Universally quantitative band-selective pure shift NMR spectroscopy

NMR spectroscopy is often described as a quantitative analytical technique. Strictly, only the simple pulse-acquire experiment is universally quantitative, but the poor signal resolution of the ¹H NMR pulse-acquire experiment frequently complicates quantitative analysis. Pure shift NMR techniques provide higher resolution, by reducing signal overlap, but they are susceptible to a variety of sources of site-dependent signal loss. Here, we introduce a new method that corrects for signal loss from such sources in band-selective pure shift NMR experiments, by performing different numbers of iterations of the same pulse sequence elements before acquisition to allow extrapolation back to the loss-free signal. We apply this method to both interferogram and semi-real-time acquisition modes, obtaining integrals within 1 % of those acquired from a pulse-acquire experiment for a three-component mixture.

核磁共振波谱法（NMR spectroscopy）常被视为一种定量分析技术。严格来说，仅简单脉冲采集实验（simple pulse-acquire experiment）具备普适性的定量特性，但氢-1（¹H）核磁共振脉冲采集实验的信号分辨率较差，常使定量分析变得复杂。纯位移核磁共振技术（Pure shift NMR techniques）通过抑制信号重叠可获得更高分辨率，但这类技术易受多种位点依赖性信号损耗因素的影响。本文提出一种新方法，可在带选择性纯位移核磁共振实验中校正此类信号损耗：通过在采集前对相同脉冲序列单元执行不同次数的迭代，实现外推至无损耗信号。我们将该方法应用于干涉图与半实时采集两种模式，针对三组分混合物得到的积分强度与脉冲采集实验的结果偏差在1%以内。