Electronic Nose (E-Nose) instruments analyze odors and volatile compounds (VOC). In a way similar to human nose, Electronic Noses (E-Noses) allow global analysis of the headspace (volatile compounds) generated by liquid, gaseous or solid samples. Usually Electronic-Nose odor analyzers consist of three main parts: a sampling system, a detection system, a data acquisition and processing system. Different detection technologies used for odor sensing and analysis are: Gas sensors (Metal Oxide Sensors or MOS), Ultra Fast Gas Chromatography, Fingerprint Mass Spectrometry, and Soft Ionized Mass Spectrometry. Electronic Nose (ENose) is designed as an event or incident monitor to provide rapid, early identification and quantification of changes in the atmosphere caused by leaks or spills of analytes (chemical species) to which it has been trained.

Working Principle of Electronic Nose

Most existing chemical sensors are designed to detect specific molecules. Array-based sensing uses non-specific sensors in which the pattern and magnitude of response are used to identify and quantify the presence of contaminants. Array-based sensors are based on a biological model of “sniffing”, detecting changes in odor, and can be trained to detect new patterns. With an electronic nose, a baseline of clean air is established, and deviations from that baseline are recorded as changes in resistance of the sensors. The pattern of distributed response of the sensors may be deconvoluted, and contaminants identified and quantified by using a software analysis program such as pattern recognition and/or neural network.

Depends on the design complexity, For some things, the ENose is more sensitive than the human nose; for some things it is not. That depends on the group of sensors that have been selected for the array. In addition, the ENose can detect some things that humans and other mammals cannot, such as mercury.

An electronic nose is an array of non-specific chemical sensors, controlled and analyzed electronically, which mimics the action of the mammalian nose by recognizing patterns of response to vapors. The sensors used here are conductometric chemical sensors which change resistance when exposed to vapors. The sensors are not specific to any one vapor; it is in the use of an array of sensors, each with a different sensing medium, that gases and gas mixtures can be identified by the pattern of response of the array. Electronic Noses have been discussed by several authors, and may be applied to environmental monitoring and quality control in such wide fields as food processing, and industrial environmental monitoring, R&D, formulation, product development, process monitoring and quality control applications.