气相色谱法确定蓝色圆珠笔油墨字迹的形成时间

Determination of the Writing Age of Blue Ballpoint Ink by Gas Chromatography

选择适当的内标物,利用气相色谱法测定蓝色圆珠笔油墨中展色剂苯甲醇和苯氧基乙醇这两种组分的含量(以峰面积计),以展色剂的峰面积、内标物的峰面积与紫外 可见光谱测得的参比物墨水中的染料的吸光度值这三者之比为纵坐标,以字迹形成时间为横坐标,确定了字迹形成曲线,从而建立了确定字迹形成时间的方法。选择了不同种类的蓝色圆珠笔油墨进行检测,获得了良好的实验效果,为圆珠笔油墨字迹形成时间的推断建立了一种可靠而又系统的方法。该方法适用于实际办案。

A method of identifying the writing age of blue ballpoint ink has been established for imperative demand of forensic laboratory. The content of the volatile component in blue ballpoint ink was determined by gas chromatography (GC). The absorbance of the dye in the blue ballpoint ink was measured by ultraviolet-visible spectrometry (UV-Vis). A writing age curve of the blue ballpoint ink has been established by the ratio of the content of the volatile components and the dye, based on the identification of 74 kinds of blue ballpoint inks, from both domestic and international origins. The change of benzyl alcohol or phenoxyethyl alcohol was tested with the writing age. Blue ballpoint inks of different kinds were detected and the repeatability of the experiment was investigated. The results indicated that the method is reliable and systematic, and especially suitable for practical cases.