# Advancements and Prospects of Electronic Nose in Various Applications: A Comprehensive Review
## 2 E-Nose System  
### Historical Evolution of Sensory Technologies  
The inception of odor examination tools dates back to 1954, when [PERSON] introduced a pivotal advancement--a microelectrode featuring a platinum wire connected to a millivoltmeter [43]. This innovation paved the way for subsequent developments. A few years later, [PERSON] unveiled a mechanical olfactory system, laying the groundwork for discriminating between both simple and intricate aromas [44; 45]. The pursuit of replicating the complexities of the human olfactory system led to remarkable breakthroughs. In 1982, [PERSON] and [PERSON] achieved a significant milestone at Warwick University by unveiling the first intelligent model of an artificial nose [44]. Comprising three metal oxide sensors, this innovation displayed the remarkable capability to identify up to 20 distinct odorants. Following this, [PERSON] and [PERSON] introduced an integrated sensor, equipped with six diverse metal oxide semiconductors, which demonstrated the ability to identify and quantify stents [46]. These strides marked significant progress in emulating the intricate human olfactory system [20; 47]. In a pivotal moment in 1988, [PERSON] and [PERSON] introduced the term \"electronic nose,\" drawing a parallel to the biological sense of smell. This terminology has since gained widespread recognition, underscoring the essence of the technology [1]. Notably, the electronic nose (e-nose) system consists of several essential components: a sampling system for handling and storing samples during analysis, a sensor array to capture signals resulting from interactions between sensing materials and volatile compounds, and a computer responsible for data storage, pre-processing, and processing [48; 49; 50], as illustrated in Figure 1. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Title of the Review** & **Focus** & **Content** & **Year** & **Ref** \\ \hline \multirow{8}{*}{[PERSON], [PERSON] et al.:Electronic Nose and its Application in the Food Industry: A Review} & Exploration of e-nose use in food industry & The review explores the significance of food testing technology, focusing on the electronic nose (e-nose) as an efficient, fast, and non-destructive tool in the food industry. It covers the basic principle and components of the e-nose, including gas sensor selection, sampling methods, and data processing. This review discusses various applications of e-noses in the food industry, such as freshness assessment, process monitoring, flavor evaluation, authenticity verification, quality control, origin traceability, and pesticide residue detection. Finally, it addresses current challenges and suggests future research directions in the field. & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: _Cont._  
Figure 1: Schematic illustration of the biological olfactory system (**A**) and e-nose technology (**B**) [50]. The 1990s witnessed the commercialization of electronic noses, with the advent of offerings by pioneers like AlphaMOS (1993), followed by Neotronics and Aromascan (1994). The burgeoning potential of applications propelled the growth of the electronic nose systems market, leading to the development of a diverse array of devices utilizing various sensing technologies. While several companies currently serve the market, it is worth noting that certain e-nose systems, previously prominent in the literature, are no longer available [51]. Building upon the triumphs of electronic noses, the journey expanded toward crafting devices capable of mimicking the human gustatory system. In 1985, [PERSON] and [PERSON] took a significant step by unveiling a system designed for analyzing liquid samples. This pioneering system hinged on a sensor array, marking a novel approach in taste detection technology [52]. Furthermore, the historical progression of e-nose technology has seen an exploration of novel applications beyond traditional odor analysis.