Determining the Relative Age of Ballpoint Inks Using a Single-Solvent Extraction Technique

An ink dating method based on solvent analysis was recently developed using thermal desorption followed by gas chromatography/mass spectrometry (GC/MS) and is currently implemented in several forensic laboratories. The main aims of this work were to implement this method in a new laboratory to evaluate whether results were comparable at three levels: (i) validation criteria, (ii) aging curves, and (iii) results interpretation. While the results were indeed comparable in terms of validation, the method proved to be very sensitive to maintenances. Moreover, the aging curves were influenced by ink composition, as well as storage conditions (particularly when the samples were not stored in "normal" room conditions). Finally, as current interpretation models showed limitations, an alternative model based on slope calculation was proposed. However, in the future, a probabilistic approach may represent a better solution to deal with ink sample inhomogeneity.

mentioning

confidence: 99%

Ink Dating Using Thermal Desorption and Gas Chromatography/Mass Spectrometry: Comparison of Results Obtained in Two Laboratories

Koenig

Bügler²,

Kirsch

et al. 2014

“…A prerequisite for this method is that the ink must contain a sufficient content of chloride salts. The extractability of dyes from ballpoint inks on paper is another approach that has been used for ink dating (2,3). The method has been discussed in the literature, but there remains some controversy about the technique (4).…”

mentioning

confidence: 99%

Age Determination of Ballpoint Pen Ink by Thermal Desorption and Gas Chromatography–Mass Spectrometry*

Bügler¹,

Buchner²,

Dallmayer³

2008

Two main approaches can be used for determining the age of an ink: indirect dating and direct dating. Indirect dating is based on the chemical analysis of an ink followed by comparison with known samples in a reference collection. The collection should contain information about the inks including the market introduction dates. This approach may allow for an anachronism to be detected. The second concept is based on measuring ink components that change with age. The analysis of solvents in ballpoint inks may be a useful parameter for determining the age of ink on paper. In a previous study, the authors demonstrated that thermal desorption of ink directly from paper, followed by chemical analysis using gas chromatography-mass spectrometry (GC-MS), is a promising procedure for characterizing ink-binder resins and solvents. Preliminary tests showed that monitoring the evaporation of ink solvent from ink on paper is not a suitable method for ink dating. Thermal analysis of ink on paper in two steps revealed that fresh ink releases a relative amount of solvent at a certain low temperature in a defined period of time, which decreases as the ink ages. As a consequence, this relative amount of solvent released at a certain low temperature, and its decrease with time, can be used to estimate ink age. This age-dependent parameter was studied in 85 different inks ranging in age from 1 week to 1.5 years. It was found that some inks showed a significant decrease of this parameter up to an age of several months, and that the aging process can be monitored within this period. For other inks, however, the age-dependent parameter decreases relatively fast, e.g., within a few days, to a constant level, which can be too fast for casework. Based on these results, a general procedure for assessing the age of ballpoint pen inks on paper was developed.

“…4). In 1987, Brunelle, the author of the present paper, reported a single solvent extraction procedure to estimate the age of ballpoint inks [17]. This procedure involves the extraction of inks with weak solvents, spotting the extract onto a TLC plate, and measuring the amount of ink extracted densitometrically.…”

Section: C(w) + C(s)mentioning

confidence: 99%

Ink Dating—The State of the Art

Brunelle¹

1992

Self Cite

Over the past 20 years, no other field of forensic science has had greater impact on the detection of fraudulent documents than the scientific examination of writing inks. This paper traces the development of ink dating techniques from the 1930s to 1990. Techniques used during this period are described and, when possible, illustrated. The emphasis is on ink dating techniques used today, with discussion of the value and limitations of these procedures.