The differentiation and relative dating of ink lines in questioned documents are important tasks in forensic science. Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) is a surface-sensitive mass spectrometry technique with potential to distinguish inks based on chemical differences such as those caused by differences in the age of ink markings from the same pen. In this work, both positive and negative polarity ToF-SIMS spectra were evaluated for three commercial black ballpoint pen inks over an analysis time of 4 to 671 days. Changes in the spectra included demethylation of triarylmethane dyes such as crystal violet, and loss of the anionic dye metanil yellow. ToF-SIMS spectra of the black ballpoint inks continued to change up to 6 months for all inks and up to 22 months in some cases. Samples with 1-day, 1-week and 1-month drying times were also evaluated using several data processing approaches. Markings from the same pen were most likely to be distinguished by ToF-SIMS if the age difference between the markings was 1 month or longer, although some samples were distinguished with smaller differences in writing times. Furthermore, the results indicated that ToF-SIMS imaging is best performed within 3–6 months after sample preparation as differentiation becomes more difficult after longer analysis delays. This is the first systematic ToF-SIMS study of ink aging, which provides valuable information about the characteristic ions and data analysis approaches for future forensic analyses.

质疑文档中墨线的区分和相对日期是法医学中的重要任务。飞行时间二次离子质谱（ToF-SIMS）是一种表面敏感质谱技术，具有根据化学差异（例如由同一支笔的墨水标记年龄不同引起的化学差异）区分墨水的潜力。在这项工作中，在4至671天的分析时间内，对三种商用黑色圆珠笔墨水的正负极性ToF-SIMS光谱进行了评估。光谱的变化包括三芳基甲烷染料（例如结晶紫）的去甲基化，以及阴离子染料间甲黄的损失。黑色圆珠笔墨水的ToF-SIMS光谱在所有墨水中持续变化长达6个月，在某些情况下长达22个月。1天的样品，还使用几种数据处理方法评估了1周和1个月的干燥时间。如果标记之间的年龄差异为1个月或更长时间，则ToF-SIMS最有可能区分来自同一笔的标记，尽管有些样品的书写时间差异较小。此外，结果表明，ToF-SIMS成像最好在样品制备后的3–6个月内执行，因为较长的分析延迟后区分变得更加困难。这是首次对油墨老化进行系统的ToF-SIMS研究，它提供了有关特征离子的有价值的信息以及用于未来法医分析的数据分析方法。如果标记之间的年龄差异为1个月或更长时间，则ToF-SIMS最有可能区分来自同一笔的标记，尽管有些样品的书写时间差异较小。此外，结果表明，ToF-SIMS成像最好在样品制备后的3–6个月内执行，因为较长的分析延迟后区分变得更加困难。这是首次对油墨老化进行系统的ToF-SIMS研究，它提供了有关特征离子的有价值的信息以及用于未来法医分析的数据分析方法。如果标记之间的年龄差异为1个月或更长时间，则ToF-SIMS最有可能区分来自同一笔的标记，尽管有些样品的书写时间差异较小。此外，结果表明，ToF-SIMS成像最好在样品制备后的3–6个月内执行，因为较长的分析延迟后区分变得更加困难。这是首次对油墨老化进行系统的ToF-SIMS研究，它提供了有关特征离子的有价值的信息以及用于未来法医分析的数据分析方法。结果表明，ToF-SIMS成像最好在样品制备后3–6个月内进行，因为较长的分析延迟会导致分化变得更加困难。这是首次对油墨老化进行系统的ToF-SIMS研究，它提供了有关特征离子的有价值的信息，并为将来的法医分析提供了数据分析方法。结果表明，ToF-SIMS成像最好在样品制备后3–6个月内进行，因为较长的分析延迟会导致分化变得更加困难。这是首次对油墨老化进行系统的ToF-SIMS研究，它提供了有关特征离子的有价值的信息以及用于未来法医分析的数据分析方法。