Your nose is a super sniffing machine which is able to tell the difference between 4000 to 10,000 different odors. Your nose has about one-hundred million receptors that can bind to a particular odor molecule and transmit signals to your brain and your brain tells you what you have smelt.
The electronic nose is a device that detects smell more effectively then the human sense of smell. An electronic nose consists of a mechanism for chemical detection. The electronic nose is an intelligent sensing device that uses an array of gas sensors which are overlapping selectively along with a pattern reorganization component. Nowadays the electronic noses have provided external benefits to a verity of commercial industries, agriculture, biomedical, cosmetics, environmental, food, water and various scientific research fields. The electronic nose detects the hazardous or poisonous gas which is not possible to human sniffers.
The electronic nose was developed in order to mimic human olfaction that functions as a non-separative mechanism: i.e. an odor / flavor is perceived as a global fingerprint. Essentially the instrument consists of head space sampling, sensor array, and pattern recognition modules, to generate signal pattern that are used for characterizing odors.
Electronic noses include three major parts: a sample delivery system, a detection system, a computing system.
This calibration occurs in three stages:
Odor samples from the sources to monitor are collected on site.
The samples are subjected to olfactometric analysis (human panel) to define the odor concentration of the sample.
The electronic noses are exposed to the same samples and their responses are compared with the results of the analysis. The correlation is then established between the two via a statistical non-linear multivariable calculation.
The more commonly used sensors for electronic noses include:
- Metal–oxide–semiconductor (MOSFET) devices – a transistor used for amplifying or switching electronic signals. This works on the principle that molecules entering the sensor area will be charged either positively or negatively, which should have a direct effect on the electric field inside the MOSFET. Thus, introducing each additional charged particle will directly affect the transistor in a unique way, producing a change in the MOSFET signal that can then be interpreted by pattern recognition computer systems. So essentially each detectable molecule will have its own unique signal for a computer system to interpret.
- Conducting polymers – organic polymers that conduct electricity.
- polymer composites – similar in use to conducting polymers but formulated of non-conducting polymers with the addition of conducting material such as carbon black.
- Quartz crystal microbalance – a way of measuring mass per unit area by measuring the change in frequency of a quartz crystal resonator. This can be stored in a database and used for future reference.
- Surface acoustic wave (SAW) – a class of microelectromechanical systems (MEMS) which rely on the modulation of surface acoustic waves to sense a physical phenomenon.
- The Electronic Nose due to its advanced sensing features is being greatly utilized in the various manufacturing Industries.
- It helps in maintaining the quality control and grading, product uniformity and consistency, processing controls, gas leak detection and environmental effluents monitoring.
- It is extensively used in Medical research as well. In chemical Industries such as Food Processing, Cosmetics, and various other manufacturing units.
- It is also used in Volatile Emission assessments, homeland security, environmental protection, biomedical medication, personal safety and product development research.
- The e-nose with its advanced sensor capabilities can extend its applications to various associated fields like agriculture, biomedical, cosmetics, environmental, food, pharmaceutical and various other scientific research fields.
- With its high capabilities, more accurate results, consistency, quality control capabilities and various other facilities are available for the Industrial growth.
- The Electronic nose has brought the revolution in the field of research. It has become a great help for humanitarian growth and making a better working environment by facilitating the better services in less time with the reduction in cost.