An electronic nose for amine detection based on polymer/SWNT-COOH nanocomposites

An electronic nose (e-nose) system based on polymer/carboxylic-functionalized single-walled carbon nanotubes (SWNTs-COOH) was developed for sensing various volatile amines such as dimethylamine, dipropylamine, pyridine, and ammonia solution. The SWNTs-COOH were dispersed in the matrix of different polymers; polyvinyl chloride (PVC), cumene terminated polystyrene-co-maleic anhydride (cumene-PSMA), poly(styrene-co-maleic acid) partial isobutyl/methyl mixed ester (PSE), and polyvinylpyrrolidon (PVP). These composites were dropped on interdigitated gold electrodes to make the gas sensors. The response of these sensors to volatile amines was studied by both static and dynamic flow measurement. By using a simple pattern recognition based on the principle component analysis (PCA), the volatile amines can be discriminated. This e-nose will be useful for monitoring the freshness of foods and farm air quality.