A Portable Electrical Impedance Spectroscopy Device for Onion Spoilage Detection Using Polyaniline Coated Impedimetric Paper Sensor

Using the profile of volatile organic compounds (VOCs), onion spoilage is conventionally detected by employing GC-MS. The emission of VOCs in terms of types and concentration is significantly higher in spoiled onions compared to fresh ones. In this work, we propose a low-cost, room-temperature impedimetric sensor to detect spoiled onions. The sensor was fabricated by coating polyaniline (PANI) on the filter paper through polymerization. The impedimetric sensor was validated with an electrical impedance spectroscopy (EIS) instrument and achieved 20% response towards spoiled onions with appreciable repeatability and reproducibility. Further, a portable EIS device was developed that demonstrated a similar response pattern. The results indicate the potential application of the sensor device developed for real-time onion spoilage detection in storehouses.