基于拉曼光谱鉴定黑色签字笔笔迹的种类与书写时间

doi:10.3964/j.issn.1000-0593(2020)04-1156-06

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摘要：黑色签字笔字迹种类与书写时间的鉴定一直是国内外法庭科学研究领域的热点问题。基于拉曼光谱法的分辨率高、稳定性好、效率高以及无损检测等优点，对收集的16种品牌或牌号的黑色签字笔字迹样本进行测试。完成同一品牌或牌号同一时间在不同存储条件（暗室和光照）与不同纸张本底（复印纸和笔记本）字迹样本的制备。将样本字迹剪裁，双面胶固定在载玻片上，放入储存箱内避光保存，间隔一段时间对样品进行测试，测试工作共持续1年，形成图谱数据库。在考察实验条件如测量点、激光功率及共焦类型等因素影响的基础上，筛选出最佳条件。在此条件基础上，检测黑色签字笔在不同书写时间、储存环境、纸张本底等条件下的字迹样本。实验结果表明：(1)存储条件（暗室和光照）、纸张本底（复印纸和笔记本）等不同条件下，同种黑色签字笔字迹的拉曼位移相同，重复性好，受水和纸张等本底的干扰较小。(2)根据拉曼位移的差异可将16种黑色签字笔分成5类。(3)以2^#样本为例，1 140 cm^-1处拉曼光谱特征峰，归属为酯类化合物的C—O伸缩振动ν(CO)。酯类化合物的含量随着时间延长而不断减少，因此随着书写时间越久远，特征峰的相对强度越大(8→1)。通过拟合后计算出相对面积数值I，样本书写时间越早，I值越大，反之I值越小。研究结果可用于快速、准确、无损判定黑色签字笔字迹的种类和推断其相对书写时间。

关键词：黑色签字笔；书写时间；拉曼光谱；种类；无损检测

Abstract：The identification of the type and the writing time of black signature pen handwriting has always been a hot topic in the field of forensic science at home and abroad. Based on the advantages of Raman spectroscopy, such as high resolution, good stability, high efficiency and nondestructive testing, 16 brands of black signature pen handwriting samples were tested. The samples of the same brand at the same time with different storage conditions (darkroom and lighting) and different paper background (copy paper and notebook) handwriting samples were completed. The handwriting samples were clipped and fixed on the glass slide with the double-sided adhesive, and stored in the storage box to protect them from light, and then the samples were tested at intervals. The test lasted for one year to form a Raman spectrum database. The optimum conditions were selected based on the investigation of the influence of experimental conditions, such as measuring point, laser power and confocal type. Based on the optimum conditions, the handwriting samples of black signature pen were determined under different writing time, storage environment and paper background. The experimental results indicated that: (1) Under different conditions of storage conditions (darkroom and lighting) and paper background (copy paper and notebook), the same kind of black signature pen handwriting had the same Raman shift, and the repeatability was good, indicating the less disturbance by the background of water and paper. (2) According to the Raman shift, 16 types of black signature pen could be classified into five categories. (3) Taking 2^# sample as example, a characteristic peak of Raman spectrum at 1 140 cm^-1 was assigned to the C—O stretching vibration ν(CO) of the ester compound, the content of which decreasing over time. Therefore, the relative intensity of the characteristic peak was increased with the writing time (8→1). The relative area value I was calculated by the fitting method, and it indicated that the I value was increased with the writing time of the sample. Our strategy can be applied in quick and nondestructive determination of the types and relative writing times of the black signature pen handwriting.

Key words：Black signature pen; Writing time; Raman spectroscopy; Type; Non-destructive detection

收稿日期: 2019-03-08 修订日期: 2019-07-17

中图分类号:

O657.37

基金资助: 国家自然科学基金项目（201805208），河南省科技计划项目（科技攻关）（172102210112, 172102310603），河南省高等学校重点科研资助项目（16A150041）资助

作者简介: 万敬伟，1987年生，铁道警察学院刑事科学技术系副教授 e-mail: wanjingwei@rpc.edu.cn

引用本文:

万敬伟，崔胜峰，陈蕾，马学兵. 基于拉曼光谱鉴定黑色签字笔笔迹的种类与书写时间[J]. 光谱学与光谱分析, 2020, 40(04): 1156-1161.
WAN Jing-wei, CUI Sheng-feng, CHEN Lei, MA Xue-bing. Identification of the Types and Writing Time of Black Signature Pen Handwriting Based on Raman Spectroscopy. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2020, 40(04): 1156-1161.

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