Fast and precise quantitative analysis of metabolic mixtures by 2D 1H INADEQUATE NMR

Quantitative analysis of metabolic mixtures by H-1 1D NMR offers a limited potential for precise quantification of biomarkers, due to strong overlap between the peaks. Two-dimensional spectroscopy is a powerful tool to unambiguously and simultaneously measure a larger number of metabolite contributions. However, it is still rarely used for quantification, first because quantitative analysis by 2D NMR requires a calibration procedure due to the multi-impulsional nature of 2D NMR experiments, and above all because of the prohibitive experiment duration that is necessary to obtain such a calibration curve. In this work, we develop and evaluate a 2D H-1 INADEQUATE protocol for a fast determination of metabolite concentrations in complex mixtures. The 2D pulse sequence is carefully optimized and evaluated in terms of precision and linearity. Quantitative H-1 INADEQUATE 2D spectra of metabolic mixtures are obtained in 7 min with a repeatability better than 2% for metabolite concentrations as small as 100 mu M and an excellent linearity. The method described in this work allows a fast and precise quantification of metabolic mixtures, and it forms a promising tool for metabonomic studies. (c) 2010 Elsevier B.V. All rights reserved.