A Presentation onELECTRONIC NOSE By:- Naveen Sihag B.Tech
IntroductionAn electronic nose is a device intended to detectodors or flavours.Over the last decades, “electronic sensing” or “e-sensing” technologies have undergone importantdevelopment from a technical and commercial point ofview.Since 1992, researches have been conducted todevelop technologies, commonly referred to aselectronic nose that could detect and recognise odorsand flavours.
Contents E-sensing Techniques to analyze odors. Working Principle of Electronic Nose. How to perform an analysis. A range of applications. References.
What is e-sensing ?“Electronic Sensing” refers to the capability of reproducing human senses using sensor arrays and pattern recognition systems.
Techniques to analyze odorsIn industry, aroma assessment is usuallyperformed by gas chromatography. Thetechnique gives information about volatileorganic compounds but the correlation betweenanalytical results and actual odor perception isnot direct due to potential interactions betweenseveral odorous components.
The three major parts of electronic noseA sample delivery system. A detection system. A computing system.
A sample delivery systemThe sample delivery system enables thegeneration of the headspace (volatilecompounds) of a sample, which is the fractionanalyzed. The system then injects thisheadspace into the detection system of theelectronic nose.The sample delivery system is essential toguarantee constant operating conditions.
The detection systemThe detection system, which consists of a sensor set, is the “reactive” part of the instrument. When in contact with volatile compounds, the sensors react, which means they experience a change of electrical properties.
The sensors The most commonly used sensors are:-• MOS (Metal Oxide Semiconductors).• CP (Conducting Polymers).• MOSFET ( Metal Oxide Semiconductor Field Effect Transistor).
MosA metal oxide semiconductor structure is obtained by depositing a layer of silicon dioxide (SiO2) and a layer of metal on top of a semiconductor die. As the silicon dioxide is a dielectric material its structure is equivalent to a planar capacitor, with one of the electrode replace by a semiconductor.
What is “MOSFET” ?It stand for metal oxide semiconductor field-effect transistor. It is an important semiconductor device and is widely employed in many circuit application.
How to perform an analysisAn electronic nose needs to be trained withqualified samples so as to build a databaseof reference. Then the instrument can recognizenew samples by comparing volatile compoundsfingerprint to those contained in its database,performing qualitative or quantitative analysis.
The applications The electronic nose instruments are used:-1. In Research and Development laboratories.2. In Quality Control laboratories.3. Process and Production department.
In Research and Development laboratories:- In the research & development laboratories, the electronic nose are used for:- 1. The formulation or reformulation of products. 2. Self life and stability studies. 3. Selection of raw materials. 4. Packaging interaction effects. and so on..
In Quality Control labs. In quality control laboratories, electronic nose are used for :-1. Conformity of raw materials, intermediate and final products.2. Batch to batch consistency.3. Detection of contamination, spoilage, adulteration.4. Monitoring of storage conditions. and so on..
In Process and Production department In process and production department, electronic nose is used for :-1. Managing raw material variability.2. Comparison with a reference product. and so on..