Liquid chromatography and Raman spectroscopy (LC-Raman system) were combined and developed with the aid of the vertical flow method that enhances the Raman signal intensity. The LC-Raman system enabled the online acquisition of the nonresonance Raman spectrum of LC eluates. We employed singular value decomposition (SVD) and subsequent reconstruction of the components for the analysis of two-dimensional (temporal and spectral) data. The obtained components were consistent with the Raman spectra and elution patterns of the samples, indicating the appropriateness of the SVD-based procedure. The rise and fall times of the elution band of the temporal component were considered as the instrumental function. D₂O mixed with H₂O exhibited increased full width at half maximum of the elution band of up to 30% in comparison to the calculated value because of diffusion. Band broadening was less significant in the case in which an immiscible solute (pentane) was mixed with H₂O. The limits of detection and quantitation were 1.2 ± 0.1, 2.1 ± 0.1, and 2.7 ± 0.1 mM and 4.1 ± 0.1, 6.9 ± 0.1, and 9.1 ± 0.2 mM for the ortho-, meta-, and para-isomers of methoxyphenol, respectively. The nonresonance Raman experiment provides the molecular specificity to LC on the basis of the inherent properties of eluates.

中文翻译：

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垂直流动法在线液相色谱-拉曼光谱

液相色谱法和拉曼光谱法（LC-拉曼系统）相结合，并借助增强拉曼信号强度的垂直流方法进行了开发。LC-拉曼系统可在线获取LC洗脱液的非共振拉曼光谱。我们采用奇异值分解（SVD）并随后对这些组件进行重构，以分析二维（时间和频谱）数据。所获得的成分与样品的拉曼光谱和洗脱模式一致，表明基于SVD的程序的适当性。时间分量洗脱带的上升和下降时间被认为是工具功能。D ₂ O与H ₂混合由于扩散，与计算值相比，O在洗脱带的一半最大值处显示出增加的全宽，最高可达30％。在不溶混的溶质（戊烷）与H ₂ O混合的情况下，谱带展宽不太明显。检测和定量限为1.2±0.1、2.1±0.1和2.7±0.1 mM和4.1±0.1、6.9±甲氧基苯酚的邻，间和对位异构体分别为0.1和9.1±0.2 mM。非共振拉曼实验根据洗脱液的固有性质，提供了对LC的分子特异性。