The Use of 1,8-Diazafluoren-9-one (DFO) for the Fluorescent Detection of Latent Fingerprints on Paper. A Preliminary Evaluation

Abstract The use of a new amino acid reagent 1,8-diazafluoren-9-one (DFO), which produces a highly fluorescent species with latent fingerprints on paper, is described. Spectral characteristics of the fluorescent fingerprint show excitation (λex approximately 470 nm) and emission (λex approximately 570 nm) maxima in the visible part of the spectrum. Some printing inks fluoresce under these conditions and would therefore hinder fingerprint detection, but optical brighteners present in paper do not interfere. Fluorescent fingerprints visualized by DFO revealed more fingerprint detail than ninhydrin, the standard method for such surfaces.