| Available from UMI in association with The British Library.; Luminescence of fingerprint residue (FPR) has been investigated. FPR is found to absorb strongly at about 280 nm and fluoresces in the range 300 nm-400 nm. It has been shown, using a combination of fluorescence spectroscopy and High Performance Liquid chromatography, that the fluorescence is mainly due to two of the three aromatic amino acids; tyrosine and tryptophan.; An HPLC assay was developed using fluorescence spectrometric detection. For different donors' residues, tyrosine concentrations were between 19.7 and 103.3 ng per finger washing, and for tryptophan, between 9.8 and 35.2 ng per finger washing. FPR was shown to contain approximately 3:1 tyrosine:tryptophan. The contribution from phenyl alanine to the bulk fluorescence is negligible, since none was found above the limit of detection.; A comparison of the fluorescence emission spectra from 'synthetic' FPR (3:1 tyrosine:tryptophan in a 50:50 methanol:water mix) with real FPR shows that tyrosine and tryptophan in the 300 nm-400 nm region.; FPR was found to exhibit low temperature phosphorescence (LTP). At 77 K, the FPR from 9 different donors produced phosphorescence in the range 392 nm to 429 nm, with recorded, phosphorescence lifetimes of up to 5.0 s. This is in good agreement with the LTP of tyrosine and tryptophan. FPR did not exhibit enhanced room temperature (RTP) phosphorescence using filter paper, cyclodextrins and external heavy atoms effects. Attempts to enhance RTP with "super-glue" were unsuccessful.; Fluorescence lifetime measurements and time resolved emission spectroscopy (TRES) of FPR were measured using single photon counting apparatus. Results showed good agreement with those from tyrosine and tryptophan.; Contrary to reports from some forensic workers, riboflavin was not found in FPR. The fluorescence lifetimes of riboflavin and its two degradation products (lumichrome and lumiflavin) were measured and are presented. These show that riboflavin, lumichrome and lumiflavin can all be discriminated from each other spectrally (absorption and fluorescence), as well as by fluorescence lifetimes. |
