Colorimetric method for odor discrimination using dye-coated plate and multiLED sensor

Simple colorimetric method for odor discrimination is described. A dye-coated plate is illuminated with various LEDs of different colors and then the reflected light is detected. The color of the plate changes when the dye coating is exposed to odors. Pattern recognition of multiLED sensor outputs makes it possible to discriminate among odors. Bad smells such as triethylamine, alcohol, acetic acid and acetaldehyde are discriminated using this sensor. The dyes used (metal porphine, Nile Red and Methyl Red) were tested and their different characteristics were obtained. Thus, multiple dyes in addition to multiple LEDs might enhance the reliability of the discrimination.