Electronic Nose: Current Status and Future Trends

Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 15, Tübingen, Germany.
Chemical Reviews (Impact Factor: 46.57). 03/2008; 108(2):705-25. DOI: 10.1021/cr068121q
Source: PubMed


The development of the electronic nose have paved the way for the classification of bacteria, to monitor air quality on the space shuttle, or to check the spoilage of foodstuff. However, the electronic nose still is unable to discriminated between flavors, perfumes, smells and as a replacement for the human nose. Although it has been used to detect some important nonodorant gases, it is not adapted to substances of daily importance in mammalian life such as the scent of other animals, foodstuff or spoilage. Due to such limitations, the electronic nose was developed to mimic the human nose. It turns out that the human nose's unequaled performance is not due to the high number of different human receptor cells, but their selectivity and their unsurpassed sensitivity for some analyte gases. As such, the success of the electronic nose will not rely on increasing the number of individual sensors and creating redundant information by adding more similar sensors, but rather on DNA, molecular, imprinted molecules or even mobilized natural receptors, which promise to increase the sensitivity and importantly selectivity. An increase in the sensitivity can be achieved by appropriate sample pretreatment and preconcentration techniques, whereas filters and separation units can be used to increase the selectivity and reduce interfering substances.

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    • "These sensors based upon selective material properties can provide fast response times that enable on-line measurements [11]. Electronic noses (e-noses) are already deployed in different fields such as food processing, perfumes, chemical industry and the environment [14]. With respect to medical diagnostics, sensor arrays have already shown promising results in the fields of renal disease, lung cancer and diabetes detection [15] [16]. "
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    ABSTRACT: Breath analysis has the potential to detect and monitor diseases as well as to reduce the corresponding medical costs while improving the quality of a patient's life. Herein, a portable prototype, consisting of a commercial breath sampler modified to work as a platform for solid-state gas sensors was developed. The sensor is placed close to the mouth (<10 cm) and minimizes the mouth-to-sensor path to avoid contamination and dilution of the target breath marker. Additionally with an appropriate cooling concept, even high sensor operating temperatures (e.g. 350 °C) could be used. Controlled sampling is crucial for accurate repeatable analysis of the human breath and these concerns have been addressed by this novel prototype. The device helps a subject control their exhaled flow rate which increases reproducibility of intra-subject breath samples. The operation of this flame-made selective chemo-resistive gas sensor is demonstrated by the detection of breath acetone.
    Journal of Breath Research 10/2015; 9(4):047101. DOI:10.1088/1752-7155/9/4/047101 · 4.63 Impact Factor
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    • "c o m / l o c a t e / c a r b o n and desorption of molecules [5]. In addition, irreplaceable advantages of graphene-based sensors, such as easy integration into existing technologies, high transparency, excellent flexibility, and considerable stretchability, make them highly attractive candidates for applications in flexible electronics, the next-generation ubiquitous platform [6] [7] [8] [9] [10]. "
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    ABSTRACT: Reduced graphene oxide (rGO) is one of the promising sensing elements for high-performance chemoresistive sensors because of its remarkable advantages such as high surface-to-volume ratio, outstanding transparency, and flexibility. In addition, the defects on the surface of rGO, including oxygen functional groups, can act as active sites for interaction with gaseous molecules. However, the major drawback of rGO-based sensors is the extremely sluggish and irreversible recovery to the initial state after a sensing event, which makes them incapable of producing repeatable and reliable sensing signals. Here, we show that pristine GO can be used as the active sensing material with reversible and high response to NO2 at room temperature. First-principles calculations, in conjunction with experimental results, reveal the critical role of hydroxyl groups rather than epoxy groups in changing metallic graphene to the semiconducting GO. We show that the adaptive motions of the hydroxyl groups, that is, the rotation of these groups for the adsorption of NO2 molecules and relaxation to the original states during the desorption of NO2 molecules, are responsible for the fast and reversible NO2 sensing behavior of GO. Our work paves the way for realizing high-response, reversible graphene-based room-temperature chemoresistive sensors for further functional convergence.
    Carbon 09/2015; 91:178-187. DOI:10.1016/j.carbon.2015.04.082 · 6.20 Impact Factor
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    • "Compared to them, electronic nose (E-nose) is a simple, rapid, and noninvasive technology that require less sample and no organic reagents. The initial and unique chemical form of the volatile components in CHM could be reflected by their response to E-nose, which can be used to identify different CHM [7]. E-nose, which has already been applied in various fields in recent decades, is a very promising method for identifying different samples based on their different volatile components . "

    Journal of Food and Drug Analysis 08/2015; DOI:10.1016/j.jfda.2015.07.001 · 0.62 Impact Factor
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