title: Remotely detected NMR for the characterization of flow and fast chromatographic separations using organic polymer monoliths.
abstract: An application of remotely detected magnetic resonance imaging is demonstrated for the characterization of flow and the detection of fast, small molecule separations within hypercrosslinked polymer monoliths. The hyper-cross-linked monoliths exhibited excellent ruggedness, with a transit time relative standard deviation of less than 2.1%, even after more than 300 column volumes were pumped through at high pressure and flow. Magnetic resonance imaging enabled high-resolution intensity and velocity-encoded images of mobile phase flow through the monolith. The images confirm that the presence of a polymer monolith within the capillary disrupts the parabolic laminar flow profile that is characteristic of mobile phase flow within an open tube. As a result, the mobile phase and analytes are equally distributed in the radial direction throughout the monolith. Also, in-line monitoring of chromatographic separations of small molecules at high flow rates is shown. The coupling of monolithic chromatography columns and NMR provides both real-time peak detection and chemical shift information for small aromatic molecules. These experiments demonstrate the unique power of magnetic resonance, both direct and remote, in studying chromatographic processes.
authors.affiliation: Department of Chemistry, University of California-Berkeley, Berkeley, California 94720, United States.
authors.forename: Thomas Z
authors.initials: TZ
authors.lastname: Teisseyre
authors.forename: Jiri
authors.initials: J
authors.lastname: Urban
authors.forename: Nicholas W
authors.initials: NW
authors.lastname: Halpern-Manners
authors.forename: Stuart D
authors.initials: SD
authors.lastname: Chambers
authors.forename: Vikram S
authors.initials: VS
authors.lastname: Bajaj
authors.forename: Frantisek
authors.initials: F
authors.lastname: Svec
authors.forename: Alexander
authors.initials: A
authors.lastname: Pines
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009930:Organic Chemicals / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*
chemical_list: D009930:Organic Chemicals; D011108:Polymers