A new issue of this journal has just been published. To see abstracts of the papers it contains (with links through to the full papers) click here:
Selected papers from the latest issue:
Comparison of nitric oxide binding to different pure and mixed protoporphyrin IX monolayers
06 March 2012, 02:35:51
Publication year: 2012
Source: Sensors and Actuators B: Chemical, Available online 5 March 2012
Wout Knoben, Mercedes Crego-Calama, Sywert H. Brongersma
The nitric oxide (NO) binding properties of monolayers of four different protoporphyrins IX adsorbed on aluminum oxide surfaces have been investigated. XPS and AFM results are consistent with the presence of a monolayer of porphyrins, bound to the surface by their carboxylic acid groups and with the porphine ring oriented more or less perpendicular to the surface. Kelvin probe measurements were done in which the samples were exposed to varying NO concentrations. NO binds strongly to all porphyrins, but protoporphyrin IX zinc(II) (Zn-PP) shows the most promising response. The response rate could be increased by adding spacer molecules to the porphyrin layer. Low ppb levels of NO were easily detected in ambient conditions. The NO binding properties of Zn-PP compare favorably to those of other porphyrins which were previously used for NO sensing. This makes Zn-PP a new and promising candidate for this application.
Source: Sensors and Actuators B: Chemical, Available online 5 March 2012
Wout Knoben, Mercedes Crego-Calama, Sywert H. Brongersma
The nitric oxide (NO) binding properties of monolayers of four different protoporphyrins IX adsorbed on aluminum oxide surfaces have been investigated. XPS and AFM results are consistent with the presence of a monolayer of porphyrins, bound to the surface by their carboxylic acid groups and with the porphine ring oriented more or less perpendicular to the surface. Kelvin probe measurements were done in which the samples were exposed to varying NO concentrations. NO binds strongly to all porphyrins, but protoporphyrin IX zinc(II) (Zn-PP) shows the most promising response. The response rate could be increased by adding spacer molecules to the porphyrin layer. Low ppb levels of NO were easily detected in ambient conditions. The NO binding properties of Zn-PP compare favorably to those of other porphyrins which were previously used for NO sensing. This makes Zn-PP a new and promising candidate for this application.
A highly sensitive nitric oxide biosensor based on hemoglobin-chitosan/graphene-hexadecyltrimethylammonium bromide nanomatrix
06 March 2012, 02:35:51
Publication year: 2012
Source: Sensors and Actuators B: Chemical, Available online 5 March 2012
Wei Wen, Wei Chen, Qiong-Qiong Ren, Xiao-Yan Hu, Hua-Yu Xiong, ...
Nitric oxide (NO) is a key signaling molecule in different physiological processes of plants. It is therefore very important to establish a simple, fast, sensitive and accurate detection method for NO detection. In this study, a novel amperometric biosensor based on immobilization of hemoglobin (Hb), chitosan (CS), graphene (GR) and the surfactant hexadecyltrimethylammonium bromide (CTAB) on a glassy carbon electrode was constructed to quantitatively measure NO. Atomic force microscopy, scanning electron microscopy and electrochemical methods were used to characterize the Hb-CS/GR-CTAB nanocomposite film. The biosensor fabricated from the nanocomposite film showed direct electrochemistry with a fast electron-transfer rate (60.3 s) and high electrocatalytic activity towards the reduction of NO. Under optimal conditions, the resulting biosensor exhibited a high sensitivity of 615 μA mM, a low detection limit of 6.75 × 10 M (S/N = 3) and a small apparent Michaelis-Menten constant of 0.315 μM. These results were superior to those for biosensors based on the graphite, GR/ionic liquid and carbon nanotubes. The biosensor was also used successfully for detection of additional NO in oilseed rape leaf homogenate samples. Furthermore, the biosensor had excellent long-term storage stability, as well as reproducibility and selectivity, and should have a potential application in monitoring NO in plant samples.
Source: Sensors and Actuators B: Chemical, Available online 5 March 2012
Wei Wen, Wei Chen, Qiong-Qiong Ren, Xiao-Yan Hu, Hua-Yu Xiong, ...
Nitric oxide (NO) is a key signaling molecule in different physiological processes of plants. It is therefore very important to establish a simple, fast, sensitive and accurate detection method for NO detection. In this study, a novel amperometric biosensor based on immobilization of hemoglobin (Hb), chitosan (CS), graphene (GR) and the surfactant hexadecyltrimethylammonium bromide (CTAB) on a glassy carbon electrode was constructed to quantitatively measure NO. Atomic force microscopy, scanning electron microscopy and electrochemical methods were used to characterize the Hb-CS/GR-CTAB nanocomposite film. The biosensor fabricated from the nanocomposite film showed direct electrochemistry with a fast electron-transfer rate (60.3 s) and high electrocatalytic activity towards the reduction of NO. Under optimal conditions, the resulting biosensor exhibited a high sensitivity of 615 μA mM, a low detection limit of 6.75 × 10 M (S/N = 3) and a small apparent Michaelis-Menten constant of 0.315 μM. These results were superior to those for biosensors based on the graphite, GR/ionic liquid and carbon nanotubes. The biosensor was also used successfully for detection of additional NO in oilseed rape leaf homogenate samples. Furthermore, the biosensor had excellent long-term storage stability, as well as reproducibility and selectivity, and should have a potential application in monitoring NO in plant samples.
A Breakthrough in Gas Diagnosis with a Temperature-Modulated Generic Metal Oxide Gas Sensor
06 March 2012, 02:35:51
Publication year: 2012
Source: Sensors and Actuators B: Chemical, Available online 5 March 2012
Faramarz Hossein-Babaei, Amir Amini
Sharp operating temperature fluctuations in an analyte-exposed gas sensor result in temporal responses containing considerable amounts of extractable analyte-related information. Due to their high thermal capacity, applying step heating voltages fails to provide step temperature variations in generic metal oxide gas sensors. On the other hand, the custom-made low thermal capacity sensors are vulnerable to thermal noise and environmental agitations in field applications. A novel technique is reported here for inducing the sharp pallet temperature rises required for obtaining selective responses in commonly used bulk tin oxide gas sensors, affording the gas discrimination capacity sought after since the advent of these typically non-selective, though user friendly, devices. In this technique, a voltage spike surpassing the nominal heating voltage of the device is applied prior to a voltage step. The thermal impact of the spike is adjusted to obtain step-like temperature profiles with rise times less than 1/10 of the sensor thermal time-constant. The temporal responses recorded for 12 different airborne analytes, each in a wide concentration range, appear different enough to identify contaminants with minimal computational cost. Analyte examination and recognition take only 4 s. In addition to analyte discrimination, the fabricated prototype also classifies the analytes in terms of their molecular structures of, for example, alcohols and ketones. This single-sensor gas diagnosis device is presented as a potential replacement for array-based electronic nose systems in a number of applications.
Source: Sensors and Actuators B: Chemical, Available online 5 March 2012
Faramarz Hossein-Babaei, Amir Amini
Sharp operating temperature fluctuations in an analyte-exposed gas sensor result in temporal responses containing considerable amounts of extractable analyte-related information. Due to their high thermal capacity, applying step heating voltages fails to provide step temperature variations in generic metal oxide gas sensors. On the other hand, the custom-made low thermal capacity sensors are vulnerable to thermal noise and environmental agitations in field applications. A novel technique is reported here for inducing the sharp pallet temperature rises required for obtaining selective responses in commonly used bulk tin oxide gas sensors, affording the gas discrimination capacity sought after since the advent of these typically non-selective, though user friendly, devices. In this technique, a voltage spike surpassing the nominal heating voltage of the device is applied prior to a voltage step. The thermal impact of the spike is adjusted to obtain step-like temperature profiles with rise times less than 1/10 of the sensor thermal time-constant. The temporal responses recorded for 12 different airborne analytes, each in a wide concentration range, appear different enough to identify contaminants with minimal computational cost. Analyte examination and recognition take only 4 s. In addition to analyte discrimination, the fabricated prototype also classifies the analytes in terms of their molecular structures of, for example, alcohols and ketones. This single-sensor gas diagnosis device is presented as a potential replacement for array-based electronic nose systems in a number of applications.
Capacitive humidity sensing properties of SiC nanowires grown on silicon nanoporous pillar array
06 March 2012, 02:35:51
Publication year: 2012
Source: Sensors and Actuators B: Chemical, Available online 5 March 2012
Hai Yan Wang, Yong Qiang Wang, Qing Fei Hu, Xin Jian Li
A large quantity of entangled SiC nanowires (nw-SiC) with an average diameter of ∼15 nm were grown on a silicon nanoporous pillar array (Si-NPA) by a catalyst-assisted chemical vapor deposition method. The room-temperature capacitive humidity sensing properties ofnw-SiC/Si-NPA were studied by evaporating coplanar interdigital silver electrodes onto its surface. With the relative humidity (RH) changing from 11% to 95%, a capacitance increment over 960% was achieved at the measuring frequency of 100 Hz. The response and recovery times were measured to be ∼105 and 85 seconds, respectively, with a maximum humidity hysteresis of 4.5% at 75% RH. The humidity sensor was also proved to be with high measurement reproducibility and long-term stability. Our results indicate that one-dimensional SiC materials might be competitive as a novel sensing material for fabricating humidity sensors with high performances.
Source: Sensors and Actuators B: Chemical, Available online 5 March 2012
Hai Yan Wang, Yong Qiang Wang, Qing Fei Hu, Xin Jian Li
A large quantity of entangled SiC nanowires (nw-SiC) with an average diameter of ∼15 nm were grown on a silicon nanoporous pillar array (Si-NPA) by a catalyst-assisted chemical vapor deposition method. The room-temperature capacitive humidity sensing properties ofnw-SiC/Si-NPA were studied by evaporating coplanar interdigital silver electrodes onto its surface. With the relative humidity (RH) changing from 11% to 95%, a capacitance increment over 960% was achieved at the measuring frequency of 100 Hz. The response and recovery times were measured to be ∼105 and 85 seconds, respectively, with a maximum humidity hysteresis of 4.5% at 75% RH. The humidity sensor was also proved to be with high measurement reproducibility and long-term stability. Our results indicate that one-dimensional SiC materials might be competitive as a novel sensing material for fabricating humidity sensors with high performances.
Differential pulse voltammetric analysis of lead in vegetables using a surface amino-functionalized exfoliated graphite nanoplatelet chemically modified electrode
06 March 2012, 02:35:51
Publication year: 2012
Source: Sensors and Actuators B: Chemical, Available online 5 March 2012
Ion Ion, Alina Catrinel Ion
A surface amino-functionalized (-CO-NH2) exfoliated graphite nanoplatelet (xGnP) bismuth-modified electrode (-CO-NH2-xGnP/glassy carbon electrode GCE) for the determination of lead was developed and characterized. The hybrid material was characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The electrochemical properties of the -CO-NH2–xGnP bismuth-modified electrode were characterized by a physical deposition method, depositing the film on a graphite electrode. The differential pulse response was linear over the Pb(II) concentration range of 0.005–0.045 μg L, with a limit of detection of 0.001 μg L, and the linear regression equation was y = 3.75x + 0.73. In vegetable juice (cabbage), the current increased linearly relative to the Pb(II) concentrations over the concentration range 0.005 to 0.035 μg Lwith the corresponding linear regression equations: y = 13.06x + 0.46, R = 0.9970.
Source: Sensors and Actuators B: Chemical, Available online 5 March 2012
Ion Ion, Alina Catrinel Ion
A surface amino-functionalized (-CO-NH2) exfoliated graphite nanoplatelet (xGnP) bismuth-modified electrode (-CO-NH2-xGnP/glassy carbon electrode GCE) for the determination of lead was developed and characterized. The hybrid material was characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The electrochemical properties of the -CO-NH2–xGnP bismuth-modified electrode were characterized by a physical deposition method, depositing the film on a graphite electrode. The differential pulse response was linear over the Pb(II) concentration range of 0.005–0.045 μg L, with a limit of detection of 0.001 μg L, and the linear regression equation was y = 3.75x + 0.73. In vegetable juice (cabbage), the current increased linearly relative to the Pb(II) concentrations over the concentration range 0.005 to 0.035 μg Lwith the corresponding linear regression equations: y = 13.06x + 0.46, R = 0.9970.
Effect of pH on the morphology and gas sensing properties of ZnO nanostructures
06 March 2012, 02:35:51
Publication year: 2012
Source: Sensors and Actuators B: Chemical, Available online 5 March 2012
Onkar Singh, Manmeet Pal Singh, Nipin Kohli, Ravi Chand Singh
Morphology dependent gas sensing behaviour of zinc oxide has been reported in this paper. Nanostructures of zinc oxide have been synthesized by following a precipitation route at various pH values of the precursor solution. Structural and morphological analyses were carried out by using XRD and FESEM techniques. The XRD pattern confirmed wurtzite hexagonal structure of ZnO. The FESEM study revealed that ZnO synthesized at pH 8 developed nanorod like structure, rods got fused together when synthesized at pH 9 and 10, whereas synthesis at pH 11 resulted in transformation of rods into nanoparticles. The thick films of synthesized samples were deposited on alumina substrate and their sensing response to methanol, ethanol and propanol was investigated at different operating temperatures. It was observed that all the sensors exhibited optimum sensing response at 400 °C. It has also been observed that sample prepared at pH 11, constituting nanoparticles, exhibited high sensing response than an assembly of nanorods prepared at pH 8-10. Sensing response of all the samples tested was significantly higher towards propanol vapour than towards that of methanol and ethanol.
Source: Sensors and Actuators B: Chemical, Available online 5 March 2012
Onkar Singh, Manmeet Pal Singh, Nipin Kohli, Ravi Chand Singh
Morphology dependent gas sensing behaviour of zinc oxide has been reported in this paper. Nanostructures of zinc oxide have been synthesized by following a precipitation route at various pH values of the precursor solution. Structural and morphological analyses were carried out by using XRD and FESEM techniques. The XRD pattern confirmed wurtzite hexagonal structure of ZnO. The FESEM study revealed that ZnO synthesized at pH 8 developed nanorod like structure, rods got fused together when synthesized at pH 9 and 10, whereas synthesis at pH 11 resulted in transformation of rods into nanoparticles. The thick films of synthesized samples were deposited on alumina substrate and their sensing response to methanol, ethanol and propanol was investigated at different operating temperatures. It was observed that all the sensors exhibited optimum sensing response at 400 °C. It has also been observed that sample prepared at pH 11, constituting nanoparticles, exhibited high sensing response than an assembly of nanorods prepared at pH 8-10. Sensing response of all the samples tested was significantly higher towards propanol vapour than towards that of methanol and ethanol.
A novel nonenzymatic hydrogen peroxide sensor based on reduced graphene oxide/ZnO composite modified electrode
06 March 2012, 02:35:51
Publication year: 2012
Source: Sensors and Actuators B: Chemical, Available online 3 March 2012
Selvakumar Palanisamy, Shen-Ming Chen, R. Saraswathi
A novel nonenzymatic, amperometric sensor for hydrogen peroxide (H2O2) was developed based on an electrochemically prepared reduced graphene oxide (RGO)/zinc oxide (ZnO) composite using a simple and cost effective approach. RGO/ZnO composite was fabricated on a glassy carbon (GCE) electrode by a green route based on the electrodeposition of ZnO on graphene oxide (GO). The morphology of the as-prepared RGO/ZnO composite was investigated by scanning electron microscopy (SEM). Attenuated total reflectance (ATR) spectroscopy has also been performed to confirm the ample reduction of oxygen functionalities located at graphene oxide (GO). The electrochemical performance of the RGO/ZnO composite modified GCE was studied by amperometric technique, and the resulting electrode displays excellent performance towards hydrogen peroxide (H2O2) at -0.38 V in the linear response range from 0.02–22.48 μM, with a correlation coefficient of 0.9951, and short response time (<5 s). The proposed sensor also has good operational and storage stability with appreciable anti-interferring ability.
Source: Sensors and Actuators B: Chemical, Available online 3 March 2012
Selvakumar Palanisamy, Shen-Ming Chen, R. Saraswathi
A novel nonenzymatic, amperometric sensor for hydrogen peroxide (H2O2) was developed based on an electrochemically prepared reduced graphene oxide (RGO)/zinc oxide (ZnO) composite using a simple and cost effective approach. RGO/ZnO composite was fabricated on a glassy carbon (GCE) electrode by a green route based on the electrodeposition of ZnO on graphene oxide (GO). The morphology of the as-prepared RGO/ZnO composite was investigated by scanning electron microscopy (SEM). Attenuated total reflectance (ATR) spectroscopy has also been performed to confirm the ample reduction of oxygen functionalities located at graphene oxide (GO). The electrochemical performance of the RGO/ZnO composite modified GCE was studied by amperometric technique, and the resulting electrode displays excellent performance towards hydrogen peroxide (H2O2) at -0.38 V in the linear response range from 0.02–22.48 μM, with a correlation coefficient of 0.9951, and short response time (<5 s). The proposed sensor also has good operational and storage stability with appreciable anti-interferring ability.
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