A method based on profiling of dye components by electrospray ionization mass spectrometry (ESI/MS) is described for the characterization of ballpoint pen inks. The method involves benzyl alcohol (30 _L) extraction of ink from paper. The extracts of ink lines 1 and 5 mm in length are used for direct ESI/MS analysis in positive and negative modes, respectively. The instrumental analysis takes 3 min. Basic and acid dyes in the inks are detected in the positive and negative modes, respectively, with each dye yielding one or two characteristic ion peaks. The mass spectrum, which is mainly a compositional signature of the dyes in the ink, was not affected by the type of paper from which the ink was extracted, or by natural ageing of the ink on document in the absence of light. However, exposure to fluorescent illumination caused dealkylation of polyalkylated basic dyes and resulted in changes in the homologous distribution of the dyes. In this study, a total of 44 blue inks, 23 black inks, and 10 red inks have been analyzed, and the mass spectra were used to establish a searchable library. ESI/MS analysis provides a simple and fast way to compare ink specimens and in combination with on-line library search permits rapid screening of inks for forensic document investigations.

We wish to describe further developments to a method previously reported on the detection of 2-phenoxyethanol in ink. The solid-phase microextraction (SPME) sampling technique, together with gas chromatography-mass spectrometry (GC-MS), has been used to quantify solvents in writing ink. In conventional approaches, the analysis of ink on documents requires some degree of destructive sampling. The methods commonly used remove ink samples from paper using a scalpel or a paper punch. To avoid document destruction, a sampling cell was constructed that allows solvents to be adsorbed directly onto the SPME fiber from the headspace above the document surface. Analytes (ink volatiles) are then desorbed from the SPME fiber on a gas chromatograph equipped with a mass selective detector (GC-MSD). With this method, it was possible to detect the presence of ink solvents on documents for a period lasting up to c. 2 years.