I have conducted phytochemical screening followed by FTIR for an aqueous plant extract and I want to know how to interpret the FTIR results to determine which phytochemicals are present based on the functional groups that have been determined/predicted by FTIR. Is there any other way to interpret the results?
As you will be aware, plants are a very rich source of phytochemicals and this will be reflected in your aqueous extract. The IR spectra of your extract will be complex, containing the overlapping spectra of every compound. You will not be able to identify any individual compound with any degree of certainty.
If you want to identify the components of your extract then you need to resort to a Metabolomics type experiment. You need to add in several chromatographic steps and then resort to GC-MS (headspace for volatiles), after appropriate derivatisation, and to LC-MS. The spectra can be searched against various libraries. Even then you will be left with many unknowns.
There are lists of functional groups commonly found in different classes of phytochemicals. Here is a general overview:
This is a simplified overview, and the actual functional groups present in phytochemicals can vary widely depending on the specific compound.
Phytochemicals are highly complicated since there are many number of Compounds found in a single extract. It is through FTIR we can able to interpret the functional groups