Variation in amino acid and lipid composition of latent fingerprints

Abstract

The enhancement of latent fingerprints, both at the crime scene and in the laboratory using an array of chemical, physical and optical techniques, permits their use for identification. Despite the plethora of techniques available, there are occasions when latent fingerprints are not successfully enhanced. An understanding of latent fingerprint chemistry and behaviour will aid the improvement of current techniques and the development of novel ones. In this study the amino acid and fatty acid content of 'real' latent fingerprints collected on a non-porous surface was analysed by gas chromatography-mass spectrometry.Squalene was also quantified in addition. Hexadecanoic acid, octadecanoic acid and cis-9-octadecenoic acid were the most abundant fatty acids in all samples. There was, however, wide variation in the relative amounts of each fatty acid in each sample. It was clearly demonstrated that touching sebum-rich areas of the face immediately prior to fingerprint deposition resulted in a significant increase in the amount of fatty acids and squalene deposited in the resulting 'groomed' fingerprints. Serine was the most abundant amino acid identified followed by glycine, alanine and aspartic acid. The significant quantitative differences between the 'natural' and 'groomed' fingerprint samples seen for fatty acids were not observed in the case of the amino acids. This study demonstrates the variation in latent fingerprint composition between individuals and the impact of the sampling protocol on the quantitative analysis of fingerprints.

Determination of the Deposition Order of Overlapping Latent Fingerprints and Inks Using Secondary Ion Mass Spectrometry

“…However, locating a fingerprint above text carries substantially greater evidential value (showing the suspect touched a document after it was written) than below. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 14 There are many variables which are known to affect the chemistry of a latent fingerprint including the donor, the age of the fingerprint and the environment to which the fingerprint has been exposed since deposition 2,23,24 . This, and the uncontrolled nature of fi...…”

Fatty Acid Structure and Degradation Analysis in Fingerprint Residues

“…GC-MS was used in 1999 to identify components of fingerprint residues, including free fatty acids, triglycerides, wax ester, amino acids, glycerol, cholesterol, and squalene [17], followed by several studies combining chromatography, mass spectrometry, and spectroscopic techniques [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35]. Gender determination [21], donor classification [21][22][23][24][25], and aging studies [26][27][28][29][30][31][32] were among the major targets of fingerprint research recently.…”

Development of Laser Desorption Imaging Mass Spectrometry Methods to Investigate the Molecular Composition of Latent Fingermarks

“…Much of the prior research for the detection and identification of endogenous substances in fingermarks has been carried out using gas chromatography-mass spectrometry (GC-MS). Despite the fact that this technique is destructive and limited to a small class of compounds (<500 Da), it allows the detection of endogenous substances, such as amino acids, fatty acids, wax esters, squalene, and cholesterol, as well as the detection of some exogenous substances coming from hair product, parfum residue, cosmetics, and skin lotion [11][12][13][14][15][16]. Many nondestructive MS techniques have been developped for the detection of endogenous and exogenous substances from fingermarks.…”