Andrasko Jan
SKL, National Laboratory of Forensic Science, Linköping, Sweden.
J Forensic Sci. 2002 Mar;47(2):324-7.
A method for comparison of the relative age of ink entries written by the same ballpoint pen on documents stored in darkness is presented. Inks were extracted from the document and analyzed by HPLC (high performance liquid chromatography). On aging, changes in the chemical composition of the inks were noted. These changes were similar to those observed when inks were exposed to light or heat. The aging was followed by using ternary diagrams constructed for dyes generally present in blue-colored inks--Crystal Violet, Methyl Violet, and Tetramethyl Para Rosaniline. The procedure is applicable for relative dating of ink entries in diaries, notebooks, etc., where often several ink entries are written by the same ink. However, a prolonged exposure of the document to daylight and/or artificial light (light from fluorescent tubes) as well as to extensive heat will render the whole procedure inapplicable. An example of the use of the proposed method in casework is given.
本文介绍了一种用于比较在黑暗中保存的文件上由同一支圆珠笔书写的墨水痕迹相对书写时间的方法。从文件中提取墨水并通过高效液相色谱法（HPLC）进行分析。随着时间推移，会注意到墨水化学成分的变化。这些变化与墨水暴露于光或热时观察到的变化相似。通过使用为通常存在于蓝色墨水中的染料（结晶紫、甲基紫和四甲基对玫瑰苯胺）构建的三元图来跟踪老化过程。该程序适用于日记、笔记本等中墨水痕迹的相对年代测定，其中通常有多个墨水痕迹是用同一墨水书写的。然而，文件长时间暴露在日光和/或人造光（荧光灯管发出的光）以及高温下会使整个程序无法适用。文中给出了该方法在实际案件工作中的应用示例。
