PANSY-TOCSY

Fig. 5 PANSY-TOCSY pulse sequence for simultaneous acquisition of two-dimensional H-C HETCOR and H-H TOCSY spectra...

J-splittings are only present in the C-13 detected spectra. Not only do J-splittings reduce the intensity of the correlation peaks and make the spectra more crowded and difficult to analyse, but such splittings often introduce severe overlap problems. Therefore decoupling A and X spins is generally desirable. This is easily achieved by displacing the A and X acquisition periods. The 2D H-C PANSY TOCSY experiment shown in Fig. 5 does just that. 

Fig. 6 Two-dimtaisi

An example of the Hadamard encoded PANSY-TOCSY pulse sequence is shown in Fig. 18. The conventional free evolution is replaced with a Hadamard encoding pulse as can be appreciated by comparing Figs. 17 and 5. The PANSY-TOCSY spectra of inosine recorded with Hadamard encoding in just 22 s are shown in Fig. 19. 

Fig. 18 PANSY-TOCSY pulse sequence with Hadamard encoding (to be compared with the conventional pulse sequence shown in Fig. 5)...

Fig. 19 Hadamard PANSY-TOCSY spectra of inosine recorded in 22 s using Hadamard encoding. A Varian 600 MHz system equipped with two receivers and a cryogenic HCN probe that is optimized for C-13 detection were used. The pulse sequence is shown in Fig. 17. Reproduced from Ref. 27. The American Chemical Society, 2006...

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