title: Analysis of poly(ethyl methacrylate)s by on-line hyphenation of liquid chromatography at the critical adsorption point and nuclear magnetic resonance spectroscopy
abstract: Liquid chromatography at the critical adsorption point (LC CAP) with on-line NMR detection (on-line LC CAP NMR) was utilized for analysis of tacticity distribution of stereo-regular poly(ethyl methacrylate)s (PEMAs). The separation of a model PEMA sample composed of four constituents with similar molar masses (Mw = (14-16) x 10(3) g mol-1) differing in their tacticity (rr triad content = 0, 33, 68, and 89%) was achieved by LC CAP with a mixed eluent composed of acetone, acetone-d6, and cyclohexane. The tacticity composition within each peak eluted from the LC CAP column was directly determined by a 750-MHz 1H NMR spectrometer that was used as a real-time detector in the continuous-flow mode. Tacticity distribution in a particular PEMA sample with mm/mr/rr = 2/45/53 and narrow molar mass distribution of Mw/Mn = 1.05 has been revealed by the LC CAP NMR technique.
authors.affiliation: Department of Chemistry, Graduate School of Engineering Science, Osaka University, Japan.
authors.initials: T
authors.lastname: Kitayama
authors.initials: M
authors.lastname: Janco
authors.initials: K
authors.lastname: Ute
authors.initials: R
authors.lastname: Niimi
authors.initials: K
authors.lastname: Hatada
authors.initials: D
authors.lastname: Berek