1
Q
What is TMS
A
This is an internal standard for both carbon and proton NMR
2
Q
What is chemical shift
A
This is the scale that compares the frequency of NMr absorption with the frequency of the refernce peak TMS
3
Q
What is deuterium
A
This is an isotope of hydrogen and does not produce a signal in the proton NMR spectrum
4
Q
NMR is a ..
A
Non destructive analytical technique
5
Q
Describe how nuclear magnetic resonance work
A
- some isotopes such as H1 and C13 have a property known as spin
- organic compounds put in a large magnetic field, the direction or these nucleons align with the direction of the magnetic field
- energy required to change alignment depends on the environment that the atom is in and can be compared to a standard
6
Q
What is the tms peak
A
0ppm
7
Q
What is a tms used for
A
Used to compare the values in the sample
8
Q
Why is tms a good internal standard
A
- contains both carbon and hydrogen so can be used for carbon and proton NMR
- produces one sharp signal as hydrogen atoms are in a single environment, as there is only one carbon atom this will also produce one signal in carbon-13 NMR
- it is non toxic
- low boiling point and volatile so it can easily be removed from the sample
- it is inert so is unlikely to react with chemical that is being investigated
