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Proceedings ArticleDOI

Metal Oxide Semiconductor-based gas sensor for Acetone sensing

TL;DR: In this article, a portable and sensitive metal oxide semiconductor-based gas sensor with Tungsten Oxide (WO 3 ) thin film as the sensing layer has been used to measure the concentration of Acetone in breath.
Abstract: Acetone constitutes 58% of the volatile organic compounds found in human breath. Acetone in breath is proven to be a biomarker for type I diabetes. Portable and sensitive metal oxide semiconductor-based gas sensor with Tungsten Oxide (WO 3 ) thin film as the sensing layer has been used to measure the concentration of Acetone in breath. Acetone gas being a reducing gas decreases the resistance of thin film when it comes in contact of the sensor. The gas sensor is fabricated, characterized and tested for various concentrations of Acetone gas. A linear calibration curve is obtained on the log scale for predicting any concentration in the novel range of 10 ppm to 300 ppm at 300 °C in the sensor fabricated using RF Magnetron sputtering method. The gas sensor is portable and easy to handle with the chip size of 5mm × 5mm and thin film thickness of 100 nm. The efficiency is optimized by operating it at temperature 300 °C with minimum response time and recovery time
Citations
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Journal ArticleDOI
TL;DR: In this article, two resistive sensors based on reduced graphene oxide (RGO) and RGO- rosebengal (RB) composites were used for the selective determination of three organic vapors.
Abstract: This work reports a new technique for the selective determination of three organic vapors– ammonia, ethanol and acetone by employing two resistive sensors. These two resistive sensors are based on reduced graphene oxide (RGO) and RGO– rosebengal (RB) composites. The chemically synthesized RGO and RGO–RB based sensors were tested for four different concentrations of ammonia (400–2800 ppm) and two different concentrations (1000, 2000 ppm) of ethanol and acetone each, at room temperature. The RGO sensor was found to exhibit response of 10.3% to 25.3% to 400–2800 ppm of ammonia, 1.01% to 1.15% to 1000 and 2000 ppm of acetone respectively, and 1.05% to 1.56% to 1000 and 2000 ppm of ethanol respectively. The RGO–RB composite-based sensor exhibited an enhanced response ranging from ~17% to 36.6% for 400–2800 ppm of ammonia, 1.6% to 3.2% for 1000 and 2000 ppm of acetone and 1.1% to 1.7% for 1000 and 2000 ppm of ethanol at room temperature. An algorithm, based on the soft margin classifier was developed to accurately determine the concentrations of all the three organic vapors. The initial 100 s of the response values of both the sensors for all the targeted vapors were considered for this purpose. This resulted into classification of all the concentrations of the three organic vapors much before the full-scale response of the sensors. It is believed that this work will aid in development of portable devices comprising of array of sensors having the capability of determining the vapors and their concentrations accurately.

24 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of doping on the performance of tungsten oxide (WO3) based supercapacitor was analyzed in different electrolytes (H+, Li, Na+, Ca2+ and Al3+).

18 citations

Journal ArticleDOI
TL;DR: In this article , a review of the state of the art of the main MOx-type sensors in the detection of acetone vapors is presented to propose future perspectives and directions that should be carried out to implement this type of sensor in the field of medicine.
Abstract: Metal oxide (MOx) gas sensors have attracted considerable attention from both scientific and practical standpoints. Due to their promising characteristics for detecting toxic gases and volatile organic compounds (VOCs) compared with conventional techniques, these devices are expected to play a key role in home and public security, environmental monitoring, chemical quality control, and medicine in the near future. VOCs (e.g., acetone) are blood-borne and found in exhaled human breath as a result of certain diseases or metabolic disorders. Their measurement is considered a promising tool for noninvasive medical diagnosis, for example in diabetic patients. The conventional method for the detection of acetone vapors as a potential biomarker is based on spectrometry. However, the development of MOx-type sensors has made them increasingly attractive from a medical point of view. The objectives of this review are to assess the state of the art of the main MOx-type sensors in the detection of acetone vapors to propose future perspectives and directions that should be carried out to implement this type of sensor in the field of medicine.

1 citations

References
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Journal ArticleDOI
TL;DR: Independent of origin and physiological role, exhaled VOCs are attractive candidates as biomarkers of cellular activity/metabolism, and could be incorporated in future non-invasive clinical testing devices.

155 citations

Journal ArticleDOI
TL;DR: The overall performance of Si-doped WO(3) nanoparticles, made by flame spray pyrolysis, as portable acetone detectors is critically reviewed focusing on the requirements for medical diagnostics.
Abstract: Diabetes is a lifelong condition that may cause death and seriously affects the quality of life of a rapidly growing number of individuals. Acetone is a selective breath marker for diabetes that may contribute to the monitoring of related metabolic disorder and thus simplify the management of this illness. Here, the overall performance of Si-doped WO(3) nanoparticles, made by flame spray pyrolysis, as portable acetone detectors is critically reviewed focusing on the requirements for medical diagnostics. The effect of flow rate, chamber volume and acetone dissociation within the measuring chamber is discussed with respect to the calibration of the sensor response. The challenges for the fabrication of portable breath acetone sensors based on chemo-resistive detectors are underlined indicating possible solutions and novel research directions.

114 citations

Journal ArticleDOI
Jie Zhao1, Li-Hua Huo1, Shan Gao1, Hui Zhao1, Jing-Gui Zhao1 
TL;DR: In this paper, the structure and morphology of SnO2 thin films were analyzed through XRD, UV and AFM methods, and the sensitivity of thin films to methanol, ethanol, propanol and acetone was detected at room temperature.
Abstract: SnO2 thin films were prepared by dip-coating from SnO2 sols of 0.5 and 0.1 mol/l. The structure and morphology of the films were analyzed through XRD, UV and AFM methods. The particles in the films were the standard tetragonal phase of SnO2 with spherical morphology. The average size of SnO2 particles was about 87 nm (0.5 mol/l) and 5 nm (0.1 mol/l), respectively. The UV absorbance of the films increased linearly with increasing the deposition layers. The sensitivity of thin films to methanol, ethanol, propanol and acetone was detected at room temperature, and the effects of concentration of SnO2 sols on the morphology and sensitivity of the films were investigated as well. With decreasing the sol concentration, the grain size of the particles reduced, the gas sensing properties to acetone and ethanol increased. Such films with small size could detect ethanol as low as 2 ppm ethanol. Response and recovery time to methanol, ethanol, propanol and acetone at room temperature were within 30 s and 1 min, respectively.

111 citations

Journal ArticleDOI
23 Jul 2010-Vacuum
TL;DR: In this article, ZnO thin films were prepared by reactive RF sputtering on thermally oxidized Si for gas sensing applications, and three VOC vapors were chosen to investigate the response behavior of the prepared ZnOs.

95 citations

Proceedings ArticleDOI
01 Nov 2010
TL;DR: In this paper, pure and Si-doped WO 3 nanoparticle films are investigated as chemo-resistive acetone detectors for noninvasive diabetes diagnosis by breath analysis.
Abstract: Here, pure and Si-doped WO 3 nanoparticle films are investigated as chemo-resistive acetone detectors. Flame spray pyrolysis was utilized to synthesize and directly deposit the sensitivite nanoparticles on sensor substrates with interdigitated Au electrodes. Doping with Si was used to thermally stabilize the acetone selective ɛ-WO 3 phase at the elevated operating temperatures of metal oxide gas sensors (300 – 500 °C). The effect of static and dynamic testing conditions, such as operating temperature and gas flow-rate, were investigated. Finally, optimal detector operating temperatures are identified, and the feasibility of low acetone detection (ppb) in ideal (dry air) and realistic conditions (90% rh) by these simple Si-doped WO 3 detectors was demonstrated. The utilization of these portable solid state detectors has potential for noninvasive diabetes diagnosis by breath analysis.

33 citations