Breakdown of collagen in the aged leathers is supposed to be partly due to hydrolysis of peptide bonds. Hence alpha-amino groups are liberated and can be detected using the technique we chose: a modification of the PITC technique developed by Pehr Edman in the early fifties, which allows the extent and location of such hydrolytic breakdown to be followed. Liquid chromatography is a suitable technique for separation and identification of PTH aminoacids. Attempts were made on amino acids, two tripeptides, one polypeptide and collagen in order to set a reliable derivatization technique and to establish conditions for the best separation. The purpose of this paper is to show the first results obtained for historical leather and artifically aged leathers, although no quantitation was taken into consideration. This study is still in progress.