Conducting polymer coated filter paper based disposable electronic tongue

A disposable filter paper based electronic tongue using different conducting polymers is developed in this work. Sensors were prepared using Whatman filter papers of dimensions 6 mm × 5 mm coated with different conducting polymers (polyaniline and polypyrrole, both in doped and de-doped form). Two Ag electrodes were deposited with a separation of 4 mm for AC impedance spectroscopic measurements in the frequency range of 10 Hz – 10 kHz with a 100 mV excitation voltage. The developed sensor was subjected to different concentrations of four basic tastants i.e., salty, sweet, sour and umami. The sensitivity of the sensor was found to be better than the human tongue for all the different tastants. The sensors were also used to differentiate between different water samples and fruit juices, with a promising potential for use in food quality monitoring. Use of principal component analysis on the impedance data aided in formation of clusters, thus distinguishing different types of water samples.