| 利用相位步进脉冲消除探头13C NMR背景信号 |
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| 引用本文： | 魏令,张善民.利用相位步进脉冲消除探头13C NMR背景信号[J].波谱学杂志,2020,37(1):123-130. |
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| 作者姓名： | 魏令 张善民 |
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| 作者单位： | 1. 重质油国家重点实验室, 中国石油大学(华东) 化学工程学院, 山东 青岛 266580;2. 上海市磁共振重点实验室, 华东师范大学 物理与材料科学学院, 上海 200062 |
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| 基金项目： | 国家自然科学基金资助项目（21604094）. |
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| 摘 要： | 由静态探头线圈外有机材料产生的13C NMR背景信号强度大，化学位移范围广（δC 20~250），此背景信号在交叉极化实验中还可被增强，并随着样品信号的累积而累积，严重影响谱图分析.将相位步进脉冲引入交叉极化实验（称为PIPCP）中可以有效去除经交叉极化增强的13C NMR背景信号，但样品信号不受影响.这是由于经过相位步进脉冲后，线圈外相位严重畸变，而且线圈外锁定场强度急剧降低，来自探头材料的13C NMR背景信号无法有效地进行交叉极化.而对于被测样品甘氨酸来说，由于I核和S核之间强烈的偶极耦合作用，所加相位步进脉冲对锁定场强度的影响只有1.4%.
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| 关 键 词： | 固体核磁共振 背景信号消除 相位步进脉冲 交叉极化 |
| 收稿时间： | 2019-04-17 |
Suppressing Background 13C NMR Signal From the Probe Head by Phase Incremented Pulses |
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| WEI Ling,ZHANG Shan-min.Suppressing Background 13C NMR Signal From the Probe Head by Phase Incremented Pulses[J].Chinese Journal of Magnetic Resonance,2020,37(1):123-130. |
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| Authors: | WEI Ling ZHANG Shan-min |
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| Institution: | 1. State Key Laboratory of Heavy Oil Processing & College of Chemical Engineering, China University of Petroleum(East China), Qingdao 266580, China;2. Shanghai Key Laboratory of Magnetic Resonance, College of Physics and Materials Science, East China Normal University, Shanghai 200062, China |
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| Abstract: | The background 13C NMR signal originated from the organic materials in the probe head cross-polarizes from 1H nucleus to 13C nucleus. This background 13C NMR signal is very broad (δC 20~250) and accumulates as the sample signal accumulating. Hartman-Hahn cross polarization with phase-incremented pulses in the S spin channel (denoted as PIPCP) is developed to suppress this background signal. The application of PIPCP results in severe phase distortion outside the radio frequency coil such that the background 13C NMR signal cannot cross polarize and thus be suppressed. In comparison, depending on the dipolar coupling constant between 1H and 13C nuclei, PIPCP induces only a small amount of Hartman-Hahn mismatch (1.4%) to the desired signals. |
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| Keywords: | solid-state nuclear magnetic resonance background signal suppression phase incremented pulses cross polarization |
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