Monitoring ink degradation for forensic investigations by HPLC

CHED 241

Jamie L. Hornock, hornockj@etown.edu and Kristi A. Kneas, kneask@etown.edu. Department of Chemistry and Biochemistry, Elizabethtown College, One Alpha Drive, Elizabethtown, PA 17022
In forensic investigations, the validity of questioned documents is becoming increasingly important. One approach that can be useful in dating the writing on a questioned document is to monitor the compositional changes of the ink with time. Based on differences in degradation products of the ink, it is possible to discern between writing that is original to the document and writing that has been added at a later time. Extraction methods and HPLC measurements for inks of different colors and brands are described, as are studies to determine the time range over which measurable changes in ink degradation products are observed. The feasibility of this approach for use in both the crime laboratory and the teaching laboratory is discussed.