THE ACCORDION APPROACH FOR TAYLORED TOCSY

In a recent publication (J. Magn. Reson. A, 114, 188 (1995)) a method, called ''Taylored TOCSY,'' was introduced. This method makes it possible to identify the number of successive couplings which give rise to each cross peak in a TOCSY spectrum. The method involves recording a series of TOCSY spectra with increasing mixing times and then analyzing the way in which the intensity of the cross peaks varies with mixing time. The need to record several complete TOCSY spectra is a disadvantage of the method, In this paper, it is shown that, in some circumstances, accordion spectroscopy provides a convenient alternative way of acquiring the data needed for the Taylored TOCSY analysis. In accordion spectroscopy, the mixing time is incremented in concert with t(1), thus transferring the information about the buildup of the cross-peak intensity to the lineshape in the F-1 dimension. The buildup curve can, in principle, be derived from a single accordion-TOCSY experiment. The basic theory of this method is described and the issues involved in its practical implementation are discussed; experimental data illustrating the use of the method are also presented. (C) 1995 Academic Press, Inc.