Examination of Gel Pen Inks Using Physical and Thin Layer Chromatographic Examination

The use of thin layer chromatography (TLC) in the examination of writing materials is well documented and a proven technique. As technology continues to develop new and better methods of manufacture, those methods will permeate society and give rise to different products. This has occurred within the field of writing materials, as both instruments and inks have changed over time from nib pens to ball pens and from natural inks of iron to inks of pigment suspensions in water-based polymer gels. This most recent development, gel pens, combines ball pens with pigmented polymer gel ink. The gel pen presents a challenge to the forensic examiner, which is addressed initially with this study, including both traditional physical examinations, chemical spot tests, and TLC. A total of 98 different samples of gel pens were examined and yielded examination results that provided for discrete discrimination of over 35% of the gel pens.