J‐filter: An experiment to simplify and isolate specific signals in 1 H NMR spectra of complex mixtures based on scalar coupling constants

One‐dimensional selective NMR experiments relying on a J‐filter element are proposed to isolate specific signals in crowded 1 H spectral regions. The J‐filter allows the edition or filtering of signals in a region of interest of the spectrum by exploiting the specific values of their 1 H‐ 1 H coupling constants and certain parameters of protons coupled to them that appear in less congested parts of the spectrum (chemical shifts and coupling constants). The new experiments permitted the isolation of specific peaks of phytosterol components in a sample obtained from a liquid nutraceutical recommended for lowering blood cholesterol levels in regions with complete overlap in the 1 H spectrum.