Toward Nanomolar Detection by NMR Through SABRE Hyperpolarization
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- 作者：Nan Eshuis ; Niels Hermkens ; Bram J. A. van Weerdenburg ; Martin C. Feiters ; Floris P. J. T. Rutjes ; Sybren S. Wijmenga ; Marco Tessari
- 刊名：Journal of the American Chemical Society
- 出版年：2014
- 出版时间：February 19, 2014
- 年：2014
- 卷：136
- 期：7
- 页码：2695-2698
- 全文大小：265K
- ISSN：1520-5126
文摘
SABRE is a nuclear spin hyperpolarization technique based on the reversible association of a substrate molecule and para-hydrogen (p-H2) to a metal complex. During the lifetime of such a complex, generally fractions of a second, the spin order of p-H2 is transferred to the nuclear spins of the substrate molecule via a transient scalar coupling network, resulting in strongly enhanced NMR signals. This technique is generally applied at relatively high concentrations (mM), in large excess of substrate with respect to metal complex. Dilution of substrate ligands below stoichiometry results in progressive decrease of signal enhancement, which precludes the direct application of SABRE to the NMR analysis of low concentration (渭M) solutions. Here, we show that the efficiency of SABRE at low substrate concentrations can be restored by addition of a suitable coordinating ligand to the solution. The proposed method allowed NMR detection below 1 渭M in a single scan.