NSF Award
2305102
With support from the Chemical Measurement and Imaging Program in the Division of Chemistry, Professor Maryanne Collinson and her group at Virginia Commonwealth University are seeking to improve the separation of complex biological samples by exploring an alternate paradigm in separation science: the use of mixed-mode gradient stationary phases. These materials are packed into stainless steel tubes and the strength of the chemical interaction sites on the stationary phase is varied along the length of the tube. When coupled with a traditional liquid mobile phase gradient, which displaces the analyte molecules sequentially as the strength of mobile phase solvent is increased, such materials have the potential to provide significantly improved selectivity in the separation of large biomolecules. An important obstacle to realizing such improved selectivity in practice is the ability to experimentally fabricate these mixed-mode gradient stationary phases in a controlled and predictable fashion. This challenge will be addressed in the present work through a combination of experimental design and simulation via a continued collaboration with Dr. Sarah Rutan, an expert in the field of chromatographic simulations and their predictive power. This will project provide opportunities for both scientific discovery and student training and learning. This research is expected to advance knowledge in the field of separation science, particularly in areas that target the analysis of large, biologically relevant molecules including proteins, peptides, and ultimately monoclonal antibodies that are of particular interest in the development of novel biologic pharmaceuticals. It explores an original concept aimed to improve the selectivity of a separation and ultimately the resolution of chemically similar analytes within complex protein samples.Students involved in this project will obtain valuable expertise in the packing of chromatography columns, the modification of silica using silane chemistry, and its detailed characterization using TGA and other spectroscopic and microscopic tools. Simultaneously, they will become experts in LC and the separation of mixtures of biomolecules making them uniquely employable in the biopharmaceutical field. <br/><br/>In most chemical separations, the gradient is in the mobile phase. An alternate paradigm puts the gradient on the stationary phase. Recent simulated work has shown that dual stationary phase gradients when coupled with a mobile phase gradient can “open up previously unseen selectivities” in the separation of large biomolecules. In the present work, the challenges associated with the fabrication and implementation of such mixed-mode stationary phase gradients suitable for biomolecule separations will be addressed. Through the course of this work, new approaches will be explored to strategically modify a particle-packed silica column with a functionalized monochlorosilane (e.g., phenyl, C8, C4,...) in a gradient fashion. The steepness of the gradients will be varied and optimized so that when coupled with a mobile phase gradient synergistic selectivity and/or band compression will be observed in the separation of biomolecules. Simulation methods will be developed to predict the chromatographic response and to optimize the conditions for column fabrication. The gradient lengths and compositions needed to obtain optimum separations will be obtained by coupling simulations with experiments, thus avoiding the trial-and-error approach usually used in materials development. Over the long term, the new column technology and accompanying simulations developed through this research have the potential to impact the fields of proteomics and lipidomics, as well as two-dimensional liquid chromatographic separations.<br/><br/>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.
