that is calculated using sinusoidal perturbation on a voltage system. The frequency of the sinusoidal signal is used to calculate the impedance as the real as
well as imaginary components in the electrochemical system. It analyses the
intrinsic material or system property of impedance and hence of very informative for biosensor development and their applications in environmental pollutant detections [56, 57].
• Field effect transistor (FET): It is made up of bridging between two electrodes
made of semiconductor devices and transistor. Electric field inside the channels
are controlled along with their conductivity and charge is drained using third
electrode. When a drain-source voltage is higher than gate-source voltage this
set up functions as a switch conductive or non-conductive states. However when
gate-source voltage gives constant current it acts as an amplifier. The FET
technique hold advantageous for the systems with a weak signal and high
impedance [58, 59].
3 Advantages of Electrochemical Sensors
Application of electrochemical sensors hold many benefits when it comes to
detection of environmental pollutants. Various types of electrochemical sensors can
be used in combination for higher selectivity and specificity as well as robust
technique for the analysis of contaminants present in the solution or the system.
Some of the advantages that these sensors hold may be listed as below [4]:
• Voltammmetric sensors holds additional advantage of higher selectivity and
specificity and hence to probe speciation. Every chemical species such as atoms,
molecules or ions owns a specific oxidation or reduction potential. Such amount
of specificity is lacking in many kinds of detectors.
• Selectivity can be enhanced by proper selection of electrode material such as Ion
selective electrodes. Interferences by other species can also be resolved by
application of certain voltammetric sensors and some electrode materials.
• Electrochemical sensors (especially voltammetric) with controlled potential
prove beneficiary because of high selectivity and low detection limits.
Combinations of potentials can be used in case of analyte accumulation the
surface of electrodes.
• Real time data monitoring and computerized control of the system will be
effective in producing results at a faster pace.
• These sensors are battery operated, easily handling, portable sensing devices
make them useable even at the site of contamination.
• Small size of the sensing devices increases their application at places where
other devices can’t be used.
170
A. Ojha
well as imaginary components in the electrochemical system. It analyses the
intrinsic material or system property of impedance and hence of very informative for biosensor development and their applications in environmental pollutant detections [56, 57].
• Field effect transistor (FET): It is made up of bridging between two electrodes
made of semiconductor devices and transistor. Electric field inside the channels
are controlled along with their conductivity and charge is drained using third
electrode. When a drain-source voltage is higher than gate-source voltage this
set up functions as a switch conductive or non-conductive states. However when
gate-source voltage gives constant current it acts as an amplifier. The FET
technique hold advantageous for the systems with a weak signal and high
impedance [58, 59].
3 Advantages of Electrochemical Sensors
Application of electrochemical sensors hold many benefits when it comes to
detection of environmental pollutants. Various types of electrochemical sensors can
be used in combination for higher selectivity and specificity as well as robust
technique for the analysis of contaminants present in the solution or the system.
Some of the advantages that these sensors hold may be listed as below [4]:
• Voltammmetric sensors holds additional advantage of higher selectivity and
specificity and hence to probe speciation. Every chemical species such as atoms,
molecules or ions owns a specific oxidation or reduction potential. Such amount
of specificity is lacking in many kinds of detectors.
• Selectivity can be enhanced by proper selection of electrode material such as Ion
selective electrodes. Interferences by other species can also be resolved by
application of certain voltammetric sensors and some electrode materials.
• Electrochemical sensors (especially voltammetric) with controlled potential
prove beneficiary because of high selectivity and low detection limits.
Combinations of potentials can be used in case of analyte accumulation the
surface of electrodes.
• Real time data monitoring and computerized control of the system will be
effective in producing results at a faster pace.
• These sensors are battery operated, easily handling, portable sensing devices
make them useable even at the site of contamination.
• Small size of the sensing devices increases their application at places where
other devices can’t be used.
170
A. Ojha