Denman John A, Kempson Ivan M, Skinner William M, Kirkbride K Paul
Ian Wark Research Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia.
Forensic Sci Int. 2008 Mar 5;175(2-3):123-9. doi: 10.1016/j.forsciint.2007.05.017. Epub 2007 Jul 12.
The characterisation and comparison of pencil markings on paper is an area of questioned document analysis that has previously not received much attention. Despite this, there would be value in an examiner being able to analyse two pencil markings and coming to a conclusion about whether they were from a similar or different source. Previous studies have analysed raw materials and bulk pencil cores for purposes of characterisation and differentiation, but to date, no studies have successfully analysed pencil markings non-destructively off a paper substrate. In this work, pencils from a number of manufacturers were analysed by inductively coupled plasma mass spectrometry (ICP-MS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Analysis of data using multivariate techniques (principal component analysis), showed that ToF-SIMS can successfully be used to analyse such pencil markings to deduce whether two markings can be differentiated, in terms of inorganic elemental composition. It was possible to discriminate between pencil markings from different manufacturers, and it was also indicated that pencils from the same manufacturer, but discrete batches, can be significantly different.
纸张上铅笔痕迹的特征描述与比较是文件检验分析领域的一个方面，此前并未受到太多关注。尽管如此，对于检验人员而言，能够分析两条铅笔痕迹并得出它们是否来自相似或不同来源的结论是有价值的。以往的研究为了特征描述和区分目的，分析了原材料和铅笔芯，但迄今为止，尚无研究成功地对纸张基底上的铅笔痕迹进行无损分析。在这项工作中，采用电感耦合等离子体质谱法（ICP-MS）和飞行时间二次离子质谱法（ToF-SIMS）对多家制造商生产的铅笔进行了分析。使用多元技术（主成分分析）对数据进行分析表明，就无机元素组成而言，ToF-SIMS能够成功用于分析此类铅笔痕迹，以推断两条痕迹是否能够区分开来。能够区分不同制造商的铅笔痕迹，并且还表明来自同一制造商但不同批次的铅笔可能存在显著差异。
