreatment depends on the kind of electrode used as working electrode. Low detection limits (5.0×10^?10 M) for short gold deposition times (10 min for CPE and 5 min for GCE) were achieved with this novel methodology. Finally, sodium aurothiomalate can be quantified using silver electrocatalytic deposition and GCE as working electrode. Good linear relationship between silver anodic stripping peak and aurothiomalate concentration was found from 5.0×10^?10 M to 1.0×10^?8 M.     

聚对氨基苯磺酸修饰玻碳电极不可逆双安培法测定酪氨酸

在玻碳电极上成功地制备了聚对氨基苯磺酸修饰电极(P-p-ABSA/GCE),研究了酪氨酸在该修饰电极上的电化学行为.将此修饰电极用于流动注射不可逆双安培体系的构建,建立了流动注射双安培法直接测定酪氨酸的方法.在0 V外加电压下,在0.005 mol/L硫酸载液中,酪氨酸的氧化峰峰电流与其浓度在2.0×10-6 ～2.0×10-4 mol/L范围内呈良好的线性关系,方法的检出限(S/N=3)为1.0×10-7 mol/L.连续测定1.00×10-5 mol/L的酪氨酸标准溶液,电流值的相对标准偏差(RSD)为1.48%(n=20).该方法具有较高的选择性和灵敏度,应用于测定复方氨基酸注射液中酪氨酸的含量的测定,结果比较满意.     

Voltammetric study of sodium hypochlorite using dendrimer-stabilized gold nanoparticles

Electrochemical activity of dendrimer-stabilized gold nanoparticles on a glassy carbon electrode (GCE) was studied by means of cyclic voltammetry of sodium hypochlorite. Dendrimer-stabilized gold nanoparticles were deposited onto a glassy carbon surface by electrophoresis and the deposition was observed by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Both anodic and cathodic peak currents were found to increase after the deposition of dendrimer-stabilized gold nanoparticles. In the case of dendrimers deposited onto the GCE surface, the magnitude of the current was smaller than for dendrimer-stabilized-gold-nanoparticle-modified GCE. This indicates the enhancement in the rate of electrolysis due to gold nanoparticles.     

Sensitive determination of hydrazine using poly(phenolphthalein), Au nanoparticles and multiwalled carbon nanotubes modified glassy carbon electrode

This study reports a detailed analysis of an electrode material containing poly(phenolphthalein), carbon nanotubes and gold nanoparticles which shows superior catalytic effect towards to hydrazine oxidation in Britton–Robinson buffer (pH 10.0). Glassy carbon electrode was modified by electropolymerization of phenolphthalein (PP) monomer (poly(PP)/GCE) and the multiwalled carbon nanotubes (MWCNTs) was dropped on the surface. This modified surface was electrodeposited with gold nanoparticles (AuNPs/CNT/poly(PP)/GCE). The fabricated electrode was analysed the determination of hydrazine using cyclic voltammetry, linear sweep voltammetry and amperometry. The peak potential of hydrazine oxidation on bare GCE, poly(PP)/GCE, CNT/GCE, CNT/poly(PP)/GCE, and AuNPs/CNT/poly(PP)/GCE were observed at 596 mV, 342 mV, 320 mV, 313 mV, and 27 mV, respectively. A shift in the overpotential to more negative direction and an enhancement in the peak current indicated that the AuNPs/CNT/poly(PP)/GC electrode presented an efficient electrocatalytic activity toward oxidation of hydrazine. Modified electrodes were characterized with High-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). Amperometric current responses in the low hydrazine concentration range of 0.25–13 µM at the AuNPs/CNT/poly(PP)/GCE. The limit of detection (LOD) value was obtained to be 0.083 µM. A modified electrode was applied to naturel samples for hydrazine determination.     

Au Nanowires-MWCNTs修饰电极对葡萄糖的催化氧化

通过油胺(Oleylamine)还原法制备了金纳米线(Au nanowires),将其与酸化处理的多壁碳纳米管(MWCNTs)通过层层组装制备了Au nanowires-MWCNTs复合结构修饰的玻碳电极(Au nanowires-MWCNTs/GCE).电化学研究结果表明,与单纯Au nanowires或MWCNTs修饰电极相比,Au nanowires-MWCNTs/GCE对葡萄糖表现出更优良的电催化性能.以Au nanowires-MWCNTs/GCE为阳极,电沉积Pt膜电极(Pt/GCE)为阴极,构建了葡萄糖/O2燃料电池.测试结果表明,构建的燃料电池的开路电位(OCP)为0.57 V,在0.44 V下最大功率密度(Pmax)为0.28 m W/cm2.