Abstract: X-ray photoelectron spectroscopy (XPS) is a kind of analytical technique with high sensitivity and resolution power.The nature of interaction between the S atom in protein of photographic gelatin and Ag⁺ was studied by XPS.The results in present paper showed that both methionine and methionine sulfoxide residues could link Ag⁺ through their S atoms.The amount of methionine sulfoxide residue was much more than that of methionine residue in the gelatin studied in our experiment,which suggested that methionine sulfoxide residue played a more important role than methionine residue in binding Ag⁺ with their S atoms.Moreover,the related characters of gelatins from different materials were compared.

Key words: photographic gelatin, Ag⁺, X-ray photoelectron spectroscopy