DATINK pilot study: an effective methodology for ballpoint pen ink dating in questioned documents

Area of Science:

• Forensic Science
• Analytical Chemistry

Background:

• Dating ink entries in questioned documents is a complex forensic challenge.
• Analyzing ink solvents is a potential method for determining ink age.
• Existing gas chromatography/mass spectrometry (GC/MS) methods for ink dating have limitations.

Purpose of the Study:

• To develop a novel ink dating methodology (DATINK) for ballpoint pen inks.
• To utilize the disappearance rate of volatile solvents for age estimation.
• To establish a mathematical model for ink age determination.

Main Methods:

• Utilized multiple headspace solid-phase microextraction (MHS-SPME) coupled with GC/MS.
• Analyzed solvent content in ink entries from BIC® ballpoint pens.
• Modeled ink age using the β parameter, representing the remaining analyte fraction after successive extractions.

Main Results:

• The DATINK method successfully detected ink solvents up to five years old.
• Analysis of real-world samples showed a mean relative error of 21% in age estimation.
• The β parameter demonstrated a low standard deviation (0.002–0.004), indicating reliable modeling.

Conclusions:

• The DATINK methodology offers a promising approach for estimating the absolute age of ballpoint ink entries.
• Solvent disappearance, quantified by the β parameter, is a viable indicator for ink dating.
• Further validation could enhance its application in forensic document examination.