Differentiating Writing Inks Using Direct Analysis in Real Time Mass Spectrometry
Article first published online: 19 JUN 2006
Journal of Forensic Sciences
Volume 51, Issue 4, pages 915–918, July 2006
How to Cite
Jones, R. W., Cody, R. B. and McClelland, J. F. (2006), Differentiating Writing Inks Using Direct Analysis in Real Time Mass Spectrometry. Journal of Forensic Sciences, 51: 915–918. doi: 10.1111/j.1556-4029.2006.00162.x
- Issue published online: 19 JUN 2006
- Article first published online: 19 JUN 2006
- Received 1 Oct. 2005; and in revised form 21 Jan. 2006; accepted 21 Jan. 2006; published 14 June 2006.
- forensic science;
- questioned documents;
- mass spectrometry;
- ink library
ABSTRACT: Writing ink analysis is used in establishing document authenticity and the sources and relative ages of written entries. Most analytical methods require removing samples or visibly altering the document. Nondestructive, in situ analysis of writing inks on paper without visible alteration is possible using mass spectrometry with a new ion source called Direct Analysis in Real Time. Forty-three different black and blue ballpoint, black fluid, and black gel inks were examined. Both dyes and persistent but thermally labile components of the inks contribute to the mass spectra, principally as protonated molecules [M+H]+. Numerous ink components were identified from the spectra. The spectra were placed in a searchable library, which was then challenged with two spectra from each of the 43 inks. The best match for each of the challenge spectra was correct for all but one ink, which matched with a very similar ink by the same manufacturer.