Metal Oxide Semiconductor-based gas sensor for Acetone sensing
01 Nov 2018-
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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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
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
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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TL;DR: In this paper, the authors extensively review recent developments in this field, focusing the attention on the detection of some common VOCs, including acetone (C3H6O), acetylene (C2H2), benzene (C6H6), cyclohexene (Cyclohexenene) and 2-propanol (C7H8O), by means of conductometric solid state sensors based on nanostructured semiconducting metal oxides.
777 citations
Additional excerpts
...[6] O2 (g ) + ne- ⇔ Oxn- (ad ) + holen+ (1) CH3COCH3 (g) + Oxn- (ad) ⇔ CH3COCH3-O + ne- (2) This change in resistance is related to the concentration of the target gas....
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TL;DR: Novel chemo-resistive detectors have been developed that allow rapid measurement of ultralow acetone concentrations with high signal-to-noise ratio in ideal and realistic conditions and may offer a portable and cost-effective alternative to more bulky systems for noninvasive diabetes detection by human breath analysis.
Abstract: Acetone in the human breath is an important marker for noninvasive diagnosis of diabetes. Here, novel chemo-resistive detectors have been developed that allow rapid measurement of ultralow acetone concentrations (down to 20 ppb) with high signal-to-noise ratio in ideal (dry air) and realistic (up to 90% RH) conditions. The detector films consist of (highly sensitive) pure and Si-doped WO3 nanoparticles (10−13 nm in diameter) made in the gas phase and directly deposited onto interdigitated electrodes. Their sensing properties (selectivity, limit of detection, response, and recovery times) have been investigated as a function of operating temperature (325−500 °C), relative humidity (RH), and interfering analyte (ethanol or water vapor) concentration. It was found that Si-doping increases and stabilizes the acetone-selective e-WO3 phase while increasing its thermal stability and, thus, results in superior sensing performance with an optimum at about 10 mol % Si content. Furthermore, increasing the operation ...
546 citations
413 citations
"Metal Oxide Semiconductor-based gas..." refers background in this paper
...Breath analysis has advantages over other methods because breath is a less complex mixture in comparison to urine and blood, sample collection is an easy task [1]....
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TL;DR: The results from the six independent studies using clearly-defined Type 1 and Type 2 diabetic patients unanimously support that an elevated mean breath acetone concentration exists in Type 1 diabetes.
Abstract: Since the ancient discovery of the 'sweet odor' in human breath gas, pursuits of the breath analysis-based disease diagnostics have never stopped. Actually, the 'smell' of the breath, as one of three key disease diagnostic techniques, has been used in Eastern-Medicine for more than three thousand years. With advancement of measuring technologies in sensitivity and selectivity, more specific breath gas species have been identified and established as a biomarker of a particular disease. Acetone is one of the breath gases and its concentration in exhaled breath can now be determined with high accuracy using various techniques and methods. With the worldwide prevalence of diabetes that is typically diagnosed through blood testing, human desire to achieve non-blood based diabetic diagnostics and monitoring has never been quenched. Questions, such as is breath acetone a biomarker of diabetes and how is the breath acetone related to the blood glucose (BG) level (the golden criterion currently used in clinic for diabetes diagnostic, monitoring, and management), remain to be answered. A majority of current research efforts in breath acetone measurements and its technology developments focus on addressing the first question. The effort to tackle the second question has begun recently. The earliest breath acetone measurement in clearly defined diabetic patients was reported more than 60 years ago. For more than a half-century, as reviewed in this paper, there have been more than 41 independent studies of breath acetone using various techniques and methods, and more than 3211 human subjects, including 1581 healthy people, 242 Type 1 diabetic patients, 384 Type 2 diabetic patients, 174 unspecified diabetic patients, and 830 non-diabetic patients or healthy subjects who are under various physiological conditions, have been used in the studies. The results of the breath acetone measurements collected in this review support that many conditions might cause changes to breath acetone concentrations; however, the results from the six independent studies using clearly-defined Type 1 and Type 2 diabetic patients unanimously support that an elevated mean breath acetone concentration exists in Type 1 diabetes. Note that there is some overlap between the ranges of breath acetone concentration in individual T1D patients and healthy subjects; this reminds one to be careful when using an acetone breath test on T1D diagnostics. Comparatively, it is too early to draw a general conclusion on the relationship between a breath acetone level and a BG level from the very limited data in the literature.
215 citations
TL;DR: Nanostructured anatase TiO2 was produced by flame spray pyrolysis (FSP) and tested for sensing of volatile organic compounds and CO at 500°C as mentioned in this paper.
Abstract: Nanostructured anatase TiO2 was produced by flame spray pyrolysis (FSP) and tested for sensing of volatile organic compounds and CO at 500 °C. The as-prepared powders were characterized by transmission/scanning electron microscopy, X-ray diffraction and nitrogen adsorption. Titania films about 30 μm thick on alumina substrates interdigitated with gold electrodes were prepared by drop-coating a heptanol suspension of these powders. The films showed a high signal of n-type sensor to isoprene, acetone and ethanol at concentrations ranging from 1 to 75 ppm in dry N2/O2 at 500 °C. The response (within seconds) and recovery (within minutes) times were very fast. Heat-treatment at 900 °C caused a nearly complete anatase to rutile transformation and a transition to p-type sensing behavior. That resulted in a poor sensor signal to all hydrocarbons tested and considerably longer recovery times than that of the anatase sensor. That rutile sensor could detect CO that the original, anatase sensor could not. For ethanol the sensor response changed back to n-type.
174 citations
"Metal Oxide Semiconductor-based gas..." refers background in this paper
...Tin Oxide (SnO2) [7], Titanium Oxide (TiO2) [8], Zinc Oxide (ZnO) [9] are other possible thin films that can be used for Acetone sensing....
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