Amino acid profiling from fingerprints, a novel methodology using UPLC-MS

Abstract

Fingermark evidence is extensively used in criminal investigations. Hence, there have been many investigations into the chemical compounds present in fingerprint deposits. In this technical note we describe the analysis of non-derivatised amino acid profiles obtained from fingerprints. We used UPLC with an amide stationary phase and subsequent detection using a triple quadrupole MS/MS and TOF-MS detector. The linearity (R 2 ) was satisfactory for both MS detectors (>0.98 for all amino acids in the case of the triple quadrupole MS/MS and >0.96 in the case of the TOF-MS). Although the triple quadrupole had a higher sensitivity for most amino acids, both mass spectrometers were able to retrieve the amino acid profiles of fingerprints from 19 donors. Between these profiles, only minor differences were observed between the separate analyses on the different mass analyzers, mainly in L-proline, L-lysine and L-phenylalanine abundances. Surprisingly, the mean RSD in amino acid profiles from duplicate fingerprints turned out to be lower for the TOF-MS (18.6% AE 6.6% vs. 13.2% AE 3.8%), as did the mean RSD of the intraday reproducibility (8.22% AE 1.94% vs. 9.54% AE 3.07%).

The forensic exploitation of fingermark chemistry: A review

“…Androgenic steroids; carbohydrates for example, glycogen; carboxylic acids; proteins; sterols for example, cholesterol Ammonia; iron; water eccrine sweat (Atherton et al, 2012;Croxton, Baron, Butler, Kent, & Sears, 2010;de Puit, Ismail, & Xu, 2014;van Helmond et al, 2017).…”

Interpol review of fingermarks and other body impressions 2016–2019

“…It should be noted that these two studies require the identification of lifestyle markers (e.g., active molecules) and the creation of an exogenous compound database generated from an exhaustive range of products before being considered for casework. Amino acid profiling of 19 donors (fingermarks left on aluminium) was proposed using UPLC-ToF MS and UPLC-QqQ MS/MS [ 218 ]. From an analytical point of view, the authors determined the LOD and LOQ for all amino acids and emphasized the advantage of using an amide stationary phase to avoid a derivatization step.…”

Proteomics as a new tool to study fingermark ageing in forensics

“…Although fingermark residue is recognized as an important source of tell-tale (bio)molecules, it is not yet routinely used for forensic profiling in casework or in court. Nonetheless, recent research efforts have now placed illicit substances (and their metabolites), lipids, amino acids, DNA, RNA and proteins high on the forensic research agenda 6 – 13 . Fingermarks likely contain low amounts of endogenous proteins, compared to abundantly present lipids, salts and free amino acids 3 , and have only attracted limited attention from a proteomics point of view.…”