NMR Basics

NMR Spectroscopy Principles, Interpreting an NMR Spectrum and Common Problems Link || Keeler Lectures

Typical NMR questions Link Link-II

LipSpin: A New Bioinformatics Tool for Quantitative ¹H NMR Lipid Profiling link Link2

A comprehensive discussion of HSQC and HMQC pulse sequences Link

NMR Course Lecture Series by J Keeler: Youtube

Brief About NMR Spectroscopy: Youtube

Biomolecular NMR spectroscopy in the era of artificial intelligence Link

NMR Box Link

NMR spectra processing for everybody Link

NMR Relaxation Explained pictorially Link

NMRS 2024 at CBMR Link

Principal of quadrature detection in NMR explained schematically:

Fourier Transformation of Generic NMR Signal

Effect of Radiofrequency (RF) pulse on nuclear spin magnetization

Simple spin-echo sequences and Chemical shift evolution

Spin echo allows the transverse relaxation to happen (e.g. we see T2 filtering in CPMG NMR experiments)

However, spin-echo refocuses the local magnetic field inhomogeneities as depicted below through vector transformations

NMR signal splitting under J-coupling explained pictorially

For AX spin system

For AX2 Spin system:

Product operator formulism: Evolution under J-coupling

The simple rules of evolution under J-coupling are depicted here:

Let us see how spins evolve during INEPT Sequence (only J-evolution is performed as spin-echo will refocus the 1H chemical shift). INEPT stands for Insensitive nuclei enhancement through polarization transfer

After INEPT, the magnetization is 2HzCy (antiphase). The refocused INEPT sequence produces in-phase magnetization Cx suitable for 1H decoupling to produce high intensity singlet peaks.