Unveiling an NMR-Invisible Fraction of Polymers in Solution by Saturation Transfer Difference.

ABSTRACT: The observation of signals in solution NMR requires nuclei with sufficiently large transverse relaxation times (T₂). Otherwise, broad signals embedded in the baseline afford an invisible fraction of nuclei (IF). Based on the STD (saturation transfer difference) sequence, IF-STD is presented as a quick tool to unveil IF in the ¹H NMR spectra of polymers. The saturation of a polymer in a region of the NMR spectrum with IF (very short ¹H T₂) results in an efficient propagation of the magnetization by spin diffusion through the network of protons to a visible-invisible interphase with larger ¹H T₂ (STD_on). Subtracting this spectrum from one recorded without saturation (STD_off) produces

SUBMITTER: Novoa-Carballal R 

PROVIDER: S-EPMC8697556 | biostudies-literature | 2021 Dec

REPOSITORIES: biostudies-literature