A Fast-Response Odor Detector for Food Analysis

挥发性有机化合物（VOCs）是一大类有机化学物质，在常温常压条件下极易蒸发。挥发性有机化合物从各种各样的自然和人为来源排放到大气中。从生物医学诊断、国土安全、食品安全和质量到环境保护，对不同来源排放的挥发性有机化合物的表征和监测非常重要。该提案旨在开发一种基于电子鼻原理的新型现场实时气味传感器。本研究的结果将对降低成本、提高可移植性、提高当前VOC检测方法的分析速度和分辨率产生重大影响。该装置将结合微技术、化学和统计学开发，并将用于高分辨率检测食品掺假，这是一个严重而普遍的全球问题。这项研究在为社会需求推进科学和技术的同时，将为学生提供宝贵的经验，因为他们将在跨学科的环境中接受培训。此外，拓展活动将教育大学预科学生如何将先进的科学和工程结合起来解决现实的、当前的问题。提出的研究目标是通过将电子鼻和快速气相色谱（GC）中的重要概念合并到一个小的足迹中来开发快速气味检测器。该系统的重点是具有多个毛细管并行工作的独特设计的色谱芯片。该芯片将使用微机电系统（MEMS）技术在硅中制造，并将使用离子液体进行功能化。主要的加工步骤包括深度反应离子蚀刻，然后是硅-玻璃阳极键合。所提出的色谱芯片将与检测器或多个检测器连接，以产生样品的快速气味指纹。输出将是一系列色谱反应，将使用先进的多元统计和模式识别算法进行分析，以确定食品样品是否掺假。该统计方法可以同时在非加性多元非参数模型中进行变量选择，用于分析芯片产生的大数据。橄榄油和蜂蜜一直是掺假的目标，将用于验证该技术。预计新的气味检测器将实现不到一分钟的总分析时间，与现有的技术（如气相色谱-质谱法（GC/MS））相比，这是一个数量级的更快和更经济。

Volatile organic compounds (VOCs) constitute a large group of organic chemicals that evaporate easily under normal conditions of temperature and pressure. VOCs are emitted in the atmosphere from a wide variety of natural and anthropogenic sources. The characterization and monitoring of VOCs emitted from different sources is immensely important ranging from biomedical diagnostics, homeland security, food safety and quality to environmental protection. The proposal seeks to develop a new on-site real-time odor sensor based on the principle of electronic noses. The outcome of this proposed research will have a significant impact on reducing the cost, increasing the portability, and increasing the analysis speed and resolution of current VOC detection methodologies. The proposed device will be developed by combining microtechnology, chemistry, and statistics and will be validated for high resolution detection of food adulteration which is a serious and widespread global issue. The research while advancing science and technology for a societal need, will provide invaluable experience for students as they will be trained to work in an interdisciplinary environment. Furthermore, the outreach activities will educate pre-college students how advanced science and engineering can be merged to solve real, current problems.The objective of the proposed research is to develop rapid odor detector implemented by merging the significant concepts in electronic noses and fast gas chromatography (GC) into a small footprint. The focus of this system is the uniquely designed chromatographic chip with multiple capillaries working in parallel. The chip will be fabricated in silicon using microelectromechanical systems (MEMS) technology and will be functionalized using ionic liquids. The major processing steps include deep reactive ion etching followed by silicon-glass anodic bonding. The proposed chromatographic chip will be interfaced with a detector or multiple detectors to generate a rapid odor-print of the sample. The output will be an array of chromatographic responses which will be analyzed using advanced multivariate statistical and pattern recognition algorithms to determine if the food sample has been adulterated. The statistical method can simultaneously perform a variable selection in nonadditive multivariate nonparametric model for analyzing the large data generated by the chip. Olive oil and honey which have been the target of adulteration will be used to validate the technology. It is expected that the new odor detector will achieve a total analysis time of less than a minute which is orders of magnitude faster and more economical when compared to established techniques such as gas chromatography-mass spectrometry (GC/MS).