NMR-Based Chemosensing via p-H2 Hyperpolarization: Application to Natural Extracts

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• 作者：Niels K. J. Hermkens ; Nan Eshuis ; Bram J. A. van Weerdenburg ; Martin C. Feiters ; Floris P. J. T. Rutjes ; Sybren S. Wijmenga ; Marco Tessari
• 刊名：Analytical Chemistry
• 出版年：2016
• 出版时间：March 15, 2016
• 年：2016
• 卷：88
• 期：6
• 页码：3406-3412
• 全文大小：441K
• ISSN：1520-6882

文摘

When dealing with trace analysis of complex mixtures, NMR suffers from both low sensitivity and signal overlap. NMR chemosensing, in which the association between an analyte and a receptor is “signaled” by an NMR response, has been proposed as a valuable analytical tool for biofluids and natural extracts. Such chemosensors offer the possibility to simultaneously detect and distinguish different analytes in solution, which makes them particularly suitable for analytical applications on complex mixtures. In this study, we have combined NMR chemosensing with nuclear spin hyperpolarization. This was realized using an iridium complex as a receptor in the presence of parahydrogen: association of the target analytes to the metal center results in approximately 1000-fold enhancement of the NMR response. This amplification allows the detection, identification, and quantification of analytes at low-micromolar concentrations, provided they can weakly associate to the iridium chemosensor. Here, our NMR chemosensing approach was applied to the quantitative determination of several flavor components in methanol extracts of ground coffee.