posted by anon on .
What advantages does H NMR have over melting point in the determination of purity?
Depending on the materials involved
1. 1H nmr is far more sensitive than mpt when looking for an impurity. This is especially true if the impurity has a prominant peak (say CH3) in an area of the spectrum where the bulk material does not
2. It is often possible to identify an impurity from the nmr spectrum. Indeed some modern instruments will allow you to subtract one sprectum from another so that you can identify the impurity.
3. 1H nmr also allows you to check the purity of a novel compound when you don' know the mpt. of the pure material.
The downside of course is cost and availability. It is much quicker and cheaper to carry out a mpt determination.
thank you very much for the help.