A simple C-13 MAS spin-echo experiment is applied to a partially C-13-labelled cellulose sample extracted from wood. C-13-C-13 J couplings are determined even though considerable chemical disorder leads to observed linewidths in the normal 1D C-13 CP MAS spectrum which far exceed the J couplings. The fitting of the experimental data also allows the quantification of the degree of isotopic enrichment. (C) 2004 Elsevier Inc. All rights reserved.