Panoptic Mass Spectrometry

Ohio State University, The, Columbus OH

Investigators

Abstract

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.