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

这项研究计划集中在新兴的质谱学(MS)技术的新应用，以解决环境化学中的重要问题。MS根据分子的质量/电荷比来区分分子，是一种具有固有灵敏度和选择性优势的强大分析技术。当采用按照独特的质量裂解路径设计的技术时，MS仪器具有更高的分子分辨率。当半透膜用作样品和质谱仪之间的界面时，它允许连续监测分析物的浓度。直到最近，膜引入MS一直局限于相对挥发性的有机化合物。将使用溶剂受体相的膜入口与大气压电离相耦合，已将该技术扩展到广泛的生物和环境相关化合物。该提案描述了使用质谱仪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性贡献外，本文描述的研究还在污染物归宿模拟、环境工程和生态毒理学方面有更广泛的应用。 实时MS技术为研究质量传输现象、直接观察动态系统中化学浓度的变化以及在移动操作期间绘制地理范围内的化学信息提供了独特的机会。当分析物穿过膜时产生的时间分辨MS信号，提供了内在分子和材料性质的直接探针。这将被用来预测与环境相关的分配系数，并表征新材料的渗透性。此外，由于膜引入质谱仪可以测量溶液中的“游离”化学浓度，因此它可以用来直接观察分配和结合行为。将利用现场反应监测战略，为与环境有关的条件(痕量浓度、多组分、非均质)下的物理和化学过程提供动力学信息。当在移动平台上连续运行时，质谱仪提供在时间和空间上都能分辨的前所未有的数据密度的化学信息。除了可用于区域规模排放清单和暴露研究的地理参考浓度外，本提案还描述了使用化学计量学从非靶标全扫描质谱图中提供成分信息。这项工作直接有助于研究环境中痕量污染物的去向、分布和迁移，并对风险评估、来源解析和应急响应具有影响。

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.