ThoMSon Mass Spectrometry Laboratory, Institute of Chemistry, University of Campinas-UNICAMP, 13084-970 Campinas, SP, Brazil.
Analyst. 2010 Apr;135(4):745-50. doi: 10.1039/b923398a. Epub 2010 Feb 2.
Using easy ambient sonic-spray ionization mass spectrometry (EASI-MS), fast and non-destructive fingerprinting identification and aging of ballpoint pen ink writings have been performed directly from paper surfaces under ordinary ambient conditions. EASI-MS data obtained directly from the ink lines showed that pens from different brands provide typical ink chemical profiles. Accelerated ink aging has also been monitored by EASI-MS revealing contrasting degradation behaviors for six different common ink dyes. As demonstrated for Basic Violet 3, some dyes display a cascade of degradation products whose abundances increase linearly with time thus functioning as 'chemical clocks' for ink aging. Analysis of questionable documents has confirmed the ink aging capabilities of EASI-MS. The order of superimposition at a crossing point has also been determined by EASI-MS. For two superimposed ink lines, continuous EASI-MS analysis has also shown that the EASI spray is able to penetrate through the layers and therefore both ink layers could be characterized.
使用简单环境声喷雾电离质谱（EASI-MS），可以在普通环境条件下直接从纸面上快速、无损地对圆珠笔墨水的指纹进行识别和老化分析。从墨迹中直接获得的 EASI-MS 数据表明，不同品牌的笔提供了典型的墨水化学特征。EASI-MS 还监测到了加速的墨水老化，结果显示六种常见的墨水染料具有不同的降解行为。如 Basic Violet 3 所示，一些染料显示出一系列降解产物，其丰度随时间线性增加，因此可作为墨水老化的“化学时钟”。对有疑问的文件的分析也证实了 EASI-MS 的墨水老化能力。在交叉点处的叠加顺序也通过 EASI-MS 确定。对于两条叠加的墨迹线，连续的 EASI-MS 分析也表明，EASI 喷雾能够穿透墨层，因此可以对两层墨水进行特征分析。
