Rouger Laetitia, Gouilleux Boris, Pourchet-Gellez Mariane, Dumez Jean-Nicolas, Giraudeau Patrick
Université de Nantes, UMR CNRS 6230 CEISAM, Nantes, France.
Institut de Chimie des Substances Naturelles, CNRS UPR2301, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France.
Analyst. 2016 Mar 7;141(5):1686-92. doi: 10.1039/c6an00089d.
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.
超快（UF）二维核磁共振（NMR）能够在单次扫描内获取二维谱图。这种方法已成为一种强大的分析工具，应用于大量领域。然而，超快核磁共振光谱法仍需在灵敏度、谱宽和分辨率之间做出妥协。对于常用的超快相关谱（UF-COSY）脉冲序列，强自相关信号的存在会使分辨率问题更加复杂，尤其是在动态范围较大的样品中。最近提出的超快双量子光谱学（DQS）概念能够实现更好的峰分离，因为它提供了更低的谱峰密度。本文在分析化学背景下对这种新的核磁共振工具进行了详细研究。通过理论计算和数值模拟来表征峰强度随脉冲序列参数的变化，从而显著提高灵敏度。超快相关谱（UF-COSY）和超快双量子光谱学（UF-DQS）的分析比较显示出相似的性能，然而发现超快双量子光谱学（DQS）方法的超快实现形式相对于传统形式具有一些灵敏度优势。通过对复杂混合物（自制和市售能量饮料）中的牛磺酸进行定量，说明了该脉冲序列的分析性能。结果表明该实验具有很大潜力，当超快相关谱（UF-COSY）谱图存在强重叠和高动态范围时，它是超快相关谱（UF-COSY）谱图的一种有价值的替代方法。
