Panoptic Mass Spectrometry

在化学系化学测量和成像计划的支持下，俄亥俄州立大学的Abraham Badu-Tawiah教授和他的研究小组正在开发一种新的质谱学平台，能够在单个实验中分析超小样本量中的所有化学物种，这可能是代谢组学相关技术的重大进步。质谱仪测量化学物质的质量电荷比，这是一个普遍的参数，应该使这种分析技术在不同的领域得到广泛应用。目前，这种能力是通过对不同化合物使用不同的离子源实现的。这项研究的目标是开发一种单一的通用(全光)离子源，可以分析广泛的化学物种。普适性的概念从对不同化学物质的检测扩展到包括对液体、固体和气相样品的分析，所有这些都使用相同的全景离子源。化学仪器、新的电离方法和处理超小样品体积的学科非常适合各级科学家的教育。教育宣传活动是完全整合的，旨在直接影响学生在其教育经历的早期阶段(K-12)。由于建议的实验很简单，这个小组处于有利地位，可以向学生--特别是来自STEM(科学、技术、工程和数学)领域代表性较低的群体的学生--介绍跨学科科学，建立他们的信心，并鼓励他们以一种广泛的、基于发现的方式思考科学。与小量分析相关的挑战包括分析前的分馏效率低下，导致显著的基质效应。这项研究的学术价值围绕着三个新概念的串联发展。首先，动态电喷雾过程将使时间上不同的电离机制能够从单个发射器启动，以电离不同的化合物，并基于溶液相迁移率提供所涉及的化学物种的时间分离。其次，动态喷雾过程中包含的等离子体电离将允许分析所有三种状态的物质(即液体、固体和气相样品)中的极性和非极性化合物，从而建立第一个全景(通用)离子源。第三，离子产生的特殊机制(特别是基于环境等离子体化学的机制)将使质谱仪能够在四种可能的模式(四象限)下工作，以检测来自全光离子源的所有可能的离子类型(M·+、M·-、[M+H]+、[M-H]+、[M-H]-、[M+NH]n+)。因此，将创建一个新的全光质谱分析平台，其中通用离子源将与四象限质量分析相结合。我们期待这项研究将直接进样质谱仪转变为高性能的分析系统，其中低分辨率质谱仪可以更有效地用于复杂混合物的分析。这一能力是通过实现在线样品处理实现的，包括时间分离和化学反应。选择的特定反应(例如电荷反转、酯交换和C=C键的环氧化)有可能通过在多个异构体水平上进行脂质分析来扩大脂质组学的范围。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Chemical Measurement and Imaging Program in the Division of Chemistry, Professor Abraham Badu-Tawiah and his research group at Ohio State University is developing a new mass spectrometry platform to enable the analysis of all kinds of chemical species in ultra-small sample volumes in a single experiment, a potentially significant advance in metabolomics-related technology. Mass spectrometers measure mass-to-charge ratio of chemical species, a universal parameter that should make this analytical technique widely applicable across diverse fields. Currently, this capability is realized using different ion sources for different compounds. The goal of this research is to develop a single universal (panoptic) ion source that can analyze a wide range of chemical species. The idea of universality is expanded from the detection of diverse chemicals to include the analyses of liquid-, solid-, and vapor-phase samples, all using the same panoptic ion source. The subjects of chemical instrumentation, new ionization methods, and the processing of ultra-small sample volumes are well suited for the education of scientists at all levels. Education-outreach activities are fully integrated and are designed to directly impact students in the early stages (K-12) of their educational experience. Due to the simplicity of the proposed experiments, this group is well-positioned to introduce students – particularly from groups underrepresented in the STEM (science, technology, engineering and mathematics) fields – to interdisciplinary science, build their confidence and encourage them to think of science in a broad, discovery-based manner. Challenges associated with small volume analysis include inefficient fractionation prior to analysis, leading to significant matrix effects. The intellectual merits of this research revolve around the tandem development of three novel concepts. First, a dynamic electrospray process will enable temporally distinct ionization mechanisms to be initiated from a single emitter to ionize different compounds, as well as to offer temporal separation of chemical species involved, based on solution-phase mobility. Second, the plasma ionization included in the dynamic spray process will allow analysis of polar and nonpolar compounds in all three states of matter (i.e., liquid-, solid-, and vapor-phase samples), thus establishing the first panoptic (universal) ion source. Third, the specific mechanisms of ion generation (particularly those based on ambient plasma chemistry) will enable mass spectrometer operation in four conceivable modes (four quadrant) to detect all possible ion types (M•+, M•-, [M+H]+, [M-H]+, [M-H]-, [M+nH]n+) originating from the panoptic ion source. Therefore, a new panoptic mass spectrometry platform will be created in which the universal ion source will be coupled with a four-quadrant mass analyses. We expect this research to transform direct infusion mass spectrometry into a high-performance analytical system in which low-resolution mass spectrometers can be used more effectively for complex mixture analysis. This capability is made possible by enabling online sample processing, including temporal separation and chemical reactions. The specific reactions selected (e.g., charge inversion, transesterification, and epoxidation of C=C bonds) have potential to expand the scope of lipidomics by enabling lipid analysis at multiple isomer levels.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.