- Instrument Diagram:
- Instrument:
The current of electrons through the magnet coils create a magnetic field. The liquid helium decreases the temperature to 4 K (-269 °C), to provide an environment, with no electrical resistance within the coils.
- Sample Preparation:
The sample is dissolved in excess NMR solvent. The solvent MUST be free of the nuclei which we are analysing, for example if we are running a 1H NMR, the solvent can not have a 1H nuclei.
If you remember from the theory lesson, the nuclei with an even atomic number will not produce a magnetic field, therefore we use fully "deuterated" solvents. Deuterium is simply a Hydrogen atom with an extra neutron [ 2H ]. As you can see now hydrogen has an even atomic number and will not be detected by the NMR instrument.
Common NMR solvents used are:
1) deutero-tri-chloromethane CDCl3.
2) dimethyl sulfoxide-d6 CD3SOCD3 [DMSO-d6].
- NMR Spectrum Production:
Strength of a magnet is really important for both signal-to-noise ratio and resolution of the spectrum. As discussed in the theory section, the more the strength of magnetic field, the better the resolution and also the noise to signal ratio.
