SENSORS |
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Electrochemical sensors can monitor target analytes online, eliminating chain-of-custody concerns associated with off-line analysis. These sensors are small, rugged and often extremely selective. Guelph scientists are working in several programs to develop new electrochemical sensors.
Proprietary suppressed-type electrochemical detection systems have been developed at Guelph. Awarded U.S. patents, these systems can detect water inorganic media at the ppb level and water-borne benzene in the low ppm regime. Unlike capactivie-type sensors, the hydrophilic small pore zeolite used in these sytems sufers no inteferences from polar organics even at concentrations of several percent.
Metal Oxides Development of gas sensors is important not only for air pollution control but for improving the efficiency of automobile engines. Metal oxides have found application because their large band gap makes undoped materials highly resistive. Consequently, their conductivity is highly sensitive to the number and nature of adsorbed gas molecules on the surface and at grain boundaries. For effective sensing, the metal oxide must be porous. Centre researchers are studying a variety of metal oxide films that are highly resistive and porous. They plan to develop new preparation methods and design new oxides that will be more sensitive and selective.
Biosensors
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Zeolites
Researchers
produce biosensors and chemical sensors by attaching thin organic
films to conductive electrodes. They make these films respond
selectively to particular species through molecular engineering,
by incorporating either specifially designed or biological catalytic
reagents, such as enzymes or antibodies. These thin organic films
are designed for many functions. For example, one component of
the membrane excludes interfering species, while another may serve
to bind or concentrate the analyte before its detection.
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