Multiplexed Ion-Mobility Time-of-Flight Mass Spectrometry for the Study of Iron Biogeochemical Cycling in Seawater

在环境中的生物复杂性-环境活动仪器开发（BE-IDEA）计划的支持下，斯坦福大学化学系的Richard Zare将开发基于离子迁移谱-飞行时间质谱仪的仪器（IMS-TOF-MS）研究铁地球化学循环的知之甚少的方面：（a）铁在地表水有色溶解有机物（CDOM）的光化学反应性中的作用;（B）四吡咯对铁络合作用的影响，作为海洋系统中的微量营养素;以及（c）研究与金属蛋白中的血红素和铁-硫部分相关的铁的生物化学命运。 两个不同的离子迁移率（IM）漂移管将被设计和建造耦合到现有的质谱仪：一个采用Hadamard多路复用的飞行时间（TOF）分析仪和另一个使用Hadamard多路复用的IM漂移管。 其目标是提高灵敏度，允许非常稀释的海水样品的分析，同时提供二维和三维信息，以确定未知的铁结合化学物种。 该项目涉及三个机构的研究人员：斯克里普斯海洋学研究所、格鲁吉亚理工学院和斯坦福大学。 这些仪器将提高新的功能，允许高灵敏度和高质量精度。 离子迁移谱的能力将提供有关铁-大分子复合物的构象和异构体信息。 直接参与该项目建设阶段的研究生和本科生将接受仪器开发和环境活动方面的培训。 研究结果对于寻求开发专注于环境分析的质谱仪器的公司也将是有价值的。

With support from the Biocomplexity in the Environment - Instrument Development for Environmental Activities (BE-IDEA) Program, Richard Zare in the Chemistry Department at Stanford University will develop instrumentation based on ion-mobility spectrometry - time-of-flight mass spectrometer (IMS-TOF-MS) to investigate poorly understood aspects of the iron biogeochemical cycle: (a) the role of iron in the photochemical reactivity of surface water Chromophoric Dissolved Organic Matter (CDOM); (b) the influence of iron complexation by tetrapyrroles in its role as a micronutrient in marine systems; and (c) study of the biochemical fate of iron associated with heme and iron-sulfur moieties in metallo-proteins. Two different Ion-Mobility (IM) drift tubes will be designed and built to be coupled to existing mass spectrometers: one employing Hadamard multiplexing at the Time of Flight (TOF) analyzer and another that uses Hadamard multiplexing at the IM drift tube. The goal is to improve sensitivity allowing for the analysis of very dilute seawater samples while simultaneously providing two- and three-dimensional information to identify unknown iron-binding chemical species. This project involves researchers at three institutions: Scripps Institute of Oceanography, Georgia Institute of Technology and Stanford University. These instruments will boost novel features allowing high sensitivity and high mass accuracy. The ion mobility spectrometry capability will provide conformation and isomeric information about iron-macromolecular complexes. Graduate and undergraduate students directly involved in the building stages of the project will be trained in instrument development and environmental activities. Results will also be valuable for companies seeking to develop mass spectrometry instrumentation focused on environmental analysis.