Department of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, UK.
Spectrochim Acta A Mol Biomol Spectrosc. 2014 Jan 24;118:1158-63. doi: 10.1016/j.saa.2013.09.115. Epub 2013 Oct 12.
Bank of England notes of £20 denomination have been studied using infrared spectroscopy in order to generate a method to identify forged notes. An aim of this work was to develop a non-destructive method so that a small, compact Fourier transform infrared spectrometer (FT-IR) instrument could be used by bank workers, police departments or others such as shop assistants to identify forged notes in a non-lab setting. The ease of use of the instrument is the key to this method, as well as the relatively low cost. The presence of a peak at 1400 cm(-1) arising from νasym (CO3(2-)) from the blank paper section of a forged note proved to be a successful indicator of the note's illegality for the notes that we studied. Moreover, differences between the spectra of forged and genuine £20 notes were observed in the ν(OH) (ca. 3500 cm(-1)), ν(C-H) (ca. 2900 cm(-1)) and ν(C=O) (ca. 1750 cm(-1)) regions of the IR spectrum recorded for the polymer film covering the holographic strip. In cases where these simple tests fail, we have shown how an infrared microscope can be used to further differentiate genuine and forged banknotes by producing infrared maps of selected areas of the note contrasting inks with background paper.
我们使用红外光谱法研究了面值为 20 英镑的英格兰银行纸币，旨在开发一种鉴别伪造纸币的方法。这项工作的目的之一是开发一种非破坏性的方法，以便银行工作人员、警察部门或其他人员（如店员）能够在非实验室环境中使用小型、紧凑的傅里叶变换红外光谱仪（FT-IR）仪器来识别伪造纸币。该方法的关键在于仪器的易用性以及相对较低的成本。伪造纸币空白部分的 νasym (CO3(2-)) 引起的 1400cm(-1) 处的峰的存在被证明是该纸币非法的成功指标，对于我们研究的纸币来说确实如此。此外，在记录聚合物膜覆盖全息条的 IR 光谱的 ν(OH)（约 3500cm(-1))、ν(C-H)（约 2900cm(-1)) 和 ν(C=O)（约 1750cm(-1)) 区域中，观察到伪造和真 20 英镑纸币之间的光谱存在差异。在这些简单测试失败的情况下，我们展示了如何使用红外显微镜通过产生与背景纸张形成对比的选定纸币区域的油墨的红外图谱来进一步区分真假纸币。
