title: SEC-MR-NMR: online coupling of size exclusion chromatography and medium resolution NMR spectroscopy.
abstract: Online coupling of size exclusion chromatography together with medium resolution nuclear magnetic resonance (SEC-MR-NMR) might be one solution to the problem of chemically sensitive detection in liquid polymer chromatography. By use of a combination of SEC with a table-top, specially designed 20 MHz NMR spectrometer, based on a permanent magnet, online (1) H NMR spectra of SEC fractions can be obtained. The integration of digital filters, mechanical shims and electronic shims led to substantially improved sensitivity and chemical selectivity compared to former TD (time domain) 20 MHz instruments. (1) H NMR spectra of PMMA and PS homopolymers as well as PS-PMMA block copolymers were of sufficient quality to enable detection and de-formulation of unknown polymer compounds. (1) H NMR spectra of acceptable resolution and S/N ratio were collected online during the chromatography. The SEC separation online with the NMR measurements performed well and resulted in the proof of principle of the SEC-MR-NMR combination.
authors.affiliation: Institute for Chemical Technology and Polymer Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstraße 18, 76128 Karlsruhe, Germany; Institute of Mechanical Process Engineering and Mechanics, SRG10-2, Karlsruhe Institute of Technology (KIT), Adenauerring 20b, 76131 Karlsruhe, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Cudaj
authors.forename: Gisela
authors.initials: G
authors.lastname: Guthausen
authors.forename: Thorsten
authors.initials: T
authors.lastname: Hofe
authors.forename: Manfred
authors.initials: M
authors.lastname: Wilhelm
mesh_terms: D002850:Chromatography, Gel / Q000295:instrumentation*; D004867:Equipment Design; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation*; D011108:Polymers / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D011108:Polymers