Sensor Used in E-nose - The Electronic Nose Artificial Olfaction Technology - page 174

Table 6.4 Summary of advantages and disadvantages of E-nose sensor types [ 18 ]
Sensor type Advantages Disadvantages

Calorimetric or
catalytic bead
(CB)

Fast response and recovery time, high specificity for oxidized
compounds

High temperature operation, only sensitive to oxygen containing
compounds

Catalytic field
effect Sensors
(MOSFET)

Small sensor size, inexpensive operating costs Requires environmental control, baseline drift, low sensitivity to

ammonia and carbon dioxide

Conducting
polymer sensors

Ambient temperature operation, sensitive to many VOCs, short
response time, diverse sensor coatings, inexpensive, resistance
to sensor poisoning

Sensitive to humidity and temperature, sensors can be overloaded
by certain analytes, sensor life is limited

Electrochemical
sensors (EC)

Ambient temperature operation, low power consumption, very
sensitive to diverse VOCs

Bulky size, limited sensitivity to simple or low mol. wt. gases

Metal oxides
semiconducting
(MOS)

Very high sensitivity, limited sensing range, rapid response and
recovery times for low mol. wt. compounds (not high)

High temperature operation, high power consumption, sulfur and
weak acid poisoning, limited sensor coatings, sensitive to
humidity, poor precision

Optical sensors Very high sensitivity, capable of identifications of individual

compounds in mixtures, multiparameter detection capabilities

Complex sensor array systems, more expensive to operate, low
portability due to delicate optics and electrical components

Quartz crystal
microbalance
(QMB)

Good precision, diverse range of sensor coatings, high sensitivity Complex circuitry, poor signal-to-noise ratio, sensitive to humidity

and temperature

Surface acoustic
wave (SAW)

High sensitivity, good Response time, diverse sensor coatings,
small, inexpensive, sensitive to virtually all gases

Complex circuitry, temperature sensitive, specificity to analyte
groups affected by polymeric- film sensor coating

MPEN One for all, no application specific design, fast response, excellent

sensitivity, higher stability-small size, disposable, good
accuracy

Complex system, Higher initial cost