Critical review and trends in forensic investigations of crossing ink lines

• Published in: TrAC, Trends in analytical chemistry (Regular ed.) Vol. 94; pp. 54 - 69
• Main Authors: e Brito, Lívia Rodrigues, Martins, Angêlica Rocha, Braz, André, Chaves, Amanda Belém, Braga, Jez Willian, Pimentel, Maria Fernanda
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2017
• Subjects: Crossing inks; Forensic chemistry; Ink analysis; Intersecting lines; Pen ink; Questioned documents; Intersecting lines; ATR-FTIR; Forensic chemistry; FDE; AFM; ALS; ESDA; LSCM; Pen ink; ANOVA; EDX; DCLS; SDI; MANOVA; FIB; Crossing inks; UV; VSC; IR; PLS-DA; Questioned documents; Ink analysis; PCA; ToF-SIMS; SERS; NIR; SEM; MCR
• ISSN: 0165-9936; 1879-3142
• DOI: 10.1016/j.trac.2017.07.005

This manuscript presents a critical discussion of the methods and techniques proposed for determining the sequence of crossing ink lines and their advantages, limitations and effectiveness are compared. Some trends are described, such as examination of physical features using optical and electron microscopy in the 60's and 70's, the use of the lifting technique in the 80's and the ESDA in the 90's. The year 2000 introduced chemical analysis with IR and Raman spectroscopy and also surface analysis with 3D laser Profilometry, for more objective examinations. The last decade has seen the application of the VSC and hyperspectral imaging, combined with chemometrics for automated, more informative and representative examinations. Nevertheless, interpretations remain visual and blind testing can be used for method validation. Some studies addressed some of the factors affecting the crossing of two ink lines but much of the physicochemical aspects remain uncomprehended and understudied. •Critical review of methods and techniques for determining the sequence of crossing lines.•Advantages, limitations and effectiveness of methods and techniques are discussed.•Techniques evolved from physical towards sophisticated chemical analysis.•Methods became objective, automated, more informative and representative.•Physicochemical processes involved in crossing lines are complex and understudied.