On the spin order transfer from parahydrogen to another nucleus
On the spin order transfer from parahydrogen to another nucleus
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DOI：
10.1016/j.jmr.2012.08.016
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发表时间：
2012-12-01
影响因子：
2.2
通讯作者：
Hoevener, Jan-Bernd
中科院分区：
文献类型：
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作者：
Baer, Sebastien;Lange, Thomas;Hoevener, Jan-Bernd
核自旋的超极化具有巨大的潜力，例如在生物医学研究方面。例如，通过自旋-顺序转移(SOT)序列将对氢(pH(2))的自旋顺序转变为第三核(例如C-13)的净极化，已经证明了强信号增强。实现的极化与序列间隔密切相关，序列间隔是要极化的分子的J耦合常数的函数。然而，如何推导SOT序列间隔、分子的实际值以及(理论)极化产额和稳健性并没有完全描述。在本文中，(A)我们提供了获得一组给定J耦合常数(即新的超极化试剂)的SOT间隔的方法；(B)用文献中的分子举例说明了这些方法，提供了迄今缺失的间隔和模拟的极化产额；以及(C)评估了序列对B-1和J耦合误差的稳健性。对于所有的分子和序列，都获得了接近单位的极化。此外，通过适当地选择SOT序列中某些脉冲的通道和相位，减小了由错误的B-1和J耦合常数引起的偏振损失。(C)2012 Elsevier Inc.保留所有权利。
The hyperpolarization of nuclear spins holds great potential e.g. for biomedical research. Strong signal enhancements have been demonstrated e.g. by transforming the spin order of parahydrogen (pH(2)) to net polarization of a third nucleus (e.g. C-13) by means of a spin-order-transfer (SOT) sequence. The polarization achieved is vitally dependent on the sequence intervals, which are a function of the J-coupling constants of the molecule to be polarized. How to derive the SOT sequence intervals, the actual values for molecules as well as the (theoretical) polarization yield and robustness, however, are not fully described. In this paper, (a) we provide the methods to obtain the SOT intervals for a given set of J-coupling constants (i.e. of a new hyperpolarization agent); (b) exemplify these methods on molecules from literature, providing the hitherto missing intervals and simulated polarization yield; and (c) assess the robustness of the sequences towards B-1 and J-coupling errors. Close to unity polarization is obtained for all molecules and sequences. Furthermore, the loss of polarization caused by erroneous B-1 and J-coupling constants is reduced by choosing the channel and phase of some pulses in the SOT sequences appropriately. (C) 2012 Elsevier Inc. All rights reserved.