Analysis of ballpoint pen inks by field desorption mass spectrometry

Destructive identification of ballpoint pen ink was performed using field desorption mass spectrometry (FDMS) to determine the basic dyes in ballpoint pen ink. Seven different brands of black, blue, and red ballpoint pen inks (total: 21 samples) were examined in this study. A 1-mm section was cut from an ink Line drawn on paper and used as the sample. Extraction was performed with methanol. Analysis of each extract by FDMS showed the molecular ion peak of each dye and the black, blue, and red inks were then classified into 6, 6, and 6 types, respectively, based on the ions detected. The results indicated that it was possible to distinguish between manufacturers of ballpoint pens. This analysis of ballpoint pen inks was found to be effective and the method was applied to the analysis of an actual forensic sample.