Abstract: An NMR spectroscopy method monitors a component of a sample, the component having two resonances in coupled together different spectral regions. The first resonance lies in a region including a resonance of a second component of a sample while the second resonance lies in a spectral region including a resonance of a third component of the sample. Two spin-echo pulse sequences each consisting of pulses of a predetermined frequency are applied, the spin-echo resonance spectra together being used to obtain the second resonance of the first component with the resonance of the third component suppressed.

Abstract: In a method of high resolution pulsed NMR spectroscopy, the r.f. field is deliberately made inhomogeneous and a special pulse sequence is used to ensure that the received signals emanate predominantly from a selected region of the sample. Thus, the acquisition pulse (70) from which the FID signal (72) results is preceded by a preparatory treatment involving at least one r.f. pulse (66) which is a 180.degree. pulse in respect of nuclei of interest in the selected region, preferably followed by a d.c. pulse (68) giving rise to a magnetic field gradient superimposed on the main alignment field.