Determination of deposition order of blue ballpoint pen lines by MeV Secondary Ion Mass Spectrometry

Abstract Secondary Ion Mass Spectrometry using MeV ion excitation was utilised for the analysis of optically indistinguishable intersecting ballpoint pen lines on paper. It was demonstrated that the technique was able to identify different colorants (dyes and synthetic organic pigments) with high efficiency and in a single measurement. The analysis of ink-ink intersections was performed using the Time-of-Flight mass spectrometer for MeV Secondary Ion Mass Spectrometry. This technique is attached to the heavy ion microprobe at the accelerator facility, and employs focused 8 MeV Si 4+ ions for the surface analysis. Molecular imaging allowed for successful identification of sequence deposition order of otherwise optically indistinguishable intersecting lines.