IMPROVED J-COMPENSATED APT EXPERIMENTS

The derivation and investigation of two new J-compensated attached-proton-test experiments, CAPT2 and CAPT3, are presented. These methods incorporate fewer pulses than CAPT and are shown to be more effective over a wider range of 1JCH than spin flip, APT, and CAPT for CH, CH2, and CH3 spin systems. In addition, the magnitude of the flip angle of the initial pulse which creates transverse carbon magnetization is unrestricted in CAPT2 and CAPT3. The compensated CAPT3 sequence, which is patterned after the 90°x90°y90°x composite pulse, is found to be excellent for routine use in 13C spectroscopy. © 1993 by Academic Press, Inc.