Mixture analysis is crucial in many areas of chemistry, and a wide variety of separation methods are in use. A common method for physical separation is high-performance liquid chromatography (HPLC), but resolution is a problem: chemically similar species coelute. An alternative approach is diffusion-ordered NMR spectroscopy (DOSY), in which the signals of mixture components are separated according to the diffusion coefficient. Again, separation is limited if species diffuse similarly or have overlap in their NMR spectra. Using the two techniques in combination can resolve both NMR spectra and the elution profiles of individual components, even where both techniques fail when used in isolation. Recording diffusion NMR data as a function of HPLC retention time gives a three-dimensional (3D) data set that can be analyzed using multiway statistical methods. PARAFAC analysis of diffusion NMR data measured from HPLC eluate for commercial “monoacetin” (a mixture of glycerol and its mono-, di-, and triacetates) yielded fully resolved and quantitative NMR spectra and elution profiles for all four components, whereas neither HPLC nor diffusion NMR applied independently was able to resolve the components.

中文翻译：

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超越 HPLC 和扩散 NMR 中的分辨率限制


混合物分析在化学的许多领域都至关重要，并且正在使用多种分离方法。一种常见的物理分离方法是高效液相色谱 （HPLC），但分离度是一个问题：化学相似的物质共洗脱。另一种方法是扩散有序 NMR 波谱 （DOSY），其中混合物组分的信号根据扩散系数分离。同样，如果物质的扩散相似或在其 NMR 波谱中有重叠，则分离会受到限制。将这两种技术结合使用可以同时解析 NMR 波谱和单个组分的洗脱曲线，即使两种技术在单独使用时都失败。将扩散 NMR 数据记录为 HPLC 保留时间的函数，可得到一个可以使用多路统计方法进行分析的三维 （3D） 数据集。PARAFAC 分析了从 HPLC 洗脱液中测量的商业“单乙酸甘油”（甘油及其单乙酸酯、双乙酸酯和三乙酸酯的混合物）的扩散 NMR 数据，得出了所有四种组分的完全分辨和定量 NMR 波谱和洗脱曲线，而独立应用的 HPLC 和扩散 NMR 都无法分辨这些组分。