A method of time domain deconvolution, QUALITY, is described for general use in quantitative NMR spectroscopy. By division of the experimental NMR time domain signal by a reference signal, which may be obtained either in a separate experiment or via inverse Fourier transformation of an isolated single resonance in the experimental spectrum, perfect Lorentzian lineshapes can be obtained regardless of the magnetic field inhomogeneity. Experiments, both in vivo using a surface coil and in vitro using a surface coil and a HR NMR probe, show excellent performance of the method.