Fate and Distribution of Trace Organics Using On-line Mass Spectrometry

这个研究项目集中在新兴的质谱（MS）技术的新应用上，以解决环境化学中的重要问题。质谱法根据分子的质荷比来区分分子，是一种具有固有灵敏度和选择性优势的强大分析技术。当设计的技术遵循独特的质量碎片路径时，质谱仪器具有更大的分子分辨能力。当使用半透膜作为样品和质谱仪之间的界面时，它可以连续监测分析物的浓度。直到最近，膜导入质谱一直局限于相对挥发性的有机化合物。采用溶剂受体相的耦合膜入口与大气压电离已经将该技术扩展到广泛的生物和环境相关化合物。本提案描述了使用质谱直接测量环境和人类健康的分子决定因素。除了对环境化学领域的基础贡献之外，这里描述的研究在污染物命运建模，环境工程和生态毒理学方面有更广泛的应用。

This research program is centred on the novel application of emerging mass spectrometry (MS) techniques to address important questions in environmental chemistry. MS discriminates between molecules based on their mass-to-charge ratio and is a powerful analytical technique with inherent sensitivity and selectivity advantages. When techniques designed to follow unique mass fragmentation pathways are employed, MS instruments have even greater molecular resolving power. When a semi-permeable membrane is used as an interface between the sample and the mass spectrometer, it allows the concentration of analytes to be continuously monitored. Until recently, membrane introduction MS has been limited to relatively volatile organic compounds. Coupling membrane inlets employing a solvent acceptor phase to atmospheric pressure ionization has extended the technique to a wide range of biologically and environmentally relevant compounds. This proposal describes the use of MS to directly measure molecular determinants of environmental and human health. In addition to foundational contributions to the field of environmental chemistry the research described here has broader application in contaminant fate modeling, environmental engineering, and eco-toxicology. Real-time MS techniques provide unique opportunities for the investigation of mass transport phenomena, the direct observation of changes in chemical concentration in dynamic systems, and the ability to map chemical information over geographic scales during mobile operations. The time-resolved MS signals generated as analytes permeate through a membrane, provide a direct probe of intrinsic molecular and material properties. This will be used to predict environmentally relevant distribution coefficients and to characterize the permeability of new materials. Furthermore, since membrane introduction MS measures the free' chemical concentration in solution, it can employed for the direct observation of partitioning and binding behaviour. The use of in-situ reaction monitoring strategies will be utilized to provide kinetic information for physical and chemical processes at environmentally relevant conditions (trace concentrations, multiple components, heterogeneous). When operated continuously on a mobile platform, mass spectrometers provide chemical information with unprecedented data density that is resolved in both time and space. In addition to geographically referenced concentrations, which can be used for regional scale emission inventories and exposure studies, this proposal describes the use of chemometrics to provide compositional information from non-targeted full scan mass spectra. This work contributes directly to the study of fate, distribution, and transport of trace contaminants in the environment and has implications to risk assessment, source apportionment and emergency response.