Implanted Membranes for Characterization and Monitoring

NIH SBIR二期项目将使达科塔技术公司(DTI)能够完成中空纤维膜(HFM)采样系统的开发，该系统可提供地下水中挥发性有机化合物(VOCs)的分析质量数据。该系统用途广泛，功能全面；它包括植入HFM采样器的方法和硬件、有效收集从地下水透过膜渗透的蒸汽的方法和硬件，以及气相色谱样品分析的最后一步。测量的基础是从地下水地层到管腔的VOC渗透汽化。 中空纤维。在管腔内形成的顶腔通过载气返回表面。通过控制捕获时间，可以在很大范围内调整检测限。概念验证是通过实验室研究和选定的一系列实地研究确定的。一个HFM采样器对另一个采样器的响应不到10%。MTBE、苯、甲苯、三氯乙烯和四氯乙烯等对环境有重大影响的污染物可以在每升5微克以下的浓度下准确测量。第二阶段的活动包括渗透热力学和动力学的综合实验室研究、替代膜材料和几何形状的评估、部署和采样硬件的改进以及广泛的实地研究。拟议的系统将为环境顾问、监管机构和工地所有者提供极大改进的能力，以全面确定VOC污染的横向和垂直程度，从而导致更快和更有效的补救工作。这项研究的最终受益者将是依赖清洁、健康饮用水供应的公民。

This NIH SBIR Phase II project will enable Dakota Technologies, Inc. (DTI) to complete development of a hollow-fiber membrane (HFM) sampling system that provides analytical quality data on volatile organic compounds (VOCs) in groundwater. The system is versatile and comprehensive; it incorporates methods and hardware for implanting the HFM samplers, methods and hardware for efficiently collecting vapors that permeate from the groundwater through the membrane, and the end step of gas chromatographic sample analysis. The basis of the measurement is VOC pervaporation from the groundwater formation into the lumen of the hollow fiber. The headspace developed in the lumen is returned to the surface via a carrier gas. Limits of detection can be adjusted over a wide range by controlling the time of trapping. Proof of concept was established through laboratory studies and a selected set of field studies. The response from one HFM sampler to another varied less than 10%. Environmentally significant contaminants such as MTBE, benzene, toluene, trichloroethylene, and perchloroethylene can be accurately measured at concentrations below 5 micrograms per liter. The Phase II activities include comprehensive laboratory studies of the permeation thermodynamics and kinetics, evaluation of alternative membrane materials and geometries, refinement of the deployment and sampling hardware, and extensive field studies. The proposed system will provide environmental consultants, regulators, and site owners vastly improved capability to fully characterize the lateral and vertical extent of VOC contamination, leading to faster and more effective remedial efforts. The ultimate beneficiaries of the research will be the citizens who rely on a supply of clean, healthy drinking water.