GOALI: MEMS-Based Preconcentrators with Nano-Structured Adsorbents for Micro Gas Chromatography

GOALI：用于微型气相色谱法的基于 MEMS 的具有纳米结构吸附剂的预浓缩器

• 批准号: 0854242
• 负责人: Masoud Agah
• 金额: $ 34.9万
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-15 至 2013-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0854242&HistoricalAwards=false
• 关键词: GOALI; MEMS; Based; Preconcentrators; Nano

0854242AgahSince the 1950s, gas chromatography (GC) has been a common approach for analysis of volatile mixtures. The use of microelectromechanical systems (MEMS) technology for GC development (ìGC) is a promising approach for developing micro-instruments having lower cost, smaller size, lower power consumption, faster analysis, and greatly increased portability for in-field use compared to their conventional counterparts. These instruments have applications in homeland security, industrial process control, bio-monitoring, and in improving environment quality. Due to the low concentration of volatile and semi-volatile organic compounds (VOC) in ìGCs, a preconcentration step prior to real-time chemical sensor measurement is needed. The ideal preconcentrator would automatically sample the ambient gas and improve the measurement sensitivity by 10-1000 fold while having low power consumption. We will address this challenge by combining and bridging the gap between top-down miniaturized processing (MEMs) and bottom-up self-assembly approaches (nanotechnology). The objective of this work is to employ MEMS technology to develop VOC preconcentrator chips with integrated thermal desorption capability and high surface-to-volume-ratio and to utilize nanotechnology to coat them with nano-structured adsorbents. Four specific goals are proposed: 1) fabricate low-mass (low-power) preconcentrators with on-chip heaters and temperature sensors using high-aspect-ratio silicon etching techniques and a silicon-on-glass wafer process, 2) deposit ionic self-assembled multilayers (ISAM) or alkane functionalized gold nanoparticles on all surfaces of the MEMS-based preconcentrators with nanometer resolutions, 3) coat MEMS preconcentrators with conventional adsorbents such as OV-1 and Tenax and evaluate their performance against those coated with nano-structured materials in terms of desorption width, breakthrough volume, and temperature profile as well as develop new models to predict the behavior of such preconcentrators, and 4) characterize the performance of ìPCs and their corresponding adsorbents for monitoring bioanalytes present in breath and compare the performance of the microchips with conventional industry-standard preconcentrators through collaboration with Convergent Engineering Inc. (CE). We expect to demonstrate the concentration and desorption of n-alkanes (C5-C16) and polyaromatic hydrocarbons as well as breath analytes that vary in ring-size by achieving a concentration factor of 200, desorption widths 0.2s, and power consumptions 1W at 50°C/sec temperature ramps. The ability to self-assemble both polar and non-polar adsorbent materials will enable us to have selective concentration of analytes in a wide range of applications, namely environmental monitoring, homeland security, and biomedicine. The outcome of this project will set an outstanding example of how MEMS and Nanotechnology can become highly complementary methodologies for developing low-cost, low-power, high-performance devices that impact industries across the globe, considering that the worldwide market for GC instruments is estimated to be around $1 billion annually. This research will also advance discovery while promoting teaching and learning at the high school, undergraduate, and graduate levels. This includes: 1) development of gas chromatographic demonstrations using the MEMS-based preconcentrators with nano-structured adsorbents for Virginia Tech?s Society of Physics Students outreach programs to rural, southwestern Virginia high school students, 2) research opportunities for undergraduates at Virginia Tech (VT) and the College of William and Mary (W&M), 3) recruiting of graduate students from under-represented groups into a highly interdisciplinary research program, and 4) incorporation of the project results in the courses taught by the PIs in different departments/institutions, namely VT?s MEMS: from fabrication to application and Nanotechnology, and W&M?s Instrumental Analysis and Advanced Analytical Chemistry and 4) annual joint seminars by VT, W&M, and CE on microsystems applications in biomedicine. Additionally, the outcome of this research will be widely disseminated to the engineering and scientific communities in peer-reviewed journals and in presentation at multidisciplinary conferences, to CE and other industries that use or develop gas chromatography and VOC preconcentrators (microtraps), and in web pages that will serve as resources for off-campus faculty who are teaching undergraduate and graduate analytical chemistry courses that deal with separation science

0854242Agah 自 20 世纪 50 年代以来，气相色谱 (GC) 一直是分析挥发性混合物的常用方法。使用微机电系统 (MEMS) 技术进行 GC 开发 (ìGC) 是开发成本更低、尺寸更小的微型仪器的一种有前景的方法。与传统同类仪器相比，这些仪器具有更低的功耗、更快的分析速度以及大大提高的现场使用便携性。由于 ìGC 中挥发性和半挥发性有机化合物 (VOC) 浓度较低，因此需要在实时化学传感器测量之前进行预浓缩步骤。理想的预浓缩器会自动进行。对环境气体进行采样，并将测量灵敏度提高 10-1000 倍，同时保持低功耗。我们将通过结合和弥合自上而下的小型化处理 (MEM) 和技术之间的差距来应对这一挑战。自下而上的自组装方法（纳米技术）是利用 MEMS 技术开发具有集成热解吸能力和高表面积体积比的 VOC 预浓缩器芯片，并利用纳米技术对其进行纳米涂层涂覆。提出了四个具体目标：1）使用高深宽比硅蚀刻技术和技术制造带有片上加热器和温度传感器的低质量（低功耗）预浓缩器。玻璃硅晶圆工艺，2) 在基于 MEMS 的预浓缩器的所有表面上以纳米分辨率沉积离子自组装多层 (ISAM) 或烷烃功能化金纳米粒子，3) 用传统吸附剂（如 OV-1）涂覆 MEMS 预浓缩器和 Tenax 并评估它们与涂有纳米结构材料的材料在解吸宽度、突破体积和温度分布方面的性能，并开发新模型预测此类预浓缩器的行为，4) 表征用于监测呼吸中存在的生物分析物的 ìPC 及其相应吸附剂的性能，并通过与传统工程公司 (CE) 的合作将微芯片与行业标准预浓缩器的性能进行比较。通过实现环尺寸变化来演示正构烷烃 (C5-C16) 和多环芳烃以及呼吸分析物的浓缩和解吸浓缩因子为 200，解吸宽度为 0.2 秒，在 50°C/秒的温度梯度下功耗为 1W。自组装极性和非极性吸附材料的能力将使我们能够在较宽的范围内选择性地浓缩分析物。该项目的成果将为 MEMS 和纳米技术如何成为开发低成本、考虑到气相色谱仪器的全球市场每年约为 10 亿美元，这项研究还将推动发现，同时促进高中、本科生和大学的教学。这包括：1) 使用基于 MEMS 的预浓缩器和纳米结构吸附剂为弗吉尼亚理工大学物理系学生的推广项目开发气相色谱演示，2) 为弗吉尼亚州西南部的农村高中生提供研究机会。弗吉尼亚理工大学 (VT) 和威廉玛丽学院 (W&M) 的本科生，3) 从代表性不足的群体中招募研究生参与高度跨学科的研究项目，以及 4) 将项目成果纳入由弗吉尼亚理工大学 (VT) 和威廉玛丽学院 (W&M) 教授的课程中不同部门/机构的PI，即VT的MEMS：从制造到应用和纳米技术，以及W&M的仪器分析和高级分析化学以及4）VT的年度联合研讨会，此外，这项研究成果将在同行评审期刊上以及在多学科会议上的演示中向工程和科学界、CE 和其他使用或开发气相色谱法的行业广泛传播。和 VOC 预浓缩器（微捕集器），以及网页，这些网页将作为校外教师的资源，这些教师正在教授处理分离科学的本科生和研究生分析化学课程