A procedure for obtaining pure absorption 2D J-spectra: Application to quantitative fully J-decoupled homonuclear NMR spectra

The phase-twisted lines, resulting from a double complex Fourier transform, can greatly alter the quality of two-dimensional spectra. This problem, wh ich is generally overcome by experimental procedures (requiring twice as mu ch time as a standard measurement), is inevitable in the two-dimensional J- resolved experiment. This experiment is revisited theoretically and a postp rocessing treatment, leading to pure 2D J-spectra, is deduced. Quantitative fully J-decoupled homonuclear spectra are accordingly obtained by means of a projection onto the F2 axis after a 45 degrees tilt. (C) 1999 Academic P ress.