Development of fingermark on the surface of fired cartridge casing using amino acid sensitive reagents: Change of viewpoint

Four amino acid sensitive fingermark enhancement reagents (ninhydrin, 5-methylthioninhydrin (5-MTN), 1,8-diazafloren-9-one (DFO), 1,2-indandione (1,2-IND) were used for the development of fingermark on the surface of brass. The reagents were used for the detection of a trace amount of metallic ion on the surface of cartridge casings to develop latent fingermarks. Ninhydrin-l-alanine (NIN-ALA), 5-MTN-l-alanine (MTN-ALA), DFO-l-alanine (DFO-ALA), 1,2-IND-l-alanine (IND-ALA) complexes were prepared and applied to the fired cartridge casings, for the further enhancement of fingermarks developed by corrosion on the surface of brass. Of the four complexes, NIN-ALA and MTN-ALA complexes induced color changes to enhance fingermarks on fired cartridge casings, but photoluminescence was not observed. About 31% of cartridge casings treated with MTN-ALA showed enhanced fingermarks. DFO-ALA and IND-ALA did not show any enhancement of fingermarks.