Chapter 7 One-dimensional TOCSY and related 1D techniques

Abstract

Publisher Summary This chapter discusses the one-dimensional (1-D) TOCSY (TOtal Correlation SpectroscopY) experiment, which, together with 1-D nuclear Overhauser enhancement spectroscopy (NOESY), is probably the most frequently and routinely used selective 1-D experiment for elucidating the spin–spin coupling network, and obtaining homonuclear coupling constants. It reviews the development of this technique and the essential features of the pulse sequence. It also discusses the practical aspects of this experiment, including the choice of the selective one (shaped) pulse, the phase difference of the hard and soft pulses, and the use of the z-filter. The application of the 1-D TOCSY pulse sequence is illustrated by examples in oligosaccharides, peptides, and mixtures. Modifications and extensions of the basic 1-D total correlation spectroscopy (TOCSY) experiment and their applications are also reviewed. As most of the applications of the 1-D TOCSY technique to date did not utilize pulsed field gradients (PFG) in the pulse sequence, the chapter discusses the nongradient versions of the 1-D TOCSY pulse sequence. The PFG versions are also discussed. In the Bax version of the pulse sequence, the selective excitation is achieved by a selective 180° pulse followed immediately by a nonselective 90° pulse to create the transverse magnetization. The difference free induction decay (FID) is then obtained from the FID with the selective 180° pulse on-resonance minus the FID obtained with the selective excitation off-resonance.