Abstract
A novel colorless and odorless chemical code system was constructed with gas-phase biosensors
(bio-sniffers). Three volatile chemicals, hydrogen peroxide (H2O2), lactate and choline vapors were used
for chemical code. The bio-sniffer devices for these 3 chemicals were constructed by applying catalase,
lactate oxidase and choline oxidase immobilized membrane to a Clark-type oxygen electrode, respectively.
Each bio-sniffer showed high selectivity for their chemical vapor due to the substrate specificity of the
enzyme without crosstalk error. Thus, a 3-bit (8-channel) chemical code was successfully recognized and
distinguished by 3 kinds of the bio-sniffers.