How to implement a selective colorimetric gas sensor with off the shelf components

Abstract We report on how an inexpensive and very selective gas sensor can be implemented, simply combining colorimetric indicators casted on top of Scotch ® tape, with a commercial microchip adapted here to measure optical reflectance. The system can be easily reproduced (leading to quantitatively consistent results), refreshed and reconfigured to sense different target gases, just replacing the colorimetric tape.