Real-time Measurements in Real-world Samples: Fate and Distribution of Trace Organic Contaminants by Direct Mass Spectrometry

这项研究计划的核心是开发和应用创新的实时质谱仪(MS)技术，用于直接和连续测量环境和人类健康的分子决定因素。Direct MS是一个极其强大的分析平台，可实现高通量、时间分辨率和现场测量。这些独特的能力通过在实时监测和高级时空分析中的应用提供复杂样品中的分子水平信息，解决了目前对新出现的令人关注的污染物的命运和分布的理解的几个长期制约因素。这项研究将1)开发新的污染物类别的直接采样方法，2)研究复杂介质中的环境化学过程，3)动员MS进行空气、水和沉积物的现场测量。这些目标是通过开发快速、简单和可靠的灵敏和选择性的MS方法来实现的。在没有层析分离的情况下，直接质谱仪依赖于样品引入方法、电离机制和质谱仪所赋予的选择性。在膜引入方法中，分子渗透到受体中，受体不断地注入质谱计。了解控制质量传输的因素使我们能够提高选择性，并使用新材料、电场梯度和化学修饰剂设计新的基于膜的策略。场不对称波形离子迁移率光谱代表了直接MS应用的理想配对，因为它提供了快速、正交的分离(基于差动迁移率)。它很容易与高分辨率的实验室仪器和低成本的便携式MS搭配使用，为后续的现场应用提供了开发方法的机会。时间分辨MS技术提供了对影响环境中污染物转化的化学和物理过程的机制的独特见解。采用膜引入MS技术跟踪非均相样品中分析物浓度的变化，包括微量污染物在微塑料上的吸附和油砂工艺水中环烷酸的光化学降解。质子转移反应质谱仪提供对挥发性有机化合物的连续道路测量，产生以邻域尺度绘制的化学浓度图，并提供“指纹”来源和分摊贡献的组成信息。这里描述的研究通过开发下一代方法来提供真实世界样品中的实时分子水平信息，从而在环境化学分析中开辟了重要的新领域。在“何时”和“需要的地方”提供化学信息，能够以前所未有的时空分辨率进行环境评估和取证。因此，这项研究直接为环境保护和健康社区做出了贡献。

This research program centres on the development and application of innovative real-time mass spectrometry (MS) techniques for the direct and continuous measurement of molecular determinants of environmental and human health. Direct MS is an extremely powerful analytical platform that enables high throughput, time-resolved, and in-situ measurements. These unique capabilities address several long-standing constraints to current understanding of the fate and distribution of contaminants of emerging concern by providing molecular level information in complex samples with applications in real-time monitoring and advanced spatiotemporal analysis. This research will 1) develop novel direct sampling methods for new contaminant classes, 2) study environmental chemical processes in complex media, and 3) mobilize MS for in-field measurements in air, water, and sediments. These goals are realized by developing sensitive and selective MS methods that are fast, simple, and robust. In the absence of chromatographic separation, direct MS relies on selectivity imparted by the sample introduction method, ionization mechanism, and the mass spectrometer. In membrane introduction methods, molecules permeate into an acceptor which is continuously infused into a mass spectrometer. Understanding factors that control mass transport allow us to improve selectivity and design novel membrane-based strategies using new materials, electrical gradients, and chemical modifiers. Field asymmetric waveform ion mobility spectrometry represents an ideal pairing with direct MS applications as it provides fast, orthogonal separation (based on differential mobility). It is readily paired with high resolution, lab-based instruments and lower cost, portable MS, providing the opportunity to develop methods for subsequent in-field applications. Time-resolved MS techniques provide unique insight into the mechanisms of chemical and physical processes that affect the transformation of contaminants in the environment. Membrane introduction MS techniques are employed to follow changes in the concentration of analytes in heterogeneous samples including sorption of trace contaminants on microplastics and photochemical degradation of naphthenic acids in oil sands process waters. Proton-transfer reaction MS provides continuous on-road measurements of volatile organic compounds that yields chemical concentrations mapped at the neighborhood scale and compositional information to `finger-print' sources and apportion contributions. The research described here opens important new territory in environmental chemical analysis by developing next-generation methods to provide real-time molecular level information in real-world samples. Providing chemical information `when' and `where' it is needed enables environmental assessment and forensics at unprecedented spatiotemporal resolution. As such, this research contributes directly to environmental protection and healthy communities.