Abstract: A device for detecting the presence of a chemical material, such as a gas, amongst a number of incident chemical materials comprises a group of sensors having overlapping broadband selectivities in respect of the incident materials, so that each sensor responds, to a greater or smaller extent, to each of the materials. The sensor outputs are fed to a signal processor which produces, for each material, a notional vector. These vectors are compared with stored reference vectors to identify the material under investigation. The responses to the various materials have a time-varying portion and a portion of constant value. Certain materials may produce the same constant value, but different time-varying portions. The latter portions are therefore also taken into account in identifying the materials. A chromatographic layer may be provided over the sensors to distinguish between chemical species in the materials under test.

Abstract: A sensor device for the analysis of a sample fluid comprises a substrate in a surface of which an elongate channel is micromachined. The channel contains a material, such as a starch, agarose, alginate, carrageenin or polyacrylic polymer gel, with a biological material for causing separation of the sample fluid as the fluid passes along the channel. The biological material may comprise, for example, a binding protein, an antibody, a lectin, an enzyme, a sequence of enzymes or a lipid. Pairs of sensing electrodes are spaced apart along the walls of the channel. The device may be used, for example, for testing blood samples.