共查询到20条相似文献,搜索用时 15 毫秒
1.
In this paper, DNA–Cu2+ complex was electrodeposited onto the surface of glassy carbon (GC) electrode, which fabricated a DNA–Cu2+/GC electrode sensor to detect H2O2 with nonenzyme. Cyclic voltammogram of DNA–Cu2+/GC electrode showed a pair of well-defined redox peaks for Cu2+/Cu+. Moreover, the electrodeposited DNA–Cu2+ complex exhibited excellent electrocatalytic behavior and good stability for the detection of H2O2. The effects of Cu2+ concentration, electrodeposition time and determination conditions such as pH value, applied potential on the current response of the DNA–Cu2+/GC electrode toward H2O2 were optimized to obtain the maximal sensitivity. The linear range for the detection of H2O2 is 8.0 × 10−7 M to 4.5 × 10−3 M with a high sensitivity of −40.25 μA mM−1, a low detection limit of 2.5 × 10−7 M and a fast response time of within 4 s. In addition, the sensor has good reproducibility and long-term stability and is interference free. 相似文献
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Low-cost colorimetric sensor for the quantitative detection of gaseous hydrogen sulfide 总被引:2,自引:0,他引:2
Avijit Jeffrey D. James R. Patrick William B. 《Sensors and actuators. B, Chemical》2008,134(1):234-237
A simple, rapid and low-cost method for differentiating a wide range of concentrations of gaseous hydrogen sulfide (H2S) is described. A large dynamic range (50 ppb to 50 ppm) was successfully classified at ambient temperature using a colorimetric sensor array comprised of chemoresponsive dyes coupled to a commercially available 8-bit flatbed scanner. Principle component analysis of the composite magnitude and kinetics of color change for the array of dye spots over the entire dynamic range resulted in 100% classification. This was achieved by including chemoresponsive dyes which reacted specifically with H2S at different detection thresholds. 相似文献
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Pd/PVDF thin film hydrogen sensor system based on photopyroelectric purely-thermal-wave interference 总被引:1,自引:0,他引:1
Chinhua Wang Andreas Mandelis Jose A. Garcia 《Sensors and actuators. B, Chemical》1999,60(2-3):228-237
A novel sensitive solid-state sensor system for trace hydrogen gas detection has been developed as a next generation device to earlier photopyroelectric (PPE) hydrogen sensors. The basic principle of the sensor is based on the technique of PPE purely-thermal-wave interferometry recently developed in this Laboratory. The active element of the sensor is a thin polyvinylidene fluoride (PVDF) pyroelectric film, sputter-coated with Pd on one surface and with a Ni–Al alloy electrode on the other surface. Unlike the conventional PPE hydrogen sensors, this new sensor produces a coherent differential PPE signal in a single detector, rather than using two detectors (one active, the other reference) and complicated electronics. The measurement results show that the signal noise level, the detectivity and the signal dynamic range are improved by more than one order of magnitude compared with the conventional single-beam method. The operating characteristics have been examined for three different thicknesses of Pd coating on the same thickness PVDF-film detector. The signal generating mechanism, attributed to the change of the optical absorptance of the Pd coating when exposed to hydrogen, and/or the shift in the Pd work function, is also discussed. 相似文献
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Hemoglobin (Hb) was used as a template to fabricate hemoglobin–silver (Hb–Ag) sol in which the hemoglobin showed direct electrochemistry on a glass carbon (GC) electrode. Ultraviolet–visible (UV–vis) spectra and reflectance absorption infrared (RAIR) spectra suggested that hemoglobin in Hb–Ag sol retained its native secondary structure. Scanning electron microscopy (SEM) demonstrated that the morphology of the Hb film was much different from the Hb–Ag sol film. The Hb–Ag film proved to exhibit a good electrocatalytic activity for the reduction of hydrogen peroxide. Based on this, a novel amperometric hydrogen peroxide biosensor was developed, which showed a sensitive response to the reduction of H2O2 without any electron mediator. Under optimum conditions, the biosensor responded linearly to H2O2 in the concentration range of 1 × 10−6 to 2.5 × 10−2 M with detection limit of 1 × 10−7 M at 3σ. Moreover, the studied biosensor exhibited high sensibility, good reproducibility, and long-term stability. 相似文献
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Eui-Bok LeeAuthor VitaeIn-Sung HwangAuthor Vitae Jung-Ho ChaAuthor VitaeHo-Jun LeeAuthor Vitae Won-Bae LeeAuthor VitaeJames Jungho PakAuthor Vitae Jong-Heun LeeAuthor VitaeByeong-Kwon JuAuthor Vitae 《Sensors and actuators. B, Chemical》2011,153(2):392-397
An integrated catalytic combustion H2 sensor has been fabricated by using MEMS technology. Both the sensing elements and the reference elements could be integrated into the suspended micro heaters connected in a suitable circuit such as a Wheatstone configuration with low power consumption. Two sensitive elements and two reference sensors were integrated together onto a single chip. The size of chip was 5.76 mm2 and the catalytic combustion sensor showed high response to H2 at operating voltage of 1 V. The response and recovery times to 1000 ppm H2 were 0.36 s and 1.29 s, respectively. 相似文献
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The paper presents a simple and inexpensive method for the preparation of an efficient hydrogen gas sensor based on exfoliated Pd-decorated single-walled carbon nanotubes (SWNTs). SWNTs were synthesized by catalytic chemical vapor deposition of methane using a fixed-bed catalytic reactor over hydrides of Mm0.2Tb0.8Co2 obtained through hydrogen decrepitation technique. Purified and chemically treated SWNTs were functionalized with Pd, resulting in nanostructured Pd dispersion on the SWNT surface. Structural, morphological and vibrational characterizations were carried out using XRD, TEM, HRTEM, Raman spectroscopy and FTIR spectroscopy. Sensor devices were fabricated by spraying palladium-dispersed chemically treated SWNT dispersions on smooth glass substrates. Systematic investigations on the hydrogen sensing properties of Pd-SWNT were carried out. Pd-functionalization of the employed SWNT enabled increasing the device response towards hydrogen. Exfoliated SWNT achieved using gum arabic (GA) showed better response to hydrogen when compared to naive purified SWNT. The fabricated thin film sensors exhibited good reversible and reproducible response towards hydrogen at room temperature. 相似文献
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D. ZilliAuthor VitaeP.R. BonelliAuthor Vitae A.L. CukiermanAuthor Vitae 《Sensors and actuators. B, Chemical》2011,157(1):169-176
Multi-walled carbon nanotubes (MWCNTs) are successfully processed in the form of thin films (buckypapers), and their morphology and electrical behaviour are characterized. The MWCNTs are synthesized by the floating catalyst chemical vapour deposition process. The effects of a sequence of treatments applied for MWCNTs purification on the buckypapers electrical behaviour are also examined. Nanocomposite thin films constituted of pristine and purified MWCNTs and Pd nanoparticles are prepared in order to evaluate their viability as H2 sensors at room temperature. For this purpose, the electrical resistance of the nanocomposite films in atmospheres with different H2 concentrations, is determined. Scanning electron microscopy (SEM) images show that the buckypapers and the nanocomposite films are 2D structures constituted by randomly oriented MWCNTs. The buckypapers present a semiconductor-like electrical behaviour as determined by the standard four point method. Room temperature resistivity values of around 10−3 Ω m are assessed. Nanocomposite films show different electrical behaviour depending on the purification treatment applied to the MWCNTs employed. Furthermore, the electrical resistance of the nanocomposite films is found to increase when the measurements are performed in H2 atmosphere. Values of H2 sensitivity at room temperature of the nanocomposite films up to 2.15% are determined for H2 average concentration higher than 350 ppm with short recovery time. 相似文献
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Guillermina L. Nancy F. A. Gabriela Gustavo A. 《Sensors and actuators. B, Chemical》2009,142(1):331-336
This work proposes the amperometric determination of hydrogen peroxide reduction and oxidation as a tool for the characterization of La1−xAxMnO3 perovskites dispersed in a graphite composite electrode (carbon paste electrode, CPE). The catalytic activity of perovskites towards the oxidation and reduction of hydrogen peroxide is highly dependent on the nature of the A cation and on the temperature and time of calcination employed during the synthesis. Therefore, the selection of the optimal synthesis conditions to obtain the best catalytic activity towards hydrogen peroxide can be performed from amperometric determinations.We also report the analytical application of the perovskite modified CPE through the quantification of hydrogen peroxide in two real samples. Some preliminary results about the usefulness of La0.66Sr0.33MnO3–CPE to develop a glucose biosensor by incorporation of the enzyme glucose oxidase (GOx) within the electrode are also reported. The difference in sensitivity to glucose at CPE–GOx and CPE–La0.66Sr0.33MnO3–GOx (11.9 μA mol−1 L and 158.1 μA mol−1 L, respectively), clearly demonstrate the advantages of the association of the biocatalytic activity of GOx and the catalytic activity of perovskites towards hydrogen peroxide oxidation/reduction, and opens the doors to the development of new sensors for other important bioanalytes. 相似文献
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Duc-Duong LaAuthor VitaeChi Kwan KimAuthor Vitae Tae Sun JunAuthor VitaeYongju JungAuthor Vitae Gi Hun SeongAuthor VitaeJaebum ChooAuthor Vitae Yong Shin KimAuthor Vitae 《Sensors and actuators. B, Chemical》2011,155(1):191-198
Platinum nanoparticles (Pt NPs) were grown directly on multiwall carbon nanotubes (MWNTs) using a wet chemical reduction process. Gas permeable Pt NP-supported MWNT (Pt/MWNT) electrodes were then formed on microporous PTFE membranes through the vacuum-filtration of a Pt/MWNT solution. The potential use of these electrodes in amperometric hydrogen sensor applications was assessed. Various material analysis methods such as SEM, TEM and XRD were employed in order to characterize the morphologies and microstructures of the Pt/MWNT nanocomposites. The electrodes exhibited a nanoporous interwoven surface morphology as a result of Pt agglomerates attached to the MWNTs. From the XRD and TEM measurements, individual polygonal Pt NPs were confirmed to have polycrystalline face-centered cubic (fcc) structures and very small particle sizes of 2-7 nm. The electrode fabrication process was sequentially optimized by adjusting the MWNT content, H2PtCl6 concentration, NaBH4 concentration, and the drying temperature. At optimized conditions, the Pt/MWNT electrode displayed a high sensitivity greater than 200 μA/ppm, a fairly good selectivity to interfering CO species, and an excellent linear response over the wide concentration range of 5-1000 ppm. Furthermore, the performances of the electrodes were found to be better than those of binary NP-supported MWNT systems (Pt-Pd/MWNT, Pt-Zn/MWNT, Pt-Ni/MWNT and Pt-ZnO/MWNT). 相似文献
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基于四相检测技术的微电容传感器 总被引:8,自引:4,他引:8
一种基于四相检测技术的电荷转移式微电容传感器,具有很强的消除杂散电容影响的能力,适用于被检测对象电容值小于1pF的场合,分辨力达1fF,灵敏度高于1V/pF,并能输出4~20mA的电流。其优良的性能和低廉的价格,使得微电容传感器的广泛推广应用成为可能。 相似文献
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Solvatochromic effects in the UV/VIS spectra of dyes can be applied to the monitoring of solvents in the gaseous phase. Within the class of solvatochromic dyes Reichhardt's betaine reveals an outstanding hypsochromic effect on protic solvents with a band shift of up to 350 nm. For vapor detection, the sensor behavior was optimized according to the linearity of the response signal, the sensitivity and a minimum influence of humidity by hydrophobizing siloxanes as additives. Furthermore, the dyes were immobilized under mild conditions by a sol–gel process which generates a high porosity for easy analyte access. The detection principle could be further extended to aprotic, polar solvents by embedding the dyes in protic matrices that form hydrogen bonds to the betaine oxygen. Then, the analyte disturbs the hydrogen bonds resulting in a bathochromic band shift resembling a back titration. Finally, the betaine phenol blue even allows the detection of halogenated hydrocarbons that lack a pronounced functionality but nonetheless a hyperchromic effect occurs during analyte exposition. Mechanistic aspects of these solvent absorption processes were traced by mass-sensitive measurements. 相似文献
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Kuo-Chiang LinAuthor VitaeChien-Yu YinAuthor Vitae Shen-Ming ChenAuthor Vitae 《Sensors and actuators. B, Chemical》2011,157(1):202-210
An electrochemical biosensor for determination of hydrogen peroxide (H2O2) has been developed by the hybrid film of poly(methylene blue) and FAD (PMB/FAD). The PMB/FAD hybrid film was performed in PBS (pH 7) containing methylene blue and FAD by cyclic voltammetry. Repeatedly scanning potential range of −0.6-1.1 V, FAD was immobilized on the electrode surface by electrostatic interaction while methylene blue was electropolymerized on electrode surface. This modified electrode was found surface confined and pH dependence. It showed good electrocatalytic reduction for H2O2, KBrO3, KIO3, and NaClO as well as electrocatalytic oxidation for NADH. At an applied potential of −0.45 V vs. Ag/AgCl, the sensor showed a rapid and linear response to H2O2 over the range from 0.1 μM to 960 μM, with a detection limit of 0.1 μM and a significant sensitivity of 1109 μA mM−1 cm−2 (S/N = 3). It presented excellent stability at room temperature, with a variation of response current less than 5% over 30 days. 相似文献
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采用混合组装技术,利用植酸胶束(IP6micelles)的磷酸酯键络合辣根过氧化物酶(HRP)和金纳米粒子(GNPs),形成了具有生物亲和性的纳米复合材料,保持了辣根过氧化物酶的生物活性,并利用金纳米粒子的高电子密度、介电特性和催化性能,实现了HRP与玻碳电极(GCE)表面的直接电子转移。Nafion膜的滴加能提高电极的选择性和稳定性。实验过程中借助紫外-可见吸收光谱和透射电子显微镜进行表征,实验结果证明:GNPs的高导电和高催化性能,结合植酸胶束的优良生物相容性和对酶的高负载量的特点,使得吸附在其上的HRP保持活性,制备的生物传感器能对H2O2进行电催化还原。Nafion/HRP-IP6micelles-GNPs/GCE对H2O2的线性浓度范围为5×10-7~1.15×10-5mol/L(线性相关系数r=0.993,n=9),最低检测限为0.1μmol/L(信噪比S/N=3),米氏常数为0.002 4 mmol/L。 相似文献
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基于气体传感器阵列的动态检测系统 总被引:3,自引:0,他引:3
描述了一个基于传感器阵列的气体检测系统,其阵列由6只气体传感器组成。系统采用较以往静态加热所不同的动态加热方式,重点介绍了该系统的硬件结构。通过分析系统的气体响应特性实验得出:该系统具有静态测试所不具备的许多优点,如,信号特征多、容易识别等。 相似文献