共查询到20条相似文献,搜索用时 0 毫秒
1.
Edith Chow Jan Herrmann Christopher S. Barton Burkhard Raguse Lech Wieczorek 《Analytica chimica acta》2009,632(1):135-202
The influence of film morphology on the performance of inkjet-printed gold nanoparticle chemiresistors has been investigated. Nanoparticles deposited from a single-solvent system resulted in a “coffee ring”-like structure with most of the materials deposited at the edge. It was shown that the uniformity of the film could be improved if the nanoparticles were deposited from a mixture of solvents comprising N-methyl-2-pyrrolidone and water. Electrical conductivity measurements showed that both “coffee ring” and “flat” films were qualitatively similar suggesting that the films have similar nanoscale structures. To form the functional chemiresistor device, the 4-(dimethylamino)pyridine coating on the nanoparticle was exchanged with 1-hexanethiol to provide a hydrophobic sensing layer. The performance of 1-hexanethiol coated gold nanoparticle chemiresistors to small organic molecules, toluene, dichloromethane and ethanol dissolved in 1 M KCl in regard to changes in impedance and response times was unaffected by the film morphology. For larger hydrocarbons such as octane, the rate of uptake of the analyte into the film was significantly faster when the flatter nanoparticle film was used as opposed to the “coffee ring” film which has a thicker edge. Furthermore, the presence of potassium and chloride ions in the solution media does not significantly affect the impedance of the nanoparticle film at 1 Hz (<2% variation in film impedance over more than four orders of magnitude change in ionic strength). However, the ionic strength of the media affected the partitioning of the analyte into the hydrophobic nanoparticle film. The response of the sensor was found to increase with an increased salt concentration due to a salting-out of the analyte from the solution. 相似文献
2.
This study developed a facile technique for site‐specific synthesis of nanometer‐thick polyaniline (PANI) film for fabrication of field‐effect transistor/chemiresistor sensors. The nanothin film had a thickness of 9–20 nm and was of carpet‐like morphology offering a highly accessible surface geometry that enhanced gas adsorption and promoted surface reaction/interaction. When applied for sensing of ammonia (NH3) and nitrogen dioxide (NO2), the performance of the nanothin film device was comparable to that of a 1‐dimensional (1‐D) nanostructure, with a great advantage in ease of processing. Sensing mechanism study indicated electrostatic gating as the dominating mode of sensing. 相似文献
3.
Anna M. Nowicka Agata Kowalczyk Mikolaj Donten Dónal Leech Maria Hepel Zbigniew Stojek 《Electroanalysis》2010,22(20):2323-2329
This paper presents a way of modification of crystalline gold surface with a high quality layer of gold nanoparticles (Au NPs) via self‐assembled dithiol. The application of additional Au NPs monolayer prepared at various temperatures was tested with three types of biosensors previously described in the literature. The examined DNA biosensors differed by the detection method and the way of the immobilization of DNA probe at the modified gold electrode surface. For the immobilization of DNA probe in the sensing layer either the formation of SAM or the affinity binding (biotin – sterptavidin) or covalent attachment were used. The necessary condition of successful preparation of a perfect such monolayer is the preparation temperature of 4 °C. The preparation of Au NPs layers at higher than 4 °C temperatures leads to poor repeatability and unsatisfactory precision of the measurements. The application of the perfect Au monolayer lowers the detection limit (circa by 10 to 100 times) for all tested DNA biosensors. 相似文献
4.
5.
钯纳米粒子在电极表面的制备及其对氧的催化还原 总被引:3,自引:0,他引:3
纳米微粒的体积效应使其成为表面纳米工程及功能化纳米结构材料制备的理想研究对象 [1~ 3] .纳米粒子具有独特的电子、催化及光学特性[4 ] ,近年来关于纳米粒子的制备及其在材料科学领域中的应用受到研究者的极大关注 .而贵金属纳米粒子由于其在催化领域中的广泛应用而成为最重要的研究对象之一[5,6 ] .电催化氧还原是一直为化学家瞩目的研究领域[7~ 9] .研究主要目的之一是寻找合适的氧电极反应催化剂 ,并使之能够应用于燃料电池中 .其中催化氧电极材料研究得最多的是贵金属 Pt[10 ,11] .贵金属 Pd对氧催化还原的研究工作很少 .我们首次… 相似文献
6.
7.
Inmaculada García‐Pineda Manuel Mayén José Miguel Rodríguez‐Mellado Rafael Rodríguez‐Amaro 《Electroanalysis》2013,25(8):1981-1987
We herein report on the electrocatalytic activity towards the oxidation of NADH of a PVC/TTF‐TCNQ composite electrode modified with gold nanoparticles. This electrocatalytic property allows proposing this system as a new alternative for amperometric determination of NADH, without need to add another mediator. The sensor shows a linear response to NADH over a concentration range from 5.0×10?6 M up to 5.0×10?4 M, with a sensitivity of 11.22±0.5 mA M?1 and a detection limit (S/N=3) of 4.0×10?6 M for measurements in batch and similar data in FIA. 相似文献
8.
9.
石墨烯-壳聚糖/金纳米粒子修饰电极同时测定亚硫酸根和亚硝酸根 总被引:1,自引:0,他引:1
采用滴涂法得到了石墨烯(GR)-壳聚糖(CS)修饰的玻碳电极(GCE),再采用电沉积的方法将HAuCl4直接还原成金纳米粒子,沉积在GR-CS表面,制得了GR-CS/AuNPs GCE修饰电极。采用透射电子显微镜(TEM)分别对制备的GR和构建的修饰电极GR-CS/AuNPs GCE进行了形貌表征。用循环伏安法研究了SO32-和NO2-在GR-CS/AuNPs GCE上的电化学行为。结果表明,此修饰电极对SO32-和NO2-均有较好的电催化活性作用,并且能实现对两种物质的同时测定,SO32-和NO2-在该修饰电极上的线性范围分别为5~410μmol/L和1~380μmol/L,检出限(S/N=3)分别为1.0和0.25μmol/L。GR-CS/AuNPs GCE具有很好的稳定性、重现性和灵敏度。此电极用于实际水样的SO32-和NO2-的含量测定,回收率为97.2%~102.6%,结果令人满意。 相似文献
10.
Amplified Electrochemical DNA Sensor Based on Polyaniline Film and Gold Nanoparticles 总被引:1,自引:0,他引:1
In this work, an electrochemical DNA biosensor, based on a dual signal amplified strategy by employing a polyaniline film and gold nanoparticles as a sensor platform and enzyme‐linked as a label, for sensitive detection is presented. Firstly, polyaniline film and gold nanoparticles were progressively grown on graphite screen‐printed electrode surface via electropolymerization and electrochemical deposition, respectively. The sensor was characterized by scanning electron microscopy (SEM), cyclic voltammetry and impedance measurements. The polyaniline‐gold nanocomposite modified electrodes were firstly modified with a mixed monolayer of a 17‐mer thiol‐tethered DNA probe and a spacer thiol, 6‐mercapto‐1‐hexanol (MCH). An enzyme‐amplified detection scheme, based on the coupling of a streptavidin‐alkaline phosphatase conjugate and biotinylated target sequences was then applied. The enzyme catalyzed the hydrolysis of the electroinactive α‐naphthyl phosphate to α‐naphthol; this product is electroactive and has been detected by means of differential pulse voltammetry. In this way, the sensor coupled the unique electrical properties of polyaniline and gold nanoparticles (high surface area, fast heterogeneous electron transfer, chemical stability, and ease of miniaturisation) and enzymatic amplification. A linear response was obtained over a concentration range (0.2–10 nM). A detection limit of 0.1 nM was achieved. 相似文献
11.
Gold electrodes modified by underpotential deposition to expose a layer of silver atoms on their surfaces were used to measure thiocyanate concentrations in aqueous solutions. When exposed to thiocyanate, the ion adsorbs onto the modified electrode and causes changes in the electrochemical properties of the silver adlayer. Coulometric measurement of the fraction of the silver adlayer that remains in its original state provides a means for determining thiocyanate concentrations. The adsorption of thiocyanate onto the electrode follows a first‐order process with a rate constant of ca. 440 L/mol s that defines its concentration/time response. 相似文献
12.
Seil Akoullar Seda nar Kemal Volkan
zdokur Tülin Aydemir Fatma Nil Erta Süleyman Koak 《Electroanalysis》2020,32(2):445-453
Present study describes the synthesis of mixed oxide films of manganese and vanadium by electrochemical pulsed deposition technique on a glassy carbon electrode (GCE) modified with multiwall carbon nanotubes (MWCNT). The film was further decorated with gold nanoparticles to enhance the reduction signal of dissolved oxygen in pH 5.17 acetate buffer solution. All of the electrochemical synthesized modified electrodes have been characterized with Scanning electron microscopy(SEM), High‐resolution transmission electron microscopy (HRTEM), X‐Ray photoelectron spectroscopy (XPS), X‐Ray diffraction (XRD) techniques. The electrode obtained (AuNPs/MnOx?VOx/CNT/GCE) was utilized as a platform for glucose biosensor where the glucose oxidase enzyme was immobilized on the composite film with the aid of chitosan and an ionic liquid. The electrochemical performance of the biosensor was investigated by cyclic voltammetry and the relative parameters have been optimized by amperometric measurements in pH 5.17 acetate buffer solution. The developed biosensor exhibited a linear range for glucose between 0.1–1.0 mM and the limit of detection was calculated as 0.02 mM. 相似文献
13.
合成了聚苯胺纳米纤维,直径在50~70 nm之间;基于静电作用构建聚苯胺纳米纤维-纳米金复合膜界面,并在此界面上层层组装修饰叶酸分子,构建叶酸功能化传感界面,基于叶酸分子与癌细胞表面过量表达的叶酸受体之间的特异性识别作用,将此传感界面应用于对癌细胞的识别和捕获。结果表明:叶酸功能化传感界面能够特异性识别和捕获叶酸受体过量表达的癌细胞。采用电化学阻抗技术,以HeLa细胞为模型,应用于对癌细胞的识别和检测,细胞在1.0×104~6.4×106cells/mL浓度范围内与阻抗变化值ΔRct呈良好的线性关系;检出限为2000 cells/mL。本方法简单、快速灵敏、重现性和稳定性良好;制备的传感器可以再生使用。 相似文献
14.
15.
Electrocatalytic Oxidation of Tryptophan at Gold Nanoparticle‐Modified Carbon Ionic Liquid Electrode
The electrochemical behavior of tryptophan was studied at the carbon ionic liquid electrode (CILE) modified with gold nanoparticle (GNP). This electrode has a stable and excellent response toward tryptophan. Under optimum experimental conditions, the calibration curve was linear in the tryptophan concentration range of 5 to 900 µM with an excellent correlation coefficient (0.995). The experimental limit of detection was 4 µM. Contrary to many other electrodes, the oxidation of tryptophan on GNP/CILE does not result in electrode fouling. GNP/CILE has been effectively applied to the determination of tryptophan in composite amino acid injection. 相似文献
16.
17.
甲烷氧化菌素功能化纳米金修饰电极模拟SOD的电化学性能研究 总被引:1,自引:1,他引:0
利用混合自组装的方式,将Mb功能化纳米金(Mb-AuNPs-MUA)修饰在金电极表面,以制备出检测超氧阴离子无电子媒介体生物传感器.采用UV-Vis考察修饰纳米团簇的相关特征,利用修饰电极检测DMSO/NaOH体系产生的超氧阴离子.试验结果表明:该修饰电极对超氧阴离子的歧化反应具有显著的催化活性,计算出异相电子传递速率常数(Ks)为0.041 cm/s,电子转移系数(α)为0.435.在0.06~0.2 μmol/L范围内,超氧阴离子浓度与峰电流呈良好的线性关系,相关系数R2为0.9719,方法检出限(LOD)为1.129×10-3 μmol/L(S/N=3)、3.683×10-3 μmol/L(S/N=10),精密度试验测定得相对标准偏差(RSD,n=9)为3.83%. 相似文献
18.
报道了一种以金纳米粒子表面等离子吸收带变化为基础, 通过DNA与cis-Pt相互作用来检测溶液中cis-Pt浓度的新型比色法. 相似文献
19.
20.
Teresa Łuczak 《Electroanalysis》2008,20(12):1317-1322
A dopamine polymer film was prepared ex situ on a bare gold template from a 10 mM dopamine solution in phosphate buffer, pH 7 followed by an overoxidation in 500 mM NaOH. The modified electrode was used for quantitative determination of epinephrine. A linear relationship between epinephrine concentration and current response was obtained in the range between 2 μM and 800 μM with the detection limit of 0.3 μM. The results have shown that using the overoxidized dopamine film it is possible to perform electrochemical analysis of epinephrine without interference of ascorbic and uric acids. 相似文献