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Supercritical Fluid Extraction and Chromatographic Analysis for the Dating of Inks, Final Report

NCJ Number
Date Published
January 1997
31 pages
This study used high-performance liquid chromatography (HPLC) to date inks from a collection of inks of known ages maintained by the Internal Revenue Service.
Ink was extracted from paper (19 dates and 3 pen types) at three different pressures using a supercritical fluid extraction unit and stored before HPLC analysis. Concentration changes of various ink components with respect to time were determined by comparing peak ratios. Representative chromatograms and ultraviolet spectra of eluting peaks from inks of different ages were developed. Aging curves were constructed to determine ink age by comparing changes in ink components as evidenced by HPLC analysis. Additional research is being conducted to assess the validity of the technique for determining the age of a document, using ink samples to which the analyst is blind. Tables and figures

Date Published: January 1, 1997