19-04-2012, 02:53 PM
ELECTRONIC NOSE
rakesh.pptx (Size: 2.23 MB / Downloads: 42)
INTRODUCTION
The electronic nose was developed in order to mimic human olfaction that functions as a non-separate mechanism: i.e. an odor 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.
This electronic nose is the first to be validated by the US EPA with both volatiles as well as semi-volatile organic compounds.
WORKING PRINCIPLE
The sample delivery system enables the generation of the headspace of a sample,
which is the fraction analyzed. The system then injects this headspace into the
detection system of the electronic nose.
The 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. Each sensor is sensitive
to all volatile molecules but each in their specific way.
The computing system works to combine the responses of all of the sensors,
which represents the input for the data treatment. This part of the instrument
performs global fingerprint analysis and provides results and representations that
can be easily interpreted.
Advantages
Compact Device
High Portability
High Reliability
High Versatility
Wide Application
Disadvantages
High Cost
Time Delay Between Successive Tests
Insensitivity To Some Species
rakesh.pptx (Size: 2.23 MB / Downloads: 42)
INTRODUCTION
The electronic nose was developed in order to mimic human olfaction that functions as a non-separate mechanism: i.e. an odor 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.
This electronic nose is the first to be validated by the US EPA with both volatiles as well as semi-volatile organic compounds.
WORKING PRINCIPLE
The sample delivery system enables the generation of the headspace of a sample,
which is the fraction analyzed. The system then injects this headspace into the
detection system of the electronic nose.
The 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. Each sensor is sensitive
to all volatile molecules but each in their specific way.
The computing system works to combine the responses of all of the sensors,
which represents the input for the data treatment. This part of the instrument
performs global fingerprint analysis and provides results and representations that
can be easily interpreted.
Advantages
Compact Device
High Portability
High Reliability
High Versatility
Wide Application
Disadvantages
High Cost
Time Delay Between Successive Tests
Insensitivity To Some Species