Forensic multi-technique profiling of fountain pen inks on paper

Fountain pen inks are increasingly encountered in forensic document examination, yet they remain comparatively underexplored in ageing-focused studies. This research establishes baseline characterisation of three commercial fountain pen inks (Pilot, Pelikan and Lamy) deposited on Double A A4 paper and analysed at a single time point (fresh ink after 30 minutes drying at room temperature). A multi-technique analytical approach was applied, including Thin Layer Chromatography (TLC), Gas Chromatography-Mass Spectrometry (GC-MS), Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR), Ultraviolet-Visible Spectroscopy (UV-Vis), Polarised Optical Microscopy (POM), Field Emission Scanning Electron Microscopy with Energy-Dispersive X-ray analysis (FESEM-EDX) and cyclic voltammetry using Screen-Printed Carbon Electrodes (SPCE). TLC revealed that all inks contained multiple dye components, with distinct retention factor (Rf) patterns useful for discrimination. GC-MS identified formulation-related additives, including substituted phenolic antioxidants and siloxane-related compounds, supporting differences in stability-related composition between brands. ATR-FTIR and UV-Vis provided complementary functional group and chromophore information, while POM and FESEM-EDX highlighted differences in ink distribution and surface morphology on paper fibres. Cyclic voltammetry produced distinguishable redox profiles across the inks, demonstrating value as a rapid, low-volume complementary method for ink comparison. Overall, this work provides a baseline dataset for fountain pen ink discrimination and highlights chemical, optical, microscopic and electrochemical features that may be tracked in future controlled ageing studies. Long-term ageing trends were not measured in this thesis.