Hamed Nouran A, Shread Alexandria K, Morris Gareth A, Nilsson Mathias
Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom.
Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Tanta University, Tanta 31111, Egypt.
Anal Chem. 2024 Dec 31;96(52):20475-20480. doi: 10.1021/acs.analchem.4c04418. Epub 2024 Dec 18.
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.
混合物分析在化学的许多领域都至关重要，并且有各种各样的分离方法正在使用。物理分离的一种常用方法是高效液相色谱法（HPLC），但分辨率是个问题：化学性质相似的物质会同时洗脱。另一种方法是扩散排序核磁共振光谱法（DOSY），其中混合物成分的信号根据扩散系数进行分离。同样，如果物质扩散相似或在核磁共振光谱中有重叠，分离就会受到限制。将这两种技术结合使用可以解析核磁共振光谱以及各个成分的洗脱曲线，即使在单独使用这两种技术时都会失败的情况下也是如此。将扩散核磁共振数据记录为HPLC保留时间的函数会得到一个三维（3D）数据集，可以使用多向统计方法进行分析。对从商业“单乙酸甘油酯”（甘油及其单、二、三乙酸酯的混合物）的HPLC洗脱液中测得的扩散核磁共振数据进行PARAFAC分析，得到了所有四种成分的完全解析且定量的核磁共振光谱和洗脱曲线，而单独应用HPLC或扩散核磁共振都无法解析这些成分。
