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

在生物复杂性环境-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率光谱-飞行时间质谱仪(IMS-TOF-MS)的仪器，以研究铁生物地球化学循环中鲜为人知的方面：(A)铁在地表水含铬溶解有机物(CDOM)光化学反应中的作用；(B)在海洋系统中作为微量营养素的四种铁络合作用的影响；以及(C)金属蛋白中与血红素和铁硫部分有关的铁的生物化学命运的研究。将设计和制造两个不同的离子迁移率(IM)漂移管，以与现有的质谱仪耦合：一个在飞行时间(TOF)分析器上使用Hadamard多路复用，另一个在IM漂移管上使用Hadamard多路复用。其目标是提高灵敏度，从而能够分析非常稀薄的海水样品，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：斯克里普斯海洋研究所、佐治亚理工学院和斯坦福大学。这些仪器将增强允许高灵敏度和高质量精度的新功能。离子迁移率光谱能力将提供有关铁-大分子络合物的构象和同分异构体信息。直接参与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.