"The coupling of our remote NMR/MRI technology with monolithic chromatography columns in a microfluidic chip enables us to obtain high resolution, velocity-encoded images of a mobile phase flowing through the stationary phase," Bajaj says. "Our technique provides both real-time peak detection and chemical shift information for small aromatic molecules, and demonstrates the unique power of magnetic resonance, both direct and remote, in studying chromatographic processes."
The coupling of remote NMR/MRI to chromatography was made possible by the polymer monolithic column, a technology developed by Analytical Chemistry paper co-author Frantisek Svec, a chemist who directs the Organic and Macromolecular Synthesis facility at Berkeley Lab's Molecular Foundry, a DOE nanoscience center. In conventional chromatography, the stationary phase column is typically filled with porous polymer beads or some other discrete medium whose physical or chemical properties modulate the diffusion rates of analytes passing through. In Svec's stationary phase, a chromatography column is filled with a monolithic solid polymer meaning it is a single, continuous piece - that is perforated throughout with nanoscopic pores.
"Polymer monoliths as a separation media can be compared to a single large particle that does not contain inter-particular voids," Svec says. "As a result, all the mobile phase must pass through the stationary phase as convective flow rather than diffusion during chromatographic processes. This convective flow greatly accelerates the rate of analyte separation."
The remote NMR/MRI technology whose development was led by Pines won a 2011 R&D 100 Award
|Contact: Lynn Yarris|
DOE/Lawrence Berkeley National Laboratory