Nuclear Magnetic Resonance (NMR) in liquids
Supervisor: Dr. Rustem Valiullin
This experiment imparts the basics of NMR external magnetic fields. The measurements are done on the commercialNMR-Analyser “minispec PC 20” with a resonance frequency of 20MHz made by the Bruker Analytik GmbH. The data analysis is done with a PC. One may use a software which was designed for field gradient pulse NMR spectroscopy or the program “WIN-NMR” developed by above company.
Theoretical basics:
- Equilibrium magnetisation in a static magnetic field
- Equation of motion of the magnetisation
- Influence of a high-frequency field, 90°- and 180° pulse
- Longitudinal and transversal relaxation
Construction of a NMR-pulse spectrometer:
- Production of high-frequency pulses with different phase
- Decoupling of a transmitter receiver
- Phase-sensitive rectifying, rectification with diodes
- Digitisation (Sampling-theorem), signal-noise ratio
Experimental tasks:
- Calibration of the 90°- and 180° pulses
- Determination of longitudinal relaxation time
- Registration of free induction, determination of the homogeneity of the magnetic field
- Hahn’s echo
- Carr-Purcell-, Carr-Purcell-Meiboom-Gill pulse sequence
- Determination of the coefficient of diffusion of a liquid in an inhomogeneous magnetic field
- Resolution of NMR-signals of a two component mixture (measurement of the chemical shift)
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