摘要
基于溶剂挥发原理,采用气相色谱-质谱法(GC-MS)和气相色谱法-氢火焰离子检测器(GC-FID)对黑色中性笔历时性字迹样本中的甘油、二甘醇、三甘醇溶剂含量进行测定,并绘制了3种溶剂的含量随书写时间变化的关系曲线(字迹的老化曲线)。利用GC-MS从196种市购黑色中性笔中筛选出分别以甘油、二甘醇、三甘醇为主要溶剂的9支黑色中性笔,比照直尺在A4纸上画线,每只笔制作3个样本,每个月制作一次样本,连续收集21个月的样本,室温保存在封闭抽屉中。用直径为0.5 mm的打孔器在每张A4纸上取10个墨迹点,用含5 mg·L^(-1)苯甲酸乙酯(内标物)的甲醇溶液提取其中的溶剂,提取液进入GC-FID,吸附在DB-FFAP色谱柱上的溶剂在程序升温条件下分离,用FID测定。配制50 mg·L^(-1)混合标准溶液用于单点法定量,以书写时间为横坐标,其对应的单位书写长度中的溶剂的质量为纵坐标绘制字迹的老化曲线。结果显示,每个中性笔字迹中溶剂的初始含量各不相同,但每种溶剂含量随书写时间变化的拐点基本相同,甘油、二甘醇、三甘醇的含量分别在第7个月、第3个月、第9个月左右出现拐点,拐点之后溶剂含量趋于13,3,7 ng·mm^(-1)。方法用于一起实际案例(收条真伪鉴定)的分析,在涉及的2张收条中分别检出了20,34 ng·mm^(-1)的甘油,表明2张收条都是近期伪造的。
Based on the principle of solvent volatilization, the solvent components of glycerol, diethylene glycol and triethylene glycol in diachronic handwriting samples of black gel pen were determined by GC-MS and GC-FID, and the curves(aging curves of handwriting) of the contents of 3 solvents with writing time were drawn. Nine black gel inks with glycerol, diethylene glycol and triethylene glycol as the main solvents were selected from 196 kinds of black gel pens purchased in the market by GC-MS. The pen was used to draw lines on A4 paper against a ruler. Three samples were made for each pen once a month, and the samples for 21 consecutive months were collected and stored in a closed drawer at room temperature. Ten ink spots were taken from each A4 paper with a punch at a diameter of 0.5 mm, and the solvent was extracted by methanol solution containing 5 mg·L^(-1) ethyl benzoate(internal standard). The extract was introduced into GC-FID, and the solvents adsorbed on the DB-FFAP chromatographic column were separated under the temperature programmed condition and detected by FID. 50 mg·L^(-1) mixed standard solution was prepared for quantification by single point method. Aging curves of handwriting were drawn with writing time as abscissa and the mass of solvent in the corresponding unit writing length as ordinate. The results showed that the initial contents of solvents in each black gel pen handwriting were different, but the inflection points of each solvent content changing with writing time were basically the same. The contents of glycerol, diethylene glycol and triethylene glycol showed inflection points around the seventh month, the third month and the ninth month, respectively. After the inflection point, the solvent contents tended to 13, 3, 7 ng·mm^(-1). The proposed method was used to analyze a real case(authenticity identification of the receipt), and 20, 34 ng·mm^(-1) glycerol was detected in the two receipts, which turned out that both receipts were recently forged.
作者
何海洋
赵鹏程
何宁
倪云昌
李泽瀚
HE Haiyang;ZHAO Pengcheng;HE Ning;NI Yunchang;LI Zehan(College of Forensic Science,Criminal Investigation Police University of China,Shenyang 110035,China;Key Laboratory of Evidence Laiv and Forensic Science,Ministry of Education,China University of Political Science and Lazv,Beijing 100088,China)
出处
《理化检验（化学分册）》
CAS
CSCD
北大核心
2021年第9期769-775,共7页
Physical Testing and Chemical Analysis(Part B:Chemical Analysis)
基金
公安部科技强警基础工作专项基金(2019GABJC03)。
