Intelligent gas-sensing systems and their applications

An electronic nose (E-nose) system is a device that strives to sniff complicated gaseous compounds within an aroma, like a human olfactory organ. An E-nose comprises typically of chemical sensors in a large array with associated signal-conditioning and pattern-recognition techniques. It implicates gas-sensing methods of various types using a sensor array that results in partially overlapping sensitivity such that each sensor responds to a range of gases rather than to a specific gas. The selectivity is achievable through analysis of the characteristic pattern obtained from the data responding in the sensor array. An E-nose has several advantages, among which are great benefits for the detection of gases including high-throughput sample detection, small size and moderate cost. For these reasons it has served to solve many and various problems in disparate fields. The objective of this review is to summarize the recent applications of an intelligent gas-sensing system (E-nose), not merely for sensing chemical compounds but also for odor or aroma detection, including the fields of food and beverage industry, medical applications and environmental monitoring.