A new pulse sequence is proposed for extracting subspectra of individual components of sugar chains. The method uses a combination of the MMDY composite pulse and the double pulsed field gradient spin-echo and is shown to be useful in the analysis of complex spectra with many overlapped signals. The main advantages of this method are: (i) a significant decrease in experiment acquisition times; (ii) the magnetization transfer is especially efficient, for example, for sugar residues such as Ara and Rha, which have one of the coupling of ca. 1 Hz around the sugar rings, complete subspectra can be quickly obtained; (iii) high-quality pure-absorption phase subspectra can be recorded without the use of the Z-filter technique; (iv) since the gradients merely serve to suppress unwanted signals, they are not subject to the sensitivity losses associated with gradient coherence pathway selection. Its application to the separation of severely overlapping spin systems is illustrated using glycoside sample.

Key words: NMR, MMDY composite pulse, structural determination of oligosaccharide chain