Ames Laboratory - USDOE and Institute for Physical Research and Technology, Iowa State University, 109 Spedding Hall, Ames, IA 50011-3020, USA.
Forensic Sci Int. 2013 Sep 10;231(1-3):73-81. doi: 10.1016/j.forsciint.2013.04.016. Epub 2013 May 16.
Ink analysis is central to questioned document examination. We applied direct analysis in real time mass spectrometry (DART MS) to ballpoint, gel, and fluid writing ink analysis. DART MS acquires the mass spectrum of an ink while it is still on a document without altering the appearance of the document. Spectra were acquired from ink on a variety of papers, and the spectrum of the blank paper could be subtracted out to produce a cleanly isolated ink spectrum in most cases. Only certain heavy or heavily processed papers interfered. The time since an ink is written on paper has a large effect on its spectrum. DART spectra change radically during the first few months after an ink is written as the more volatile components evaporate, but the spectra stabilize after that. A library-search study involving 166 well-aged inks assessed the ability to identify inks from their DART spectra. The aggregate success rate was 92%.
油墨分析是 questioned document examination 的核心。我们将实时直接分析质谱 (DART MS) 应用于圆珠笔、凝胶和液体书写油墨分析。DART MS 在不改变文件外观的情况下获取文件上油墨的质谱。从各种纸张上的油墨中获取光谱，在大多数情况下，可以减去空白纸张的光谱，以产生干净分离的油墨光谱。只有某些重质或经过大量处理的纸张会产生干扰。油墨在纸张上的时间对其光谱有很大影响。自油墨书写在纸张上以来，在最初的几个月内，其光谱会发生剧烈变化，因为更易挥发的成分会蒸发，但在此之后，光谱会稳定下来。一项涉及 166 种经过长时间老化的油墨的库检索研究评估了通过 DART 光谱识别油墨的能力。总体成功率为 92%。
