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Medium Resolution 1 H‐NMR at 62 MHz as a New Chemically Sensitive Online Detector for Size‐Exclusion Chromatography (SEC–NMR)
Author(s) -
Höpfner Johannes,
Ratzsch KarlFriedrich,
Botha Carlo,
Wilhelm Manfred
Publication year - 2018
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.201700766
Subject(s) - polystyrene , size exclusion chromatography , analytical chemistry (journal) , full width at half maximum , resolution (logic) , spectrometer , polymer , materials science , analyte , chromatography , selectivity , chemistry , organic chemistry , optics , physics , optoelectronics , artificial intelligence , computer science , enzyme , catalysis
A state‐of‐the‐art, medium‐resolution 1 H‐NMR spectrometer (62 MHz) is used as a chemically sensitive online detector for size‐exclusion chromatography of polymers such as polymethylmethacrylate (PMMA) and polystyrene (PS). The method uses protonated eluents and works at typical chromatographic conditions with trace amounts of analytes (<0.5 g L −1 after separation). Strong solvent suppression, e.g., by a factor of 500, is achieved by means of T 1 ‐filtering and mathematical subtraction methods. Substantial improvements are made with respect to previous work in terms of the sensitivity (signal‐to‐noise ratio up to 130:1, PMMA OCH 3 ) and selectivity (peak width, full width half maximum (FWHM) 4 Hz on‐flow). Typical homopolymers and a blend are investigated to deformulate their composition along the dimensions of molecular weight and NMR chemical shift. These results validate this new hyphenated chromatography method, which can greatly facilitate analysis and is much more effective than previously published results.