• Attard-Montalto, Nicola
• Jones, Bj
• Puit, Marcel De
• Doodkorte, Lisette
• Bailey, Melanie
• Ismail, Mahado
• Ojeda, Jesús J.
• Reynolds, Alan

Abstract

<p>This study thoroughly explores the use of time-of-flight secondary ion mass spectrometry (ToF-SIMS) for determining the deposition sequence of fingermarks and ink on a porous paper surface. Our experimental work has demonstrated that mapping selected endogenous components present in natural fingermarks enables the observation of friction ridges on a laser-printed surface, only when a fingerprint is deposited over this layer of ink. Further investigations have shown limited success on ink-jet printing and ballpoint pen inks. 51 blind tests carried out on natural, latent fingermarks on laser-printed surfaces; up to 14^th depletion with samples aged for up to 421 days have resulted in a 100% success rate. Development with ninhydrin was found to affect the fingermark residue through mobilisation of ions, therefore sequencing determination was compromised; whilst iodine fuming and 1,2-indanedione developers did not. This implied that selected development methods affected success in fingermark-ink deposition order determination. These results were further corroborated through inter-laboratory validation studies. The adopted protocol and extensive series of tests have therefore demonstrated the effectiveness and limitations of ToF-SIMS in providing chronological sequencing information of fingermarks on questioned documents; successfully resolving this order of deposition query. This journal is</p>

Topics

• Deposition
• porous
• impedance spectroscopy
• surface
• spectrometry
• selective ion monitoring
• secondary ion mass spectrometry