通过粒子介导交叉放松来实现通用化溶液状态H DNP NMR
Sungsool Wi1, Angeliki Giannouli2, Korin Butbul2
1National High Magnetic Field Laboratory, Tallahassee, Florida 32304, United States.
The journal of physical chemistry letters
|June 20, 2025
概括
这项研究展示了一种新方法,用于在小型液体样本上使用动态核极化 (DNP) 来增强质子核磁共振 (NMR) 信号. 该技术通过将偏振从固体粒子转移到液体相来增强信号.
科学领域:
- 磁共振光谱学 磁共振光谱学
- 物理化学 物理化学
- 材料科学 材料科学 材料科学
背景情况:
- 在高磁场下增强低体积液相H NMR信号是具有挑战性的.
- 动态核极化 (DNP) 提供了信号增强的途径,但通常需要冷温度或特定的样本条件.
- 当前的DNP方法可能与高分辨率NMR要求或标准样本体积不兼容.
研究的目的:
- 研究一种基于DNP的新方法,用于在小液体体积 (100μL尺度) 中增强H NMR信号.
- 为了在使用粒子介导极化转移的非热温度下实现信号增强.
- 探索这种方法在高分辨率NMR应用中的可行性.
主要方法:
- 在液体样本 (heptane) 中分散富含质子,DNP活性BDPA合的聚乙烯 (PS) 微粒.
- 固态DNP增强PS质子在14.1 T和185-220 K使用395 GHz微波辐射.
- 测量液相HNMR信号增强通过从极化固体粒子的交叉放松.
主要成果:
- 在2秒内实现了PS质子极化的12倍增强.
- 观察到DNP6秒后的赫普坦质子共振大约增强了3倍,保持了窄线宽度 (≤2Hz).
- 优化条件使用化PS/PS/BDPA粉末悬浮在失去化赫中-d16获得最佳结果.
结论:
- 证明了一种可行的粒子介导的DNP方法,用于在高电场下增强液相H NMR信号.
- 该方法允许信号增强而不影响样本体积,高分辨率条件或多扫描平均值.
- 这种技术为未来的DNP增强型NMR应用提供了可通用的策略.
相关概念视频
Atomic Nuclei: Types of Nuclear Relaxation
399
Nuclear relaxation restores the equilibrium population imbalance and can occur via spin–lattice or spin–spin mechanisms, which are first-order exponential decay processes.
In spin–lattice or longitudinal relaxation, the excited spins exchange energy with the surrounding lattice as they return to the lower energy level. Among several mechanisms that contribute to spin–lattice relaxation, magnetic dipolar interactions are significant. Here, the excited nucleus transfers...
In spin–lattice or longitudinal relaxation, the excited spins exchange energy with the surrounding lattice as they return to the lower energy level. Among several mechanisms that contribute to spin–lattice relaxation, magnetic dipolar interactions are significant. Here, the excited nucleus transfers...
399
¹H NMR: Interpreting Distorted and Overlapping Signals
1.1K
Spin systems where the difference in chemical shifts of the coupled nuclei is greater than ten times J are called first-order spin systems. These nuclei are weakly coupled, and their chemical shifts and coupling constant can generally be estimated from the well-separated signals in the spectrum.
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
1.1K
2D NMR: Overview of Homonuclear Correlation Techniques
302
Homonuclear correlation spectroscopy (COSY) is a powerful technique used in Nuclear Magnetic Resonance (NMR) spectroscopy to study the correlations between nuclei of the same type within a molecule. It provides information about scalar couplings between adjacent nuclei, which helps determine connectivity and structural information. There are several COSY variants, each with its unique strengths and experimental parameters.
COSY90 is the standard two-dimensional (2D) COSY experiment that...
COSY90 is the standard two-dimensional (2D) COSY experiment that...
302
¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
924
At room temperature, the chair conformer of cyclohexane undergoes rapid ring flipping between two equivalent chair conformers at a rate of approximately 105 times per second. These two chair conformers are in equilibrium. The rapid ring flipping results in the interconversion of the axial proton to an equatorial proton and an equatorial to the axial proton. Such interconversions are too rapid and cannot be detected on the NMR timescale. Hence, the NMR spectrometer cannot distinguish between the...
924
Double Resonance Techniques: Overview
310
Double resonance techniques in Nuclear Magnetic Resonance (NMR) spectroscopy involve the simultaneous application of two different frequencies or radiofrequency pulses to manipulate and observe two distinct nuclear spins. One important application of double resonance is spin decoupling, which selectively suppresses coupling with one type of nucleus while observing the NMR signal from another nucleus, simplifying the spectrum and enhancing resolution.
Spin decoupling is usually achieved by...
Spin decoupling is usually achieved by...
310
Interpreting ¹H NMR Signal Splitting: The (n + 1) Rule
1.5K
In the AX proton spin system, proton A can sense the two spin states of a coupled proton X, resulting in a doublet NMR signal with two peaks of equal (1:1) intensity. When proton A is coupled to two equivalent protons (AX2 spin system), the spin states of each X can be aligned with or against the external field, creating three possible scenarios. This results in a 1:2:1 triplet signal, where the central peak corresponds to the chemical shift of A and is twice as large or intense as the...
1.5K


![Measuring the Spin-Lattice Relaxation Magnetic Field Dependence of Hyperpolarized [1-13C]pyruvate](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F59399.jpg&w=3840&q=50)