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Updated: Apr 4, 2026
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Dissolution Dynamic Nuclear Polarization Instrumentation for Real-time Enzymatic Reaction Rate Measurements by NMR
Published on: February 23, 2016
11.3K
Direct dynamic nuclear polarization targeting catalytically active (27)Al sites
Alicia Lund1, Ming-Feng Hsieh, Ting-Ann Siaw
1Department of Chemistry and Biochemistry University of California Santa Barbara, Santa Barbara, CA 93106-9510, USA. songi@chem.ucsb.edu.
Physical Chemistry Chemical Physics : PCCP
|September 15, 2015
Summary
Direct (27)Al Dynamic Nuclear Polarization (DNP) signal enhancement depends on radical probe adsorption. Using 4-amino TEMPO on Al-SBA-15 yielded a ~13x signal boost, significantly higher than other probes.
Area of Science:
- Solid-state Nuclear Magnetic Resonance (NMR) Spectroscopy
- Materials Science
- Physical Chemistry
Background:
- Dynamic Nuclear Polarization (DNP) enhances NMR signals.
- Al-SBA-15 is a mesoporous material with potential catalytic applications.
- Surface interactions influence DNP efficiency.
Purpose of the Study:
- To systematically investigate direct (27)Al DNP using various mono-radical probes.
- To correlate DNP enhancement with radical probe adsorption and local concentration on Al-SBA-15 surfaces.
- To understand the factors governing (27)Al DNP efficiency in mesoporous materials.
Main Methods:
- Dynamic Nuclear Polarization (DNP) experiments on (27)Al nuclei.
- Electron Spin Echo Envelope Modulation (ESEEM) for probe-surface interactions.
- Continuous Wave (cw) Electron Paramagnetic Resonance (EPR) for lineshape analysis.
- Utilizing different mono-radical probes (4-amino, 4-carboxy, 4-hydroxy TEMPO) with varying charge states.
Main Results:
- A (27)Al signal enhancement factor of ~13 was achieved using 4-amino TEMPO.
- Radical probes with stronger adsorption to negatively charged sites (Al-SBA-15) showed higher DNP enhancement (~13x vs. ~3-4x).
- Proximity and local concentration of spin probes to surface aluminum sites were identified as key factors for direct (27)Al DNP enhancement.
Conclusions:
- The adsorption affinity of radical probes significantly impacts direct (27)Al DNP efficiency on Al-SBA-15.
- Targeted probe selection based on surface interactions can optimize (27)Al NMR sensitivity.
- This study provides insights into enhancing NMR detection of aluminum in mesoporous materials.
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