Chemical sensing technology is now employed in a wide variety of disciplines, ranging from electrochemical analysis, through biomedical measurement, to pollution monitoring and industrial control.
Chemical sensors have many applications in pollution monitoring and detection of contaminants. They are used to measure carbon monoxide levels in underground car parks and in steel plants, to detect gas build-ups in homes and coal mines, to find ammonia in frozen food and for many other applications. The pressure of legislation concerning environmental issues and public awareness of the problems makes chemical sensing of pollutants increasingly important.
Solid-state gas sensors work by measuring a physical property changed by a reaction at the surface. Solid electrolytes used in chemical sensors measure electrical conductivity changes. Catalytic sensors, such as the pellistor, measure temperature changes due to heat of reaction at the surface. Many solid-state electronic devices are used in sensors. Integrated circuits such as CMOS and thick film devices, FETs, ISFETs, MIS and MOS systems are used as the basis of sensors, as are optical fibres and surface acoustic wave devices.
Biosensors contain a part which has a biological origin, such as an enzyme or an antibody. The biological component is in contact with a suitable physical transducer which converts the biological signal into an electrical one. Applications for biosensors are in health care, the bioprocessing industry and environmental monitoring.
The increasing importance of chemical sensing technology is reflected in the Inspec Database, which provides extensive coverage of this rapidly expanding field. In Section A (Physics Abstracts), the following parts of the classification scheme contain relevant information: