金纳米粒子/碳纳米管复合修饰玻碳电极对对苯二酚氧化还原反应的电催化性能

以对苯二酚为目标化合物比较研究了金纳米粒子、碳纳米管、金纳米粒子/碳纳米管3种纳米粒子修饰电极的电催化性能,结果发现:3种纳米粒子修饰电极均对对苯二酚的电化学信号具有增强作用。电化学阻抗谱和修饰层数试验表明:金纳米粒子的增强效果来自于金纳米粒子的电催化作用,碳纳米管的增强作用来自于电催化作用与大的电极表面积,金纳米粒子/碳纳米管复合修饰电极综合利用了两种纳米粒子的特性,表现出了更为优良的电催化行为。对苯二酚在修饰电极上的电化学过程均为扩散控制过程。     

基于金纳米粒子/聚阿魏酸/多壁碳纳米管修饰电极的DNA计时库仑法生物传感器的制备

构建了基于金纳米粒子/聚阿魏酸/多壁碳纳米管(AuNPs/PFA/MWCNTs)修饰电极的DNA计时库仑法生物传感器.利用循环伏安技术在多壁碳管修饰的玻碳电极表面上聚合一层阿魏酸,在恒电位条件下,在阿魏酸表面沉积金纳米粒子,巯基DNA作为探针通过金硫键固定在金纳米粒子表面.电化学交流阻抗技术(EIS)与扫描电镜(SEM...     

间苯二酚在金纳米粒子/碳纳米管修饰电极上的电化学行为

制备了金纳米粒子/碳纳米管复合修饰玻碳电极,并用于研究间苯二酚的电化学反应过程,结果发现金纳米粒子与碳纳米管均对间苯二酚的电化学反应具有催化作用,复合修饰电极很好地利用了两种纳米粒子的电催化活性,对间苯二酚具有更强的电化学催化效果,为应用电化学技术进行间苯二酚的检测提供了可能。同时研究了碳纳米管的用量、复合膜的层数、pH值、介质和扫速等条件对间苯二酚的电化学信号的影响情况。     

纳米金/碳纳米管复合材料修饰电极催化鲁米诺电致发光体系的研究

制备了纳米金/多壁碳纳米管(MWNT)复合材料修饰电极,并将此电极应用于鲁米诺电化学发光体系.电化学发光实验表明,此复合材料修饰电极同时具备了纳米金和碳纳米管的催化性能.此外通过电极活性表面积测算、电化学交流阻抗实验等方法研究了纳米金和碳纳米管在此体系催化过程中的作用.纳米金/碳纳米管修饰电极具有良好的重现性,可以广泛应用于鲁米诺电化学发光测定体系.     

硫化银纳米球负载金纳米粒子信号放大的大肠杆菌O157:H7电化学免疫传感器

设计了一种利用碳纳米管作为基底固定材料以及硫化银纳米球负载金纳米粒子做为电化学标记信号的无酶免疫传感器,用于检测大肠杆菌O157:H7。同时引入具有信号放大功能的硫化银纳米球负载金纳米粒子作为标记物,并采用示差脉冲伏安法对金纳米粒子进行检测,其产生的电化学信号在一定范围内与大肠杆菌O157:H7的浓度呈线性关系。在最优条件下,该传感器线性范围为:1×10~3~1×10~7cfu/m L,检出限为4×10~2cfu/m L,并且具有良好的精密度和稳定性。该免疫传感器可以用于大肠杆菌O157:H7的快速检测。     

纳米硒/多壁碳纳米管复合材料的制备及其电化学性能

经混酸纯化处理的多壁碳纳米管(MWCNTs)负载纳米硒(Nano-Se0)制备纳米硒/多壁碳纳米管复合材料(Nano-Se0/MWCNTs,简称1),其结构经IR,TEM和SEM表征.以Fe(CN)4-/3-6 为探针离子,采用循环伏安法和电化学阻抗法考察了1的电化学性能.     

Pd/MWCNTs纳米复合材料的制备及其电催化性能研究

采用简便的原位合成法,将立方晶形Pd纳米粒子高效负载在多壁碳纳米管(MWCNTs)表面,制备了Pd/MWCNTs纳米复合材料。通过改变Pd(acac)2和MWCNTs的投料比,调控负载于MWCNTs表面的Pd纳米粒子的粒径及密度。运用扫描电子显微镜(SEM)、热重分析仪(TG/DTA)、X射线粉末衍射仪(XRD)等技术手段对Pd/MWCNTs纳米复合材料进行详细表征。电化学实验结果表明,Pd/MWCNTs纳米复合材料对甲醇和过氧化氢展现出良好的电催化性能。     

金纳米粒子-过氧化聚吡咯-碳纳米管复合膜修饰电极同时测定对苯二酚和邻苯二酚

将多壁碳纳米管(MWCNTs)滴涂于复合陶瓷碳电极(CCE)表面,采用电化学方法在碳纳米管表面逐层沉积过氧化聚吡咯(OPPy)和金纳米粒子(AuNPs),制得金纳米粒子-过氧化聚吡咯-多壁碳纳米管复合膜修饰电极(AuNPs-OPPy-MWCNTs/CCE).采用扫描电镜和电化学方法对修饰电极进行了表征.在0.10 mol/LPBS (pH 7.0)缓冲溶液中研究了对苯二酚(HQ)和邻苯二酚(CC)在修饰电极上的电化学行为.结果表明,修饰电极对HQ和CC的电极过程具有良好的电化学响应和区分效应.基于此建立了一阶导数伏安法同时测定HQ和CC的方法,HQ和CC的线性范围均为2.0×10-7～ 1.0×10-4 mol/L,检出限分别为6.0×10-8 mol/L和8.0×10-8 mol/L(S/N=3).模拟水样中的加标回收率分别为96.2％～99.8％ (HQ)和96.0％～100.0％,表明本方法具有良好的实用性.     

基于多壁碳纳米管负载金纳米粒子修饰的甲基对硫磷分子印迹电化学传感器的研制

本文以四氨基苯硫酚作为功能单体、甲基对硫磷(MP)作为模板分子,通过电聚合的方法在多壁碳纳米管负载金纳米粒子修饰的玻碳电极表面成功构建了MP分子印迹电化学传感器。借助循环伏安、电化学阻抗和差示脉冲等方法对传感器的电化学性能、选择性、稳定性以及重现性进行了研究。并将所建立的方法应用于黄河水中MP的加标回收检测,结果令人满意。该方法无需进行预处理,选择性好、灵敏度高、重现性好,为分析检测MP分子提供了一种非常有效的方法。     

碳纳米管负载纳米金-石墨烯量子点修饰电极电化学检测过氧化氢

采用过氧化氢刻蚀法制备石墨烯量子点(GQDs),再采用原位化学还原法制备金纳米粒子-石墨烯量子点纳米复合物(Au NPs-GQDs),最后以聚二甲基二烯丙基氯化铵(PDDA)为交联剂将上述纳米复合物组装于多壁碳纳米管表面,制得金纳米粒子-石墨烯量子点-PDDA-多壁碳纳米管复合材料(Au NPs-GQDsPDDA-MWCNTs)。通过荧光光谱法、紫外-可见吸收光谱法和透射电子显微镜对上述复合材料进行表征。采用滴涂法制得该复合材料修饰的玻碳电极,研究了过氧化氢在该电极上的电化学行为。结果表明:在石墨烯量子点、金纳米粒子和多壁碳纳米管三者的协同作用下,该电极对过氧化氢的电氧化表现出强的催化活性。在优化条件下,安培法检测H_2O_2的线性范围为2.0×10~(-8)~1.5×10~(-3)mol/L,检出限(3sb)为8.0×10~(-9)mol/L,灵敏度为61.6μA/(mmol·L~(-1))。     

Electrochemical Determination of Phenylethanolamine A Based on Nafion/MWCNTs/AuNPs Modified Carbon Electrode

Phenylethanolamine A (PEA), a β‐agonist, was found to be illegally used as a growth promoter in pigs last year, causing Chinese government's great attention. Here, a sensitive electrochemical method was developed for detecting PEA by immobilization of gold nanoparticles (AuNPs), multiwalled carbon nanotubes (MWCNTs) and Nafion on the surface of a glassy carbon electrode (GCE). The Nafion/MWCNTs/AuNPs film was characterized by scanning electronic micrographs (SEM) and electrochemical impedance spectroscopy (EIS). The electrochemical behaviors of PEA at the modified GCE were investigated in detail. The synergetic effects of AuNPs, MWCNTs and Nafion amplify the electrochemical reduction signal of PEA, and result in high sensitivity for PEA determination. Under the optimal conditions, the electrochemical sensor shows a wide linear range of 0.01 to 10 (mol/L with a detection limit of 0.005 µmol/L. Moreover, the fabricated sensor presents high selectivity and long‐term stability, which paves a new way for simple, rapid, sensitive detection of PEA.     

Sensitive and Selective Electrochemical Sensor Based on Molecularly Imprinted Polypyrrole Hybrid Nanocomposites for Tetrabromobisphenol A Detection

Abstract

A sensitive and selective electrochemical sensor based on electropolymerized molecularly imprinted polypyrrole and gold nanoparticles–multiwalled carbon nanotubes (AuNPs–MWCNTs) hybrid nanocomposites was developed for the determination of tetrabromobisphenol A (TBBPA). A glassy carbon electrode (GCE) was modified with MWCNTs, and the AuNPs–MWCNTs/GCE was prepared by an electrodeposition method in HAuCl₄ solution. The AuNPs–MWCNTs nanocomposite showed high electrocatalytic activity, good conductivity, and sufficient reactive sites for the direct electro-oxidation of TBBPA. The molecularly imprinted polymers (MIPs) as recognition elements were synthesized through in situ electro-polymerization of pyrrole as functional monomers in the presence of the TBBPA template molecules. Under the optimal conditions, the developed sensor exhibited good selectivity towards TBBPA compared with structural analogs, high sensitivity, and excellent producibility. The electrochemical responses of the sensor toward TBBPA were obtained in the linear range from 0.5?nM to 1?μM with a limit of detection equal to 0.24?nM at a signal-to-noise ratio of 3.     

Voltammetric study on pristine and nitrogen-doped multi-walled carbon nanotubes decorated with gold nanoparticles

Films consisting of pristine multi-walled carbon nanotubes (MWCNTs) and nitrogen-doped MWCNTs (N-MWCNTs) were fabricated by means of chemical vapor deposition and chemically decorated with gold nanoparticles (AuNPs). Optical microscopy and image analysis reveal that the deposited AuNPs have diameters of 50–200 nm and 100–400 nm, respectively. The AuNP-modified films of MWCNTs and of N-MWCNTs were initially investigated with respect to their response to the ferro/ferricyanide redox system. The N-MWCNTs/AuNPs exhibit lower detection limit (0.345 μM) for this redox system compared to that of MWCNTs/AuNPs (0.902 μM). This is probably due to the presence of nitrogen that appears to enhance the electrocatalytic activity of MWCNTs. The findings demonstrate that the electrochemical responses of both films are distinctly enhanced upon deposition of AuNPs on their surfaces. The detection limits of MWCNTs/AuNPs and N-MWCNTs/AuNPs systems are lower by about 43 % and 27 %, respectively, compared to films not modified with AuNPs. The electrocatalytic activity of the films towards the oxidation of ascorbic acid (AA), uric acid (UA), and dopamine (DA) was studied. The findings reveal that N-MWCNTs/AuNPs represent a powerful analytical tool that enables simultaneous analysis of AA, UA, and DA in a single experiment.

Mb/AuNPs/MWCNTs/GC电极对H2O2电催化性能的研究

采用还原法制备了AuNPs/MWCNTs复合材料,并构建了氧化还原蛋白质的固定化和生物传感界面AuNPs/MWCNTs/GC电极.以肌红蛋白(Myoglobin,Mb)为例,研究了固定化蛋白质在AuNPs/MWCNTs/GC电极上的直接电化学.结果表明,AuNPs/MWCNTs复合材料不仅能有效地促进Mb与电极表面的直接电子转移,而且能很好地保持固定化Mb的生物催化活性.Mb/AuNPs/MWCNTs/GC电极对H2O2具有良好的电催化还原性能,其线性响应范围为1～138μmol·L-1,检测限为0.32μmol·L-1(S/N=3),并具有较低的米氏常数(0.143 mmol·L-1).该电极操作简单,响应迅速,稳定性和重现性好,有望用于蛋白质的固定化及第三代生物传感器的制备.     

POMs as Active Center for Sensitively Electrochemical Detection of Bisphenol A and Acetaminophen

A new type of electrochemical sensor based on multi-walled carbon nanotubes(MWCNTs), K2H4SiW11CuO39-6H2O(SiW11Cu) and gold nanoparticles(AuNPs) was prepared for the simultaneous detection of bisphenol A and acetaminophen. Differential pulse voltammetry(DPV), cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS) were used for electrochemical characterization, and Fourier transfonn infrared spectroscopy(FTIR) was used to characterize the structure of polyoxometalates. Electrochemical experimental results show that the composite modified electrodes have good electrochemical activity as well as current response values of bisphenol A and acetaminophen when pH=7.0. At the same time, the modified electrode exhibits good stability and reproduction, and has good anti-interference ability to other substances. In practical application, the sensor obtained satisfactory results.     

Gold nanoparticles/carbon nanotubes/ionic liquid microsized paste electrode for the determination of cortisol and androsterone hormones

A novel nanocomposite electrode material constituted of gold nanoparticles (AuNPs), multi-walled carbon nanotubes (MWCNTs) and n-octylpyridinium hexafluorophosphate (OPPF₆) ionic liquid was prepared and checked for the development of electrochemical (bio)sensing devices. AuNPs/MWCNTs/OPPF₆ paste electrodes with micrometer dimensions (500 μm, i.d.) were constructed and applied to the determination of cortisol and androsterone hormones. Regarding cortisol determination, the microsized paste electrode was used to detect 1-naphtol generated upon addition of 1-naphthyl phosphate as enzyme substrate in the competitive immunoassay between alkaline phosphatase-labelled cortisol and cortisol. Squarewave voltammetry allowed determining the hormone within the 0.1- to 10-ng/mL linear range (r?=?0.990) with a detection limit of 15 pg/mL and a EC₅₀ value of 0.46?±?0.06 ng/mL cortisol. The method was applied to the determination of cortisol in urine and serum samples containing a certified cortisol content. Moreover, a microsized enzyme biosensor prepared by bulk modification of the AuNPs/MWCNTs/OPPF₆ electrode with the enzyme 3α-hydroxysteroid dehydrogenase was used for the determination of androsterone through the amperometric detection of reduced nicotinamide adenine dinucleotide. A calibration plot with a linear range between 0.1 and 120 μg/mL (r?=?0.993) and a limit of detection of 89 ng/mL were obtained. The biosensor was applied to the analysis of human serum spiked with androsterone at the 250 ng/mL concentration level.     

Electrochemical Immunosensor for Lactate Dehydrogenase Detection Through Analyte-driven Catalytic Reaction on Multi-walled Carbon Nanotubes and Gold Nanoparticle Modified Carbon Electrode

A novel electrochemical immunosensor for lactate dehydrogenase (LDH) detection was proposed based on analyte-driven catalytic reaction by attaching LDH antibodies on multi-walled carbon nanotubes (MWCNTs) and gold nanoparticles (AuNPs) modified glassy carbon electrodes (GCE). As LDH was captured by the antibodies on electrode surface, it catalyzed the formation of pyruvate and the reduced form of nicotinamide adenine dinucleotide (NADH), thus a sensitive electrochemical signal obtained from the above redox reaction was recorded by differential pulse voltammetry (DPV). Under optimum conditions, the developed immunosensor exhibits high sensitivity for LDH quantification ranging from 0.001 μg/mL to 0.5 μg/mL with a low detection limit at 0.39 ng/mL. This developed immunosensor reveals ideal accuracy and feasibility for LDH detection in Streptococcus uberis (S. uberis) induced bovine mammary epithelial cells (MECs) samples by comparison with conventional commercial kit, which shows remarkably application potential in diseases diagnosis.     

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.