共焦显微拉曼光谱技术在墨迹鉴定方面的应用

利用共焦显微拉曼光谱技术,用可见514.5nm和紫外325nm激光器作激发光源,分别测试了不同品牌的黑色圆珠笔,蓝色圆珠笔和黑色签字笔墨迹的拉曼谱图。在可见514.5nm激光器的激发下,黑色和蓝色圆珠笔墨迹都呈现了丰富的拉曼特征峰而黑色签字笔仅出现了碳峰的信号;此时改换325nm激光器来激发,发现黑色签字笔墨迹出现了清晰的拉曼特征谱峰。通过实验数据对比发现:同一类型且不同品牌笔的墨迹拉曼特征谱峰也存在一定的差异,同一种品牌墨迹的拉曼峰都保持了相对的稳定性。实验结果将为鉴定签字笔和圆珠笔油墨种类提供了法庭科学依据。它的最大优点就在于对样品的无损性,其次还有快速、无需对样品预处理和测试方法简单等。

Applications of micro-Raman technique on the identification of ink marks

The Raman spectra of different brands' ink marks by spectroscopic technique were measured.All Raman spectra were excited with 325nm and 514.5nm radiation.With 514.5nm radiation,the ink marks of black and blue ball pen have a lot of Raman spectra,but the Raman spectra of the gel ink pens only have bands of carbon.At the same time,tuned to 325nm as the exciting line,lots of clear Raman spectra appeared.It is indicated that the distinctiveness of Raman spectra of ink marks of the same kind and different brand's pens existed.The results will offer scientific evidence to court for identifying the types of ink marks and provide stronger proofs for the commits such as altering the signatures in the contracts.The advantages of the methods are high-speed,simple and no need for pretreatment,particularly,its non-destructiveness.