Speedy, Robust and Quantitative Analysis of Polyolefins Using Sensitivity-Enhanced 13C NMR Spectroscopy

Abstract

We report a novel NMR methodology that enables quantitative analysis of polyolefin materials in a fast and robust manner. The method is named quantitative adiabatic refocused insensitive nuclei enhanced by polarization transfer (QA-RINEPT). With the aid of adiabatic pulses, QA-RINEPT enables rigorous and controllable polarization transfer via combining the advantage of polarization transfer with the concept of response factor calibration that is widely used in chromatography to yield predictable 13C NMR spectra. The spectra obtained remain highly sensitive without compromising the quantitative nature. The effectiveness and robustness of QA-RINEPT have been demonstrated using a model compound on three NMR instruments equipped with different consoles and probes. QA-RINEPT further demonstrates its remarkable capability with polyolefin materials by saving up to 50–60× experimental time. The 13C NMR spectra obtained have been analyzed and compared with the standard quantitative single-pulse method by two indiv...