Quantitative Nuclear Magnetic Resonance Spectroscopy with Overhauser Dynamic Nuclear Polarization

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Chemical Engineering

Background:

• Nuclear magnetic resonance (NMR) spectroscopy is valuable for process monitoring but lacks sensitivity for diluted samples.
• Hyperpolarization techniques like Overhauser dynamic nuclear polarization (ODNP) can significantly enhance NMR signals.
• ODNP's application to quantitative mixture analysis has been limited due to variable signal enhancements.

Purpose of the Study:

• To address the challenge of quantitative analysis of mixtures using ODNP-enhanced NMR.
• To demonstrate the feasibility of ODNP for analyzing highly diluted components in flowing samples.
• To develop a robust calibration procedure for accurate ODNP-enhanced NMR mixture quantification.

Main Methods:

• Utilized Overhauser dynamic nuclear polarization (ODNP) with ${}^1$ H and ${}^{13}$ C NMR spectroscopy.
• Conducted continuous-flow experiments using a benchtop NMR spectrometer.
• Implemented a new tailored calibration procedure for quantitative analysis of binary mixtures.

Main Results:

• Achieved significant signal enhancements using ODNP-enhanced NMR spectroscopy.
• Successfully quantified components in binary mixtures across a wide concentration range.
• Demonstrated the robustness of the new calibration procedure under challenging conditions.

Conclusions:

• ODNP-enhanced NMR spectroscopy, combined with a robust calibration, enables quantitative analysis of mixtures.
• This approach overcomes the sensitivity limitations of traditional NMR for diluted samples.
• The method is suitable for analyzing flowing samples in continuous-flow experiments.