Abstract
A NMR method based on the combination of selective pulses with Zero-Quantum Filtered TOCSY magnetization transfer was used to measure the specific 13C-enrichment of labelled molecules. The analysis of a labelled lysine sample showed that DANTE-Z schemes give accurate measurements; meanwhile, DPFGSE schemes resulted in the underestimation of 13C-enrichments. The former method can be applied to overcome signal overlap problems that are often encountered in the analysis of labelled molecules.