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A 1H-NMR thermometer suitable for cryoprobes
M Findeisen1, T Brand, S Berger
1University of Leipzig, Institute of Analytical Chemistry, Linnéstr. 3, D-04103 Leipzig, Germany.
Magnetic Resonance in Chemistry : MRC
|December 13, 2006
Summary
Nuclear Magnetic Resonance (NMR) thermometry using perdeuterated methanol offers a solution for modern cryoprobes. This method establishes a reliable temperature-dependent chemical shift relationship, overcoming limitations of traditional NMR thermometers.
Area of Science:
- Nuclear Magnetic Resonance (NMR) Spectroscopy
- Materials Science
- Physical Chemistry
Background:
- Established Nuclear Magnetic Resonance (NMR) thermometers utilize temperature-dependent chemical shifts in neat or concentrated solutions like ethylene glycol or methanol.
- These traditional methods are incompatible with modern cryoprobes due to significant radiation damping caused by the probe's high quality (Q) factor.
Purpose of the Study:
- To develop a reliable NMR thermometry method suitable for modern cryoprobes.
- To establish and validate a temperature-dependent chemical shift relationship using a specific deuterated solvent.
Main Methods:
- Utilized perdeuterated methanol as the sample for NMR thermometry.
- Established a quantitative relationship between chemical shift difference and temperature.
- Verified the accuracy of the NMR thermometer by comparing measurements with a calibrated Platinum-100 (Pt-100) resistor.
Main Results:
- A precise relationship between the chemical shift difference and temperature was determined for perdeuterated methanol.
- This temperature-chemical shift relationship was accurately described by a quadratic equation.
- In-situ temperature measurements within the cryoprobe were confirmed using a Pt-100 resistor.
Conclusions:
- Perdeuterated methanol is a viable and effective sample for NMR thermometry in modern cryoprobes.
- The established quadratic relationship provides a robust method for accurate temperature determination.
- This approach overcomes the limitations of traditional NMR thermometry in high-Q probes.
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