1H NMR z-spectra of acetate methyl in stretched hydrogels: Quantum-mechanical description and Markov chain Monte Carlo relaxation-parameter estimation
Abstract
The 1H NMR signal of the methyl group of sodium acetate is shown to be a triplet in the anisotropic environment of stretched gelatin gel. The multiplet structure of the signal is due to the intra-methyl residual dipolar couplings. The relaxation properties of the spin system were probed by recording steady-state irradiation envelopes ('z-spectra'). A quantum-mechanical model based on irreducible spherical tensors formed by the three magnetically equivalent spins of the methyl group was used to simulate and fit experimental z-spectra. The multiple parameter values of the relaxation model were estimated by using a Bayesian-based Markov chain Monte Carlo algorithm.
- Publication:
-
Journal of Magnetic Resonance
- Pub Date:
- January 2015
- DOI:
- 10.1016/j.jmr.2014.11.001
- Bibcode:
- 2015JMagR.250...29S
- Keywords:
-
- NMR;
- nuclear magnetic resonance;
- RF;
- radio-frequency;
- MRI;
- magnetic resonance imaging;
- CEST;
- chemical exchange saturation transfer;
- DEST;
- dark-state exchange saturation transfer;
- I;
- spin quantum number;
- RDC;
- residual dipolar coupling;
- IST;
- irreducible spherical tensor;
- J-coupling;
- scalar coupling;
- DD-coupling;
- dipole-dipole coupling;
- MCMC;
- Markov chain Monte Carlo