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991.
Jing LiAuthor VitaeHuaqing XieAuthor Vitae Lifei ChenAuthor Vitae 《Sensors and actuators. B, Chemical》2011,153(1):239-245
A highly sensitive hydrazine sensor was developed based on the electrodeposition of gold nanoparticles onto the choline film modified glassy carbon electrode (GNPs/Ch/GCE). The electrochemical experiments showed that the GNPs/Ch film exhibited a distinctly higher activity for the electro-oxidation of hydrazine than GNPs with 3.4-fold enhancement of peak current. The kinetic parameters such as the electron transfer coefficient (α) and the rate of electron exchange (k) for the oxidation of hydrazine were determined. The diffusion coefficient (D) of hydrazine in solution was also calculated by chronoamperometry. The sensor exhibited two wide linear ranges of 5.0 × 10−7-5.0 × 10−4 and 5.0 × 10−4-9.3 × 10−3 M with the detection limit of 1.0 × 10−7 M (s/n = 3). The proposed electrode presented excellent operational and storage stability for the determination of hydrazine. Moreover, the sensor showed outstanding sensitivity, selectivity and reproducibility properties. All the results indicated a good potential application of this sensor in the detection of hydrazine. 相似文献
992.
Siming LiuAuthor VitaeRuo YuanAuthor Vitae Yaqin ChaiAuthor VitaeHuilan SuAuthor Vitae 《Sensors and actuators. B, Chemical》2011,156(1):388-394
In this work, a novel label-free amperometric immunosensor has been constructed for detecting α-1-fetoprotein (AFP) based on nanocomposite of horseradish peroxidase (HRP) labeled carbon nanotubes (CNTs). First, the gold nanoparticles (AuNPs) were electrodeposited on the surface of the glass carbon electrode by electrochemical reduction of gold chloride tetrahydrate (HAuCl4) to immobilize horseradish peroxidase labeled carbon nanotubes (HRP-CNTs). Then HRP-CNTs bioconjugate was immobilized on the surface of the electrodeposited AuNPs layer by the combination of forces (coordination and electrostatic force). Subsequently, it was immersed into gold colloidal nanoparticles (GNPs) solution, which was used to immobilize antibody biomolecules (anti-AFP). Enhanced sensitivity was obtained by using bioconjugates featuring HRP labeled (HRP-CNTs), which had lager specific surface area and good electronic catalysis (current response signal) compared to carbon nanotubes. Under optimized conditions, the linear ranges were from 0.2 to 200 ng mL−1 with a detection limit of 0.067 ng mL−1 (at an S/N of 3). The proposed immunosenor showed good precision, acceptable stability and reproducibility and could be used for the detection AFP in normal human serum, which provided a potential alternative tool for the detection of protein in clinical diagnosis. 相似文献
993.
Hiroyuki YamauraAuthor VitaeYuji IwasakiAuthor Vitae Shinsuke HiraoAuthor VitaeHidenori YahiroAuthor Vitae 《Sensors and actuators. B, Chemical》2011,153(2):465-467
The CO sensing property of CuO-loaded SnO2-In2O3 sensor was investigated in a reducing atmosphere. The sensor response to CO for CuO/SnO2-In2O3 (8/2) was much higher than that for CuO/SnO2 in the range of 200-1000 ppm of CO concentration. Such a high sensor response of CuO/SnO2-In2O3 may originate from the high dispersion of CuO playing a role as sensing site. 相似文献
994.
Alessio GibertiAuthor Vitae Vincenzo Guidi Author VitaeDonato Vincenzi Author Vitae 《Sensors and actuators. B, Chemical》2011,153(2):409-414
A micromachined chemoresistive gas sensor was studied from the point of view of heat distribution and thermal dissipation: this innovative device for environmental pollutant gas monitoring, is based on a sensitive film of semiconductor metal oxides, kept in temperature by a platinum resistor. In order to avoid electrical interactions between the film heater and the contacts for the film reading, the heater is driven by a square wave, and the film is read when no voltage is provided. Since the working temperature of the film is extremely important for its operation, it is crucial to maintain the temperature fluctuations within few degrees; to this end, in this work we study the heat distribution and dissipation of such a device, aiming to set a proper heating frequency, which will assure a right stability of the working temperature. 相似文献
995.
Study on design and application of fully automatic miniature surface plasmon resonance concentration analyzer 总被引:1,自引:0,他引:1
Shuyue ZhanAuthor VitaeXiaoping WangAuthor Vitae Zhaofeng LuoAuthor VitaeHongmin ZhouAuthor Vitae Huibin ChenAuthor VitaeYuling LiuAuthor Vitae 《Sensors and actuators. B, Chemical》2011,153(2):427-433
A fully automatic miniature surface plasmon resonance (SPR) concentration analyzer having high performance and low cost and developed using a Spreeta™ sensor was designed for field applications and concentration analysis. As in the case of Biacore™ instruments, the automatic sampling system of this device can introduce air segments between the sample/regeneration solution and buffer solution in the pipeline, which effectively prevents mixing of the solutions. A temperature sensor (AD 590) and temperature compensation method are used, which make the device insensitive to temperature fluctuations. A real-time data-smoothing algorithm for the SPR detection data is adopted; this can reduce the noise level to 5 × 10−7 RIU (refractive index units). The noise level of the sensorgram is 3.5% of the original level. Two types of self-prepared sensing chips—SMX-BSA (bovine serum albumin coated with sulfamethoxazole) and SMX-CM5 (carboxymethyl dextran coated with sulfamethoxazole)—are used to analyze the concentrations of sulfamethoxazole (SMX) standard solutions. Each chip's SMX calibration curve is established within the measurement range of 0-2000 ng/ml, and both limits of detection (LOD) are 2 ng/ml. One cycle of assay time is less than 15 min. 相似文献
996.
Xiaotun QiuAuthor VitaeRui TangAuthor Vitae Jie ZhuAuthor VitaeJon OilerAuthor Vitae Cunjiang YuAuthor VitaeZiyu WangAuthor Vitae Hongyu YuAuthor Vitae 《Sensors and actuators. B, Chemical》2011,151(2):360-364
This study investigated the influence of temperature, relative humidity and reducing gases on the ultraviolet (UV) response of ZnO based film bulk acoustic-wave resonator (FBAR). As temperature increased, the UV response of the FBAR degraded. This was attributed to the softening of the ZnO film with increasing temperature. Water molecules can replace adsorbed oxygen on the ZnO surface. At high relative humidity, more oxygen was replaced by water. In this way, the density of the ZnO film increased and less oxygen was left on the surface to be desorbed by UV, both of which contributed to a lower UV response. Reducing gases, such as acetone, can react with the surface adsorbed oxygen and reduce the density of the ZnO film, resulting in UV response degradation. 相似文献
997.
Syed M. Usman AliAuthor Vitae N.H. AlviAuthor VitaeZafar IbupotoAuthor Vitae Omer NurAuthor VitaeMagnus WillanderAuthor Vitae Bengt DanielssonAuthor Vitae 《Sensors and actuators. B, Chemical》2011,152(2):241-247
In this study, a potentiometric uric acid biosensor was fabricated by immobilization of uricase onto zinc oxide (ZnO) nanowires. Zinc oxide nanowires with 80-150 nm in diameter and 900 nm to 1.5 μm in lengths were grown on the surface of a gold coated flexible plastic substrate. Uricase was electrostatically immobilized on the surface of well aligned ZnO nanowires resulting in a sensitive, selective, stable and reproducible uric acid biosensor. The potentiometric response of the ZnO sensor vs Ag/AgCl reference electrode was found to be linear over a relatively wide logarithmic concentration range (1-650 μM) suitable for human blood serum. By applying a Nafion® membrane on the sensor the linear range could be extended to 1-1000 μM at the expense of an increased response time from 6.25 s to less than 9 s. On the other hand the membrane increased the sensor durability considerably. The sensor response was unaffected by normal concentrations of common interferents such as ascorbic acid, glucose, and urea. 相似文献
998.
Ting XuAuthor VitaeJianmin MiaoAuthor Vitae Zhihong WangAuthor VitaeLing YuAuthor Vitae Chang Ming LiAuthor Vitae 《Sensors and actuators. B, Chemical》2011,151(2):370-376
In this paper, a piezoelectric diaphragm-based immunoassay chip was developed to simultaneously detect anti-Hepatitis B virus (HBV) and anti-alpha-fetoprotein (AFP). The chip was fabricated by micro-machining technology and consists of eight individual circular sensors with a diameter of 800 μm. Hepatitis B surface antigen (HBsAg), Hepatitis C core antigen (HBcAg) and AFP as the probe molecules were immobilized on different sensing spots on the chip. A solution containing anti-HBsAg and anti-AFP was applied into the reaction chambers in all sensors of the chip, and significant frequency shifts were only observed in the sensors with HBsAg and AFP for immunoassay detection. The fluorescence image further confirmed the successful detection of anti-HBsAg and anti-AFP. The total assay time was less than 2 h. The frequency shift-based calibration curves show a detection limit of 0.1 ng/ml and a dynamic detection range of 0.1-10,000 ng/ml for both anti-HBsAg and anti-AFP, respectively, thus demonstrating that the developed piezoelectric immunoassay chip has potential applications for rapid, specific, sensitive, and multiple detections of HBV. 相似文献
999.
Pi-Guey SuAuthor Vitae Chuen-Chi ShiuAuthor Vitae 《Sensors and actuators. B, Chemical》2011,157(1):275-281
A novel flexible H2 gas sensor was fabricated by the layer-by-layer (LBL) self-assembly of a polypyrrole (PPy) thin film on a polyester (PET) substrate. A Pt-based complex was self-assembled in situ on the as-prepared PPy thin film, which was reduced to form a Pt-PPy thin film. Microstructural observations revealed that Pt nanoparticles formed on the surface of the PPy film. The sensitivity of the PPy thin film was improved by the Pt nanoparticles, providing catalytically active sites for H2 gas molecules. The interfering gas NH3 affected the limit of detection (LOD) of a targeted H2 gas in a real-world binary gas mixture. A plausible H2 gas sensing mechanism involves catalytic effects of Pt particles and the formation of charge carriers in the PPy thin film. The flexible H2 gas sensor exhibited a strong sensitivity that was greater than that of sensors that were made of Pd-MWCNTs at room temperature. 相似文献
1000.
Yan-Ling LuoAuthor Vitae Bi-Xia WangAuthor VitaeFeng XuAuthor Vitae 《Sensors and actuators. B, Chemical》2011,156(1):12-22
A series of multi-walled carbon nanotubes/polyurethane (MWNTs/PU) composite conducting dispersoids were prepared via an in situ coupling reaction among linear hydroxyl-terminated polymer diols, 1,6-hexamethylene diisocyanate (HDI) and various chain extenders. The composite conducting thin films were formed by spin-coating and depositing the dispersoids onto comb-like electrode substrates. The resulting structure and the dispersion quality of MWNTs in the dispersoids were examined by means of FTIR, XRD, TEM, SEM and UV-vis analyses. The response of the as-prepared films toward some volatile organic solvent vapors such as benzene, anhydrous ether, acetone and chloroform was evaluated. The experimental results indicated that the composite conducting films constructed by hydroxyl-terminated poly(butadiene-co-acrylonitrile), trimethylolpropane, and MWNTs-OH bear better vapor responsiveness. The dispersion behavior of MWNTs in the dispersoids, types of MWNTs and soft-hard segmental compositions are believed to be closely related with the sensing properties of the films. In particular, the chemical linkage of MWNT-OH with HDI in the PU matrix is expected to improve the dispersivity and further to enhance the sensing properties of the composite sensors. The vapor sensing properties well reveal that these materials have a possibility as a candidate of volatile organic solvent vapor sensors. 相似文献