Imaging mass spectrometry of fingermarks on brass bullet casings using sample rotation

Abstract

A sample rotation stage and image stitching algorithm were developed to obtain ToF-SIMS images of the entire surface of a bullet casing. This enabled detection of fingermarks on casings that showed no evidence of marks using conventional techniques.

Interpol review of fingermarks and other body impressions (2019 – 2022)

“…Preliminary/Pilot studies – Airflow-assisted DESI-MSI to image sebum-rich and contaminated fingermarks on paper [ 197 ]; LADI-MSI to image sebum-rich or contaminated fingermarks [ 179 ]; MALDI-FT-ICR-MSI to image fingermarks previously covered with blood [ 215 ]; use of carbon-based black powder [ 195 ] or titanium dioxide-based white powder [ 196 ] as matrixes to image sebum-rich or contaminated fingermarks by HRMS-MALDI-MSI; combined use of DART-HRMS and MALDI-MSI to image contaminated fingermarks [ 182 ]; Raman imaging to visualize fingermarks detected by lysozyme-specific aptamer-coated gold nanoparticles [ 216 ]; Sagnac UV FT imaging spectroscopy to image fingermarks spiked with vitamins C and B6 [ 217 ]; use of a gold-coated nanostructured silicon substrate compatible with SALDI-MSI and SERS [ 180 , 181 ]; SECM imaging of fingermarks previously transferred to a nitrocellulose membrane [ 218 , 219 ]; SERS imaging of fingermarks previously detected by SMD II [ 220 ]; ToF-SIMS to flatten fingermarks left on cartridge cases [ 221 ]; ToF-SIMS combined with a neural network to separate overlapped fingermarks [ 222 ]; XPS to image the presence of lead, lead oxide, titanium dioxide, and caffeine in fingermarks [ 187 ].…”

“…Other electrodeposition processes were proposed: cobalt oxide films on stainless steel [ 415 ], copper on aluminium [ 416 ], nickel/phosphor composites on copper [ 417 ]. In a chemical imaging context, Lee et al presented a rotation device used in combination with ToF-SIMS to flatten the fingermarks left on cartridge cases [ 221 ]. Note: these preliminary/pilot studies relying on limited sample sets (e.g., one donor, few depositions, sebum-rich secretions, fresh fingermarks), an overestimation of the reported performances is expected.…”

Expanding the Efficacy of Fingermark Enhancement Using ToF-SIMS

“…The application of ToF-SIMS to fingermarks has been demonstrated previously by Szynkowska et al, Lee et al, and Bailey et al [13][14][15]. Whilst previous work has demonstrated the potential of ToF-SIMS to provide higher sensitivity compared to Category A processes [16,17], there is no data to show how generally applicable this improvement is.…”

TOF-SIMS study of latent fingerprints on challenging substrates with the aid of transfer films

“…In addressing this, certain researchers have proposed a rotating sample holder to maintain a consistently perpendicular sample detection surface relative to the analyzer. 25,26 However, this approach's applicability is limited by the surface curvature of the sample it can detect. Specically, it cannot accommodate signicant surface curvature and still presents constraints for larger-sized or irregularly curved samples.…”