Ferric reducing antioxidant potential (FRAP) of antioxidants using reaction flow chromatography.

High performance liquid chromatography coupled with post column derivatisation (HPLC-PCD) may be used to profile the antioxidant content of a sample. There are, however, drawbacks in the use of HPLC-PCD setups; namely the high volume reaction coils that are typically used lowering the observed separation efficiency. Reaction flow chromatography has the ability to overcome these inefficiencies by using a more efficient mixing technique inside the outlet fitting itself, post column reaction loops can be removed with resulting improvement in signal to noise response, plus the separation efficiency is maintained. We assessed two methods of HPLC-PCD antioxidant analysis based on the ferric reducing antioxidant power (FRAP) assay in both conventional and reaction flow HPLC-PCD modes. It was found that the reaction flow technique demonstrated significant advantages over the conventional technique in terms of signal to noise, linear range, precision and observed separation efficiency.