Geoenvironmental Influences on Raman Spectroscopic Monitoring of Chlorinated Solvents

该奖项是根据2009年《美国复苏和再投资法》(公法111-5)资助的。这项研究解决了传感、环境工程和岩土工程交叉领域的多学科挑战，重点是获得地质环境中氯化溶剂的有效和具有代表性的测量结果，以促进对受这些化合物污染的场地进行具有成本效益的表征、监测和管理战略。这些地点在多个尺度上具有巨大的变异性，并经常涉及一系列额外的化学物质。目前可用来在可操作水平上评估氯化溶剂的技术涉及昂贵和复杂的仪器，这些仪器只能评估选定的化合物，在有限的空间范围内提供信息，而且相对较少。利用激光、光子学和电信技术的最新进展，部署基于时间分辨拉曼光谱的分布式氯化溶剂传感系统，是克服这一挑战并改变现场监测状态的巨大潜力。实现这一愿景是一个多阶段的努力，取决于对影响现场拉曼光谱测量的因素建立一个基本的理解。因此，这项工作的目的是在受控的实验室条件下评估地质环境对氯化溶剂的时间分辨拉曼散射观测的影响，以表明现场可能存在的氯化溶剂。具体地说，这项工作将建立在最近开发的创新的光纤耦合、时间分辨拉曼光谱系统的基础上，以1)系统地检查多种化合物背景、荧光团和样品浊度对拉曼观测的影响，2)深入了解在存在荧光团的情况下有效收集拉曼信号所需的数据分析算法，以及3)为现场使用时间分辨拉曼散射进行氯化溶剂研究和更广泛的光谱分析提供建议。总体而言，在光学光谱监测系统方面取得进展，这种系统可以在大范围内以低成本部署，而且几乎实时地提供对广泛化合物的具体分析，这将为地质环境中的化学命运和运输提供前所未有的视角。更广泛地说，这项工作将推动涉及复杂、混浊和/或荧光受限环境中材料的光谱分析的一系列领域，包括水质监测、精准农业、石油勘探、制药质量控制、生物系统分析以及国土安全威胁和环境灾难影响评估。

This award is funded under the American Recovery and Reinvestment Act of 2009(Public Law 111-5).This research addresses a multidisciplinary challenge at the intersection of sensing, environmental engineering and geotechnical engineering focused on obtaining valid and representative measurements of chlorinated solvents in the geoenvironment to facilitate cost-effective characterization, monitoring, and management strategies for sites contaminated with these compounds. These sites are subject to tremendous variability on multiple scales and frequently involve an array of additional chemicals. The technology currently available to assess chlorinated solvents at actionable levels involves costly and sophisticated instruments that can assess only select compounds, provide information over a limited spatial extent, and are available to relatively few. There is great potential to overcome this challenge and transform the state of field monitoring by taking advantage of recent technological advances in lasers, photonics, and telecommunications technology to deploy a distributed chlorinated solvent sensing system based on time-resolved Raman spectroscopy. Achieving this vision is a multi-stage effort, and hinges on establishing a fundamental understanding of the factors affecting in-situ Raman spectroscopic measurements. Thus, the objective of this effort is to assess geoenvironmental influences on time-resolved Raman scattering observations of chlorinated solvents under controlled laboratory conditions indicative of those likely to be present in the field. Specifically, the work will build upon a recently developed innovative prototype fiber-coupled, time-resolved, Raman spectroscopy system, to 1) methodically examine the impact of multi-compound backgrounds, fluorophores, and sample turbidity on Raman observations, 2) provide insight into data analysis algorithms required to effectively collect Raman signatures in the presence of fluorophores, and 3) develop recommendations for field use of time-resolved Raman scattering for chlorinated solvent investigations, and optical spectroscopic analyses more generally. Overall, progress toward optical spectroscopic monitoring systems that can be deployed at low cost over large areas, and yet provide specific analyses of a broad range of chemical compounds in nearly real-time will offer an unprecedented view of chemical fate and transport in the geoenvironment. More broadly, this work will advance a range of fields involving spectroscopic analyses of materials in complex, turbid, and/or fluorescence limited settings including water quality monitoring, precision agriculture, petroleum exploration, pharmaceutical quality control, analyses of biological systems, and assessment of homeland security threats and environmental disaster impact.