Discrimination of Blue and Black Ballpoint Pen Inks for Forensic Investigations

Abstract

Background: Great attempts have been made to fight fraud and falsification of crucial documents such as travel documents. However, document fraud and falsification are still rampant. This study aimed to determine the profile of Kenya's blue and black ballpoint pens inks. A total of ten ballpoint pen inks were included in the study. Of this, six were blue ballpoint pen inks, and the remaining four were black from distinct manufacturers. Methods: The techniques used for pens ink analysis were thin-layer chromatography (TLC), Fourier transform infrared spectroscopy (FTIR), and ultraviolet-visible (UV-vis) spectroscopy. Results: TLC showed a variation in the number of pigments in pen inks with a discriminating power (DP) of 0.87 and 0.83 for blue and black ballpoint pens, respectively. UV-Vis spectroscopy had a DP of 0.93 for blue pen inks and 0.67 for black pen inks, whereas FTIR spectroscopy had a DP of 1.0 for both blue and black pen inks. Hydroxyl, carboxyl, amino, nitro, and ester/ether functional groups were detected in blue and black pen inks. Lastly, multivariate analysis revealed that absorption of the blue and black pen inks in either methanol or ethanol was not different (P> 0.05). Conclusion: Taken together, findings from this study demonstrate the qualitative characteristics and functional group profile of blue and black ballpoint pen inks. However, more studies are needed to establish a reference for pen ink analysis for forensic investigations in Africa and beyond.