SANIKA JOSHI(200601017 ) What is e-nose and e-tongue? An electronic - - PowerPoint PPT Presentation

Team F TANU JINDAL(200601014) SANIKA JOSHI(200601017)

What is e-nose and e-tongue?

 An electronic nose (e-nose) is a device that identifies

the specific components of an odor and analyzes its chemical makeup to identify it.

 The electronic tongue (e-tongue) is an instrument that

measures and compares tastes.

 These can be used for a wide range of applications

including quality control, product matching, origin identification, spoilage detection and flavor quantification.

General Working of E-sensors

Similarity with human tongue

 E-tongue is structurally similar to the human tongue, which has

different kinds of receptors that respond to distinct tastes.

 Like human receptors, each sensor has a spectrum of reactions

different from the other.

 In the biological mechanism, taste signals are transmitted by

nerves in the brain into electric signals. Similarly,e-tongue sensors process generate electric signals as potentiometric variations.

 Taste quality perception and recognition is based on building or

recognition of activated sensory nerve patterns by the brain and

• n the taste fingerprint of the product. This step is achieved by

the e-tongue’s statistical software which interprets the sensor data into taste pattern

Working of E-Tongue(1)

 The e-tongue is based on an array of tiny synthetic

membranes built on a single silicon chip called a multisensor.

 Liquid and solid samples are analyzed differently.  A potentiometric difference between each sensor and a

reference electrode is measured and recorded by the E-Tongue software.

 The information given by each sensor is

complementary and the combination of all sensors results generates a unique fingerprint.

Working of E-Tongue(2)

A completely different idea for an electronic tongue realization was presented in 1997

 In this method 10 to 100 polymer micro-beads are

positioned on a silicon chip of about one centimeter square.

 Beads are arranged in tiny pits to represent taste buds

and each pit is marked with dye to create a red, green, and blue (RGB) color bar.

 The colors change when chemicals are introduced to

the e-tongue.

Array of tiny pits

Working of E-Tongue(3)

 Simple RGB analysis is performed by a camera on a

chip connected to a computer. NOTE :

 E-tongue can detect an electronic change of 10 part per

billion

Applications

Electronic Tongues has several applications in various industrial areas: the pharmaceutical industry, food and beverage sector. It can be used to:

 Analyze flavor ageing in beverages  Quantify bitterness or “spicy level” of drinks or

dissolved compounds

 Analyze medicines stability in terms of taste

Comparison with human nose

Functional Blocks

It primarily consists of four functional blocks,

 Odour Handling and Delivery System  Sensors and Interface Electronics  Signal Processing  Intelligent Pattern Analysis and Recognition.

Details of working (1)

 Odour handling and delivery system ensures constant

exposure rate of volatile odour vapour to sensor array chamber.

 Discrimination among complex odours is done using

array of sensors which consists of a number of broadly tuned sensors that are treated with a variety of odour- sensitive biological or chemical materials.

Details of working (2)

 The chemical sensors (Metal Oxide Sensors) are a set

• f electrodes which are coated with different polymer

films that are specially designed to conduct electricity .

 Because each film is made of a different polymer, each

• ne reacts in a slightly different way upon contact with

different volatile chemical compounds.

Each polymer changes its size, and therefore its resistance, by a different amount, making a pattern of the change .

Details of working (3)

 The response signals of sensor array are conditioned

and processed through suitable circuitry and fed to an intelligent pattern recognition engine for classification, analysis and declaration.

Applications of E-Nose

 Used for quality control applications in the food,

beverage and cosmetics industries.

 Detection of odors specific to diseases for medical

diagnosis

 Detection of pollutants and gas leaks for

environmental protection.

 Water and wastewater analysis.

Problems Faced

 The machines are large and expensive  Have limited sensitivity  Frequent need of re-calibration

Therefore current research is focused on making the devices smaller, less expensive, and more sensitive.

Conclusion

 Excellent tools for sensory measurements.  Both quantitative and qualitative results can be

• btained.

 Detection thresholds are similar or better than those of

human receptors.

 Simplicity , objectivity and speed of analyses make E-

sensors very advantageous.

References

 Alpha-MOS_Articles_0308_Soft_Drinks.pdf  Alpha-MOS_Articles_0310_AAPS.pdf  Artificial electronic tongue in comparison to the

electronic nose - state of the art and trends [Peter Hauptmann, Ralf Borngraeber, Jens Schroeder, Otto- von-Guericke-University]