DFO (1,8-Diazafluoren-9-one) is a fluorescent dye forming highly fluorescent derivatives with amino acids (excitation ~470 nm; emission ~570 nm). Used for the detection of latent fingerprints on paper with high sensitivity. 1,8-diazafluoren-9-one (DFO) is used in the forensic field to enhance latent fingerprints deposited on porous surfaces due to the formation of fluorescent products by reacting with the amino acids present in the papillary exudate. DFO has been the most used because of its excellent enhancing properties, even if it is more expensive and relatively toxic than the 1,2-IND. It reacts with the amino acids contained in the natural secretions, giving a pale red/magenta product, which also has also has a strong luminescence at room temperature without the need for further treatment (such as adding metal salts).
