Pararosaniline and crystal violet tagged montmorillonite for latent fingerprint investigation

• Published in: Applied clay science Vol. 87; pp. 235 - 244
• Main Authors: Sarıoğlan, Şerife, Gürbüz, Serkan, İpeksaç, Tuğba, Gürtekin Seden, Merve, Erol, Melek
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 01.01.2014; Elsevier
• Subjects: Bentonite; Crystal violet; Crystals; Earth sciences; Earth, ocean, space; Exact sciences and technology; Fingerprint powder; Fingerprints; Fluorescent fingerprint powder; Fourier transforms; Glass; Infrared spectroscopy; Mineralogy; Montmorillonite; Pararosaniline; Prints; Silicates; Bentonite; Pararosaniline; Crystal violet; Fingerprint powder; Montmorillonite; Fluorescent fingerprint powder; scanning electron microscopy; crystals; Fourier transformation; pigments; sodium ion; ion exchange; X-ray diffraction; metals; exhibits; smectite; montmorillonite; fluorescence; clay minerals; sheet silicates; silicates; infrared spectroscopy
• ISSN: 0169-1317; 1872-9053
• DOI: 10.1016/j.clay.2013.11.012

Use of cationic pigment-intercalated bentonite (montmorillonite, Mt) as the latent print development powder was investigated. The cationic dyes, crystal violet (CV) and pararosaniline (PS), were substituted with sodium ions present in the interlayers of Mt by ion exchange mechanism. Organophilic montmorillonites (OMts) were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), elemental analysis and Fourier transform infrared spectroscopy (FTIR). TGA results determined the average amount of dye molecules in OMts as 52mmol/100g for both PS and CV. Modified bentonite powders were applied to develop fresh and aged (1, 7 and 15days) fingermarks deposited on non-porous surfaces such as glass, metal and porcelain using a fiberglass brush. Sharp and clear prints with complete ridge details were developed on glass and metal surfaces even for the 15-day-old fingermarks. Surprisingly, CV- and PS-intercalated fingerprint powders successfully worked for the development of the seven-month-old fingerprints on the glass surface. In contrast, physically mixed bentonite and dye mixtures were not very successful in the development of even fresh fingerprints on the glass surface. CV-tagged bentonite also exhibited strong fluorescence at around 500nm when excited at 450nm. [Display omitted] •Cationic pigment intercalated bentonite was prepared as fingerprint powder.•Colored powder was used to develop fresh or aged fingermarks on different surfaces.•Successful results were obtained even with 7-month-old fingerprints on glass.•CV-tagged bentonite showed strong fluorescence.•Intercalated powders gave superior results than physically mixed dye and bentonite.