The strength of the magnetic field is a determining factor for the range of NMR spectrometer. that must be used for
temperature
frequencies
tesla
spin states
none of these
The Correct Answer and Explanation is :
The correct answer is frequencies.
Explanation:
Nuclear Magnetic Resonance (NMR) spectroscopy is a powerful analytical technique used to study molecular structures based on the interactions of atomic nuclei with an external magnetic field. The key factor that determines the range of an NMR spectrometer is the strength of the magnetic field, which directly affects the resonance frequency of the nuclei being studied.
1. Relationship Between Magnetic Field and Frequency
The resonance frequency ((\nu)) of a nucleus in an NMR spectrometer is governed by the Larmor equation:
[
\nu = \frac{\gamma B}{2\pi}
]
where:
- (\nu) = Resonance frequency of the nucleus (in MHz),
- (\gamma) = Gyromagnetic ratio (a constant specific to each type of nucleus),
- (B) = Magnetic field strength (in Tesla).
From this equation, we can see that frequency is directly proportional to the strength of the magnetic field. As the field strength ((B)) increases, so does the resonance frequency of the nuclei.
2. Impact on NMR Spectrometers
- NMR spectrometers are classified based on their operating frequency, which depends on the applied magnetic field.
- For example, a 1H NMR spectrometer operating at 300 MHz requires a magnetic field of approximately 7.05 Tesla, while a 600 MHz spectrometer requires around 14.1 Tesla.
- The choice of spectrometer frequency affects the resolution and sensitivity of the NMR experiment. Higher field strengths provide better resolution and sensitivity, allowing for more detailed molecular analysis.
3. Why Other Options Are Incorrect
- Tesla: While the magnetic field is measured in Tesla, the question asks about the determining factor for the spectrometer’s range, which is better described by frequency.
- Spin States: The number of spin states of a nucleus is intrinsic to the nucleus itself (e.g., protons have two spin states, +1/2 and -1/2) and does not determine the spectrometer’s range.
- Temperature: Temperature affects relaxation times and spectral broadening but does not define the spectrometer’s operational range.
Conclusion
Since the operating range of an NMR spectrometer is primarily defined by its resonance frequency, which depends on the applied magnetic field, the correct answer is frequencies.