NCJ Number
225617
Journal
Journal of Forensic Sciences Volume: 53 Issue: 6 Dated: November 2008 Pages: 1468-1473
Date Published
November 2008
Length
6 pages
Annotation
This article reports on the methodology and results of using ultraviolet-visible (UV-VIS) spectrophotometry, thin layer chromatography (TLC), and diffuse reflectance Fourier transform infrared spectroscopy (FT-IR) in examining a population of 21 black and 12 blue ballpoint writing inks.
Abstract
Based on corroborative results of these methods, the discrimination power for UV-VIS, TLC, and FT-IR was 100 percent and 98 percent for the black and blue inks, respectively. The authors conclude that generally TLC and UV-VIS can be used to differentiate the colorant components (dyes and some pigments) found in inks. FT-IR can be used to identify some of the noncolorant components, so it is an excellent complementary technique that can be implemented into an analytical scheme for ink analysis. A total of 33 ballpoint pens (21 black and 12 blue) from different manufacturers and of different models were randomly acquired from several stationery shops in the Messina region of Italy. Lines were drawn with the pens on unlined sheets of the same batch of A4 white, 80 g/m2 office paper. Immediately after the deposition, the ink coming from lines approximately 1 cm long was extracted with 40 mL of absolute ethanol in a glass vial. In order to check the role of sampling on analytical results, another extraction with ethanol was performed directly from the pen ink reservoir. Blank paper was also treated with ethanol with the same procedure used for ink lines, in order to quantify the matrix effect. The procedures of UV-VIS, TLC, and FT-IR are described. 8 figures and 28 references