A Miniaturized GC with MEMS-Enabled Selective Preconcentration for Monitoring Exp

具有 MEMS 选择性预富集功能的小型气相色谱仪，用于监测实验

• 批准号: 8359250
• 负责人: Masoud Agah
• 金额: $ 18.59万
• 依托单位: VIRGINIA POLYTECHNIC INST AND ST UNIV
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-01 至 2014-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8359250
• 关键词: Miniaturized; GC; MEMS; Enabled; Selective

DESCRIPTION (provided by applicant): This research proposal is aimed at developing a miniaturized gas chromatography system with selective adsorption capability to identify air hazardous pollutants (HAPs) found in transportation-related and other workplaces. Exposure to HAPs has been linked to a variety of health effects, such as cancer, asthma, autism, reduced fertility, and lower intelligence. Development of effective strategies for reducing occupational exposure to HAPs requires accurate, time-resolved measurement of exposure, but doing so is restricted by the unavailability of compact, lightweight, inexpensive portable analytical instruments. Current practice typically requires collection of a sample in the field using a canister or sorbent tube, transport to the lab, and then application of gas chromatography with a detector to identify and quantify the species present in the environment. This proposal addresses the need for lower cost, compact exposure monitors by merging microelectromechanical systems (MEMS) technology, microelectronics, and analytical chemistry to develop a portable GC system containing a dual-preconcentrator stage for selective adsorption of analytes, separation column with embedded thermal conductivity detector (TCD), and a microprocessor-based controller. The overall iPad-size system will have a concentration factor > 10,000, separation efficiency > 10,000 plates, an overall detection limit < 1ppb, and the ability of selective trapping of analytes of interest enabling a complete GC run from sample collection to detection in less than 10 min. The specific aims of the research described in this proposal are as follows: 1) to design, develop, and evaluate the ¿GC system for measuring exposure to HAPs and 2) to evaluate the system functionality for on-field HAP monitoring through comparison with conventional techniques. Aim 1 is focused on fabricating the preconcentrator with on-chip thermal desorption capability, implementing the dual-preconcentration scheme for selective adsorption, fabricating the column with on-chip TCD and oven, and designing and implementing the brain of the system (electronics) and the required system platform. Through laboratory testing, the MEMS components will be evaluated in terms of concentration and separation characteristics to enable the identification of key compounds in three classes of HAPs: aromatic solvents; polycyclic aromatic hydrocarbons, and non-aromatic hydrocarbons. In Aim 2, the system effectiveness at detecting and quantifying the HAPs of interest will be evaluated in controlled, paired- sample testing to compare results with those obtained by conventional methods using active sampling through a sorbent tube followed by thermal desorption and gas chromatography. We will deploy both the ¿GC system and sorbent tube coupled with a pump at two transportation-related workplaces: a municipal airport (Virginia Tech Montgomery Executive Airport) and bus maintenance facility (Blacksburg Transit). While focused on exposure monitoring, the scientific and technological impacts of this project may extend to other applications if this exploratory research is accomplished successfully. PUBLIC HEALTH RELEVANCE: The goal of the project is to develop a smart portable gas analyzer that can be used to measure hazardous air pollutants in (near) real-time in transportation-related and other workplaces. It can replace cumbersome sampling methods that must be followed by costly analysis in a laboratory. This programmable system is small enough that it can easily be worn to provide a measure of personal exposure to hazardous air pollutants.

描述（由申请人提供）：本研究计划旨在开发一种具有选择性吸附能力的小型气相色谱系统，以识别交通相关和其他工作场所中发现的空气有害污染物（HAPs）。接触HAPs与多种健康影响有关，如癌症、哮喘、自闭症、生育能力下降和智力低下。制定减少职业接触HAPs的有效战略需要对接触量进行精确的、时间分辨的测量，但由于缺乏紧凑、轻便、廉价的便携式分析仪器，这方面的工作受到限制。目前的做法通常需要在现场使用罐或吸收管收集样品，运送到实验室，然后使用气相色谱法和检测器来识别和量化环境中存在的物种。该提案通过将微机电系统（MEMS）技术、微电子技术和分析化学相结合，开发出一种便携式GC系统，该系统包含用于选择性吸附分析物的双预富集级、带有嵌入式导热检测器（TCD）的分离柱和基于微处理器的控制器，以满足对低成本、紧凑暴露监视器的需求。整个ipad大小的系统将具有浓度因子> 10,000，分离效率> 10,000板，总检测限< 1ppb，以及选择性捕获感兴趣的分析物的能力，从而在不到10分钟的时间内完成从样品收集到检测的GC运行。本提案中描述的具体研究目的如下：1)设计、开发和评估用于测量HAP暴露的¿GC系统；2)通过与传统技术的比较，评估系统在现场HAP监测中的功能。目标1的重点是制造具有片上热解吸能力的预富集器，实现选择性吸附的双预富集方案，用片上TCD和烘箱制造色谱柱，设计和实现系统的大脑（电子）和所需的系统平台。通过实验室测试，MEMS组件将在浓度和分离特性方面进行评估，以识别三类HAPs中的关键化合物：芳香族溶剂；多环芳烃和非芳烃。在目标2中，系统在检测和量化感兴趣的HAPs方面的有效性将在受控的配对样品测试中进行评估，以将结果与通过吸附管进行热解吸和气相色谱的主动采样的传统方法获得的结果进行比较。我们将在两个交通相关的工作场所部署GC系统和吸附管以及泵：市政机场（弗吉尼亚理工大学蒙哥马利行政机场）和公共汽车维修设施（布莱克斯堡运输）。虽然该项目侧重于暴露监测，但如果这项探索性研究成功完成，其科学和技术影响可能会扩展到其他应用领域。