Analysis of Ballpoint Pen Inks by Diffuse Reflectance Infrared Spectrometry

Abstract

Abstract The primary method for the analysis of inks is thin-layer chromatography (TLC), which only permits comparison of dye components. Studies have been done on the usefulness of diffuse reflectance (DR) with Fourier transform infrared (FT-IR) spectrometry, using a direct deposit sampling technique for the analysis of ballpoint pen inks. This technique allows screening of a composite ink as a whole, including its dye components, resins, and other additives. A total of 184 ink samples were analyzed by FT-IR, and searchable spectral libraries were created of both whole and extracted inks. The results indicate that the additional information provided by the DR analysis, combined with the complementary information from the TLC analysis, provides enhanced value to the forensic examination of inks.