The interaction between riboflavin and silver colloidal particles was studied with absorption and surface enhanced resonant Raman spectroscopy (SERRS).

FT-Raman and surface enhanced Raman spectra (SERS) of leucine and isoleucine, the only iso - mer in proteinic amino acids, on the silver colloidal substrate are recorded.

The United States Food and Drug Administrtion does not allow colloidal silver to be sold for this purpose.