Hello Amrita ,you know that you serum content of proteins (ppc) so you will follow the change in the stretching frequency of the (C=O)of the amide bond at 1650 _+ . you need to use AquaSpec cell which used only for this purpose .
this application is present in FT-IR from Bruker co. you can see this attached file CONFOCHECK: FT-IR System for Protein Analytics. I hope this will help.