Chromatography Forum

Greetings.

I was asked this question: what do you do to pin down or indentify the compound if you were given an unknown compound?

If one needs to work on ID impurities for API or intermediate, does he/she have to have STRONG background in organic chemistry?

Any imput would be appreciated
thanks a lot!

Depends what you mean by STRONG. You don't need to know how to do a 20 step synthesis with palladium catalysts, but you need a general understanding of how compounds can degrade.

what do you do to pin down or indentify the compound if you were given an unknown compound?

I start with FTIR, solubility, UV scan, GCMS.

I have also noticed that people with good background in organic chemistry/synthesis can make pretty educated interpretations on mass spectra fragmentation and they are pretty good with NMR spectra interpretation. Propably you will need both if you want to identify a somewhat complicated unknown compound.

There is a difference between really unkown compounds and impurities from known compounds

There are books on orgaic chemical identification/classification as well as spectral identification (IR, UV, NMR, MS) with examples for practicing. Recalling some tricks from elemental ion analysis doesn´t harm either. My books are some 40 years old, so I don´t think it will help to cite them. Anyway, if you have no idea what your substance is you need to understand how to use these books. For instance, for MS it is not only important to know something about typical fragmentation patterns, but also the nitrogen rule, mass - atomic composition relationship, and, and . . .

Thanks for everyone's reply.

Can anyone suggest any books for me? I am working more on finished products using HPLC and currently very interested in learning more and more about how to identify unknowns in API and intermediates with various analytical techniques, say IR, NMR, UV and LC/MS.

best