Dear Rebecca,

you must have samples of very pure free fatty acids (e.g. free of conjugated impurities / ) for forensic work in order to compare with old and new publications.

Have you NIR and NMR and UV-Vis pictures (as jpg or pdf)?. Can you send them via Message ( Message is confidential)?

If you give :

What is a reliable source for absorption spectra of free fatty acids?

in Google Scholar, you 'll earn a lot of references about your question.

Good luck for your research.

J.R.G