The hyperfine structure of glycolaldehyde and 1,3-dihydroxyacetone has been observed using high-resolution microwave Fourier transform spectroscopy. The nuclear spin-rotation interaction was evaluated ab initio at the B3LYP/aug-cc-pVTZ level of the theory using the B3LYP/6-311++G(d, p) molecular structure, and was found to be negligible. Using a suitable Hamiltonian model, the nuclear spin-spin coupling tensor was determined from the molecular structure and from the experimental spectrum. The model developed for the smallest aldose and ketose can be extended to any sugar. (c) 2006 Elsevier B.V. All rights reserved.