title: Ultrafast double-quantum NMR spectroscopy with optimized sensitivity for the analysis of mixtures.
abstract: Ultrafast (UF) 2D NMR enables the acquisition of 2D spectra within a single-scan. This methodology has become a powerful analytical tool, used in a large array of applications. However, UF NMR spectroscopy still suffers from the need to compromise between sensitivity, spectral width and resolution. With the commonly used UF-COSY pulse sequence, resolution issues are compounded by the presence of strong auto-correlation signals, particularly in the case of samples with high dynamic ranges. The recently proposed concept of UF Double Quantum Spectroscopy (DQS) allows a better peak separation as it provides a lower spectral peak density. This paper presents the detailed investigation of this new NMR tool in an analytical chemistry context. Theoretical calculations and numerical simulations are used to characterize the modulation of peak intensities as a function of pulse-sequence parameters, and thus enable a significant enhancement of the sensitivity. The analytical comparison of UF-COSY and UF-DQS shows similar performances, however the ultrafast implementation of the DQS approach is found to have some sensitivity advantages over its conventional counterpart. The analytical performance of the pulse sequence is illustrated by the quantification of taurine in complex mixtures (homemade and commercial energy drinks). The results demonstrate the high potential of this experiment, which forms a valuable alternative to UF-COSY spectra when the latter are characterized by strong overlaps and high dynamic ranges.
authors: Université de Nantes, UMR CNRS 6230 CEISAM, Nantes, France. patrick.giraudeau@univ-nantes.fr and MFP Michelin, Clermont-Ferrand, France.
authors: Laetitia
authors: L
authors: Rouger
authors: Université de Nantes, UMR CNRS 6230 CEISAM, Nantes, France. patrick.giraudeau@univ-nantes.fr.
authors: Boris
authors: B
authors: Gouilleux
authors: Université de Nantes, UMR CNRS 6230 CEISAM, Nantes, France. patrick.giraudeau@univ-nantes.fr.
authors: Mariane
authors: M
authors: Pourchet-Gellez
authors: Institut de Chimie des Substances Naturelles, CNRS UPR2301, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France. jeannicolas.dumez@cnrs.fr.
authors: Jean-Nicolas
authors: JN
authors: Dumez
authors: Université de Nantes, UMR CNRS 6230 CEISAM, Nantes, France. patrick.giraudeau@univ-nantes.fr and Institut Universitaire de France, Paris, France.
authors: Patrick
authors: P
authors: Giraudeau