Optimizing the INADQT experiment

CHED 837

Brandon W. Bartoskewitz and Dr. Ben Shoulders. Department of Chemistry and Biochemistry, University of Texas at Austin, 24th and Speedway, Welch Building 1.412, Austin, TX 78712
The INADQT experiment is an NMR pulse sequence that generates a Carbon-Carbon connectivity 2D spectrum. The natural abundance of 13C is only 1.1%. This results in a low sensitivity for carbon NMR. However, in the INADQT experiment, connectivity is only shown when 13C is present on each end of a Carbon-Carbon bond. The probability of this situation is only 0.01%. Thus the sensitivity of the INADQT experiment is indeed very low. In order to optimize sensitivity, the number of scans must be maximized and this requires a shorter than normal relaxation time. Several strategies for reducing this time have been investigated. Mixed solvents like DMSO and D2O, as well as relaxing reagents have been shown to be successful.