title: Determination of the deposition order of overlapping latent fingerprints and inks using secondary ion mass spectrometry.
abstract: A new protocol using time-of-flight secondary ion mass spectrometry (ToF-SIMS) has been developed to identify the deposition order of a fingerprint overlapping an ink line on paper. By taking line scans of fragment ions characteristic of the ink molecules (m/z 358.2 and 372.2) where the fingerprint and ink overlap and by calculating the normalized standard deviation of the intensity variation across the line scan, it is possible to determine whether or not a fingerprint is above ink on a paper substrate. The protocol adopted works for a selection of fingerprints from four donors tested here and for a fingerprint that was aged for six months; for one donor, the very faint fingerprints could not be visualized using either standard procedures (ninhydrin development) or SIMS, and therefore the protocol correctly gives an inconclusive result.
authors.affiliation: Surrey Ion Beam Centre, Advanced Technology Institute, University of Surrey, Guildford, Surrey, GU2 7XH.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Bright
authors.forename: Roger P
authors.initials: RP
authors.lastname: Webb
authors.forename: Stephen
authors.initials: S
authors.lastname: Bleay
authors.forename: Steven
authors.initials: S
authors.lastname: Hinder
authors.forename: Neil I
authors.initials: NI
authors.lastname: Ward
authors.forename: John F
authors.initials: JF
authors.lastname: Watts
authors.forename: Karen J
authors.initials: KJ
authors.lastname: Kirkby
authors.forename: Melanie J
authors.initials: MJ
authors.lastname: Bailey
mesh_terms: D003878:Dermatoglyphics; D006801:Humans; D007281:Ink; D010209:Paper; D012680:Sensitivity and Specificity; D018629:Spectrometry, Mass, Secondary Ion / Q000379:methods*