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NIR spectra of amine compound and its salts

jcg2000's picture

Dear All:
Can we use NIR to differentiate different salts of an amine compound, say, amphetamine sulphate, amphetamine hydrochloride, and amphetamine phosphate? Has anyone collected NIR spectra of these salts and made a comparision? It seems to me NIR should not tell the difference between the different types of salt of the same amine compound. But I do notice that these salts show different FTIR spectra. Please refer to for infrared spectra of the amphetamine salts. Is NIR also sensitive to the anionic part of an amine salt?
Thanks in advance!
Jerry Jin

Sheelagh Halsey's picture

I have looked at various salts, but not the particular ones you mention. One that comes to mind was a compound as a free base, hydrochloride and a tartrate, these all had significantly different spectra.