Chemical Shift Flashcards
1
Q
Deuterated solvents
A
Deuterium is isotope of hydrogen with one proton and one neutron. It has an even number of nucleons so produces no NMR spectrum. CDCl3 is a solvent so NMR can be carried out in solution. Carbon peak removed from spectrum, sample can be recovered by evaporating it off.
2
Q
D2O
A
Used to filter out absorptions due to -OH and -NH protons. It undergoes proton exchange with the protons on those groups. It doesn’t produce a signal which makes it easier to distinguish other absorption peaks.
3
Q
TMS
A
TMS is the standard for chemical shift measurements. It has 12 equivalent protons which gives rise to single sharp NMR signal. It’s unreactive and volatile so can be removed from sample easily.
