PubMed · 17076006
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Lisa Stiles. 2006. Medscape.. https://pubmed.ncbi.nlm.nih.gov/17076006/
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The determination of the age of an ink entry from a questioned document is often an essential problem and a controversial issue in forensic sciences. Therefore, it is important to understand the aging process of the different components found in ink. The aim of this work was to study the drying process of ballpoint ink, characterised by the disappearance of volatile solvents from the ink entry. Phenoxyethanol is of particularly high interest as it is found in more than 80% of the blue ballpoint pens at different concentrations. Liquid extraction followed by splitless gas chromatography/mass spectrometry in the selected ion mode was used to measure the quantitative decrease of solvents from ink entries made with a blue Parker ballpoint pen. Quantities of ethoxyethoxyethanol, dipropylene glycol, phenoxyethanol and phenoxyethoxyethanol were studied in ink entries up to 1.5 years old, thus allowing to calculate aging curves for this particular pen. The low quantities of solvents (in the microgram range for a 1 cm ballpoint entry) were found to decrease quickly after deposition of the ink on paper through the competitive processes of evaporation and diffusion. Losses of up to 75% of solvents were observed after a few seconds. The amount of ethoxyethanol stopped decreasing after about 10 days (quantities reached the nanogram range for a 1 cm ballpoint entry), while the aging curves of dipropylene glycol, phenoxyethanol and phenoxyethoxyethanol level off considerably after 2 weeks. It was observed that ethoxyethanol, dipropylene glycol and phenoxyethanol can also migrate from one sheet of paper to another if placed close enough (e.g. in a book or a stack of papers), therefore contamination from fresh ink strokes from other paper sheets has to be taken into account for those solvents. In this paper we demonstrate that differentiation between fresh ink (<2 weeks) and older inks is possible under laboratory storage conditions. For real cases samples, more parameters have to be studied and other possible pathways have to be considered.
In their day-to-day work, carrying out complex tasks, forensic scientists use a combination of explicit, codified standard operating procedures and tacit knowledge developed through their ongoing practice. We show that tacit knowledge is an integral part of the activities of expert forensic science practitioners who continually add to their knowledge repertoire by engaging other scientists through communities of practice. We wish to shed fresh light on the gaining of tacit knowledge by forensic scientists during their apprentice formative years, termed as legitimate peripheral participation. In quantifying tacit knowledge exchanges, we use social network analysis, a methodology for the analysis of social structures, to map relational knowledge flows between forensic scientists within communities of practice at the Forensic Science Laboratory, Ireland. This paper sheds light on the importance of tacit knowledge within the training regime of forensic scientists and its recognition as equal to the part played by explicit knowledge.
Based on a short description of the areas of operation and competence of forensic medicine, current problems, structural deficits of the speciality and possible solutions are discussed. To give future to legal medicine as an academic discipline, research must be given priority over routine casework.