The interaction of L-tryptophan (Trp) with silver colloids was investigated at between pH values of 6.11 and 10.6 of the sol. The
measurements of surface-enhanced Raman bands of Trp in the colloidal solution indicate the evolution of interaction between
the metal particles and the molecules with increasing pH values for the sol. The experimental observations were explained
using the estimated atomic charge distribution in the zwitterionic and anionic forms of the residue, obtained by density
functional theory calculations. The variation in the ratio of the spectral intensities of the Fermi resonance bands with the
pH reflects the effect of the colloidal environment on Trp. The results obtained can be used as a marker for describing the
nature of the interaction of silver colloids with the specific terminus of the residue, at varying pH environments.
Department of Physics, Indian Institute of Technology Kharagpur
Motilal Nehru National Institute of Technology, Allahabad,
Copyright:DOI 10.1002/jrs.3083 © 2012 John Wiley & Sons, Ltd.