Related Experiment Video
Updated: Jul 3, 2026
13:16
Pure Shift Nuclear Magnetic Resonance: a New Tool for Plant Metabolomics
Published on: July 31, 2021
Chemical shift correlations from hyperpolarized NMR by off-resonance decoupling
Sean Bowen1, Haifeng Zeng, Christian Hilty
1Texas A&M University, Chemistry Department, 3255 TAMU, College Station, Texas 77843, USA.
Analytical Chemistry
|July 9, 2008
Summary
Dynamic nuclear polarization significantly enhances Nuclear Magnetic Resonance (NMR) signals. This study presents a method for rapid 2D chemical shift correlations in hyperpolarized molecules, simplifying molecular structure analysis.
Area of Science:
- Chemistry
- Spectroscopy
- Biophysics
Background:
- Nuclear Magnetic Resonance (NMR) spectroscopy provides detailed molecular structure information via chemical shifts and correlations.
- Traditional NMR is limited by low sensitivity, requiring high concentrations and long acquisition times.
- Dynamic nuclear polarization (DNP) hyperpolarization can amplify NMR signals by orders of magnitude.
Purpose of the Study:
- To present a robust method for recording 2D chemical shift correlations from hyperpolarized molecules.
- To enable faster and more sensitive NMR analyses of molecular structures.
- To facilitate routine application of advanced NMR techniques.
Main Methods:
- Utilizing dynamic nuclear polarization (DNP) to hyperpolarize samples.
- Applying an off-resonance decoupling field to scale observed scalar couplings.
- Recording 2D chemical shift correlation spectra from hyperpolarized samples.
Main Results:
- Successfully recorded 2D chemical shift correlations from hyperpolarized molecules.
- Demonstrated that the method allows direct reading of correlations from a small number of scans.
- Showcased the technique's applicability for carbon-proton chemical shift correlations in organic molecules.
Conclusions:
- The presented method offers a robust way to obtain 2D NMR chemical shift correlations from hyperpolarized samples.
- The technique's ease of implementation on commercial equipment makes it suitable for routine use.
- This advancement significantly improves the sensitivity and speed of NMR-based molecular structure determination.
Related Concept Videos
01:04¹³C NMR: ¹H–¹³C Decoupling
The probability of having two carbon-13 atoms next to each other is negligible because of the low natural abundance of carbon-13. Consequently, peak splitting due to carbon-carbon spin-spin coupling is not observed in spectra. However, protons up to three sigma bonds away split the carbon signal according to the n+1 rule, resulting in complicated spectra.
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
01:20¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)
When proton-coupled carbon-13 spectra are simplified by a broadband proton decoupling technique, structural information about the coupled protons is lost. Distortionless enhancement by polarization transfer (DEPT) is a technique that provides information on the number of hydrogens attached to each carbon in a molecule. While the DEPT experiment utilizes complex pulse sequences, the pulse delay and flip angle are specifically manipulated. The resulting signals have different phases depending on...
01:182D NMR: Overview of Heteronuclear Correlation Techniques
Heteronuclear correlation spectroscopy is an analytical technique that investigates the coupling between different types of nuclei, often a proton and an X-nucleus, such as carbon-13 or nitrogen-15. This method is commonly used in nuclear magnetic resonance (NMR) spectroscopy to gain insights into complex chemical compounds' structural and compositional aspects. A typical heteronuclear correlation spectrum displays X-nucleus chemical shifts on one axis and a proton spectrum on the other axis.
01:02¹H NMR: Interpreting Distorted and Overlapping Signals
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 slanted or...
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 slanted or...
01:12Double Resonance Techniques: Overview
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...
01:192D NMR: Heteronuclear Single-Quantum Correlation Spectroscopy (HSQC)
Heteronuclear single-quantum correlation spectroscopy (HSQC) is a 2D NMR technique that reveals one-bond correlations between hydrogen and a heteronucleus. The HSQC experiment is similar to the heteronuclear correlation experiment (HETCOR) but is more sensitive. In the HSQC spectrum, the proton chemical shift is plotted on the horizontal F2 axis, while the 13C chemical shift is plotted on the vertical F1 axis. The corresponding proton and 13C spectra are also shown. The HSQC contour plot does...