Verma Neha, Kumar Raj, Sharma Vishal
Institute of Forensic Science and Criminology, Panjab University, Chandigarh 160014, India; DFSS Fellow, Central Forensic Science Laboratory (Document Division), Chandigarh 160036, India.
Institute of Forensic Science and Criminology, Panjab University, Chandigarh 160014, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2018 May 5;196:40-48. doi: 10.1016/j.saa.2018.02.001. Epub 2018 Feb 2.
The use of printers to generate falsified documents has become a common practice in today's world. The examination and identification of the printed matter in the suspected documents (civil or criminal cases) may provide important information about the authenticity of the document. In the present study, a total number of 100 black toner samples both from laser printers and photocopiers were examined using diffuse reflectance UV-Vis Spectroscopy. The present research is divided into two parts; visual discrimination and discrimination by using multivariate analysis. A comparison between qualitative and quantitative analysis showed that multivariate analysis (Principal component analysis) provides 99.59%pair-wise discriminating power for laser printer toners while 99.84% pair-wise discriminating power for photocopier toners. The overall results obtained confirm the applicability of UV-Vis spectroscopy and chemometrics, in the nondestructive analysis of toner printed documents while enhancing their evidential value for forensic applications.
在当今世界，利用打印机生成伪造文件已成为一种常见做法。对可疑文件（民事或刑事案件）中的印刷品进行检查和鉴定，可能会提供有关文件真实性的重要信息。在本研究中，使用漫反射紫外可见光谱法对来自激光打印机和复印机的总共100个黑色墨粉样本进行了检查。本研究分为两个部分：视觉鉴别和使用多变量分析进行鉴别。定性分析和定量分析的比较表明，多变量分析（主成分分析）对激光打印机墨粉的成对鉴别能力为99.59%，对复印机墨粉的成对鉴别能力为99.84%。所获得的总体结果证实了紫外可见光谱法和化学计量学在墨粉打印文件无损分析中的适用性，同时提高了它们在法医应用中的证据价值。
