Carbon monoxide is one of the most important reducing gases to be detected in combustion of hydrocarbon fuels, petroleum and automobile industries, heat-treating furnaces and, also in the first stages of fire. During the past four decades, gas sensors based either on the surface characteristics or the bulk properties of ceramics have been the subject of extensive research and development. New m...

The complexity of the odours issue arises from the sensory nature of smell. From the evolutionary point of view olfaction is one of the oldest senses, allowing for seeking food, recognizing danger or communication: human olfaction is a protective sense as it allows the detection of potential illnesses or infections by taking into account the odour pleasantness/unpleasantness. Odours are mixture...

Reliable detection of hazardous materials is a fundamental requirement of any national security program. Such materials can take a wide range of forms including metals, radioisotopes, volatile organic compounds, and biological contaminants. In particular, detection of hazardous materials in highly challenging conditions — such as in cluttered ambient environments, where complex collections of a...

We report the development of useful chemical sensors from chemically converted graphene dispersions using spin coating to create single-layer films on interdigitated electrode arrays. Dispersions of graphene in anhydrous hydrazine are formed from graphite oxide. Preliminary results are presented on the detection of NO(2), NH(3), and 2,4-dinitrotoluene using this simple and scalable fabrication ...

A new type of chemical sensor to detect explosive related compounds has been designed and fabricated with an organic photovoltaic cell as the active element. The detection of chemical molecules is performed by optically exciting the cell while its photovoltaic open-circuit voltage is continuously sampled. Upon exposure to compounds like nitroaromatics, the sensors exhibit a significant increase...

This chapter is concerned with the design and operation of devices for the measurement of chemical concentrations in living systems. Whilst the meaning of chemical sensors has been somewhat broadened in recent years, a useful definition from a recent authoritative review [1] is: “chemical sensors are miniaturised analytical devices that can deliver real time and online information on the presen...

[Bio]chemical sensors, defined as devices which convert a chemical state into an electrical signal [1], have been the subject of a strong development during the past few decades. A sensor has essentially two parts (Fig. 1): a detecting element, in which the presence of an external stimulus produces a change of some property (optical, mechanical, electrical ...), and a transducing element, which...

Comprehensive identification of chemical contaminants in Army field water supplies can be a lengthy process, but rapid analytical methods suitable for field use are limited. A complementary approach is to directly measure toxicity instead of individual chemical constituents. Ten toxicity sensors utilizing enzymes, bacteria, or vertebrate cells were tested to determine the minimum number of sens...

We have developed a new chemical sensor array by combining polymer-based chemiresistors with a standard integrated circuit technology. We fabricated an array of addressable chemical sensor sites in a CMOS process, and then performed a post-processing step of electroless gold to create sensor contacts. We create sensors by spraying a mixture of nonconductive polymers and carbon black particles o...