title: Statistical discrimination of black gel pen inks analysed by laser desorption/ionization mass spectrometry.
abstract: Pearson correlation coefficients were applied for the objective comparison of 30 black gel pen inks analysed by laser desorption ionization mass spectrometry (LDI-MS). The mass spectra were obtained for ink lines directly on paper using positive and negative ion modes at several laser intensities. This methodology has the advantage of taking into account the reproducibility of the results as well as the variability between spectra of different pens. A differentiation threshold could thus be selected in order to avoid the risk of false differentiation. Combining results from positive and negative mode yielded a discriminating power up to 85%, which was better than the one obtained previously with other optical comparison methodologies. The technique also allowed discriminating between pens from the same brand.
authors: Institut de Police Scientifique, Faculty of Law and Criminal Sciences, University of Lausanne, Bâtiment Batochime, 1015 Lausanne, Dorigny, Switzerland. celine.weyermann@unil.ch
authors: Céline
authors: C
authors: Weyermann
authors: Lukas
authors: L
authors: Bucher
authors: Paul
authors: P
authors: Majcherczyk
authors: Williams
authors: W
authors: Mazzella
authors: Claude
authors: C
authors: Roux
authors: Pierre
authors: P
authors: Esseiva