This study identified compounds of amino acids in fingerprint residue exposed to high temperatures, which decomposes latent fingerprints, with a view toward providing data needed to identify reagents suitable for developing such decomposed fingerprints.
The findings identified compounds in decomposed amino acids in fingerprints exposed to extreme heat that are viable candidates for a reagent that will develop fingerprints exposed to high temperatures. After exposing the amino acids of fingerprints to extreme heat, the following three characteristic compounds were found in two of the amino acids (alanine and aspartic acid): dimethlypiperazine-2,5-dione, maleimide, and 2,5-furandione. Despite the fatty appearance and texture of the decomposed fingerprint residue, it did not yield any previously reported animal or human tissue combustion products. The chromatographic presence of organics such as isopropyl palmitate, however, suggests that environmental factors may combine with the decomposed amino acid markers in fingerprint residue; however, there is no evidence that indicates these organics interfere with the markers or will impede a reaction between the markers and a target-specific reagent. The scope of this study was limited to the analysis of amino acid components of fingerprint residue that are likely to be present at analytically suitable concentrations and are known substrates for fingerprint-developing reagents such as ninhydrin and diazafluoren-9-one. The most prevalent amino acids in fingerprint residue were analyzed: serine, glycine, ornithine, lysine, alanine, and aspartic acid. The collection of fingerprint residue for analysis was done by the extraction of cotton gloves in a Soxhlet extractor. The final phase of the study involved pyrolyzing (decomposing under extreme heat) the amino acids and the extracted fingerprint residue, followed by an analysis of the products with gas chromatography and mass spectrometry. 3 tables, 4 figures, and 8 references