THEORETICAL AND EXPERIMENTAL APT AND DEFT BEHAVIOR OF METHANE

The theoretically developed Attached Proton Test (APT) and Distortionl ess Enhancement by Polarization Transfer (DEFT) curves for methane wer e compared with the corresponding experimentally measured data for C-1 3 enriched methane. As expected, in both cases the CH4 curves have a s imilar shape than the corresponding CH2 curves and show a minimum inte nsity when tau = 1/2J. In the APT case the CH2 curve takes larger valu es than the CH4 curve except at tau = 0, 1/2J and 1/J values where the y have the same intensity. In the DEFT experiment, the maximum polariz ation transfer for CH4 takes place at tau = 1/6J and 5/6J, while for C H2 this happen at tau = 1/4J and 3/4J. This fact could be useful to di stinguish the CH2 and CH4 signals using APT and DEFT experiments.