Applications of electrospray laser desorption ionization mass spectrometry for document examination |
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Authors: | Sy‐Chyi Cheng Yu‐Shan Lin Ming‐Zong Huang Jentaie Shiea |
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Institution: | 1. Department of Chemistry, National Sun Yat‐Sen University, Kaohsiung, Taiwan;2. Forensic Science Center, Kaohsiung City Government Police Bureau, Kaohsiung, Taiwan;3. National Sun Yat‐Sen University‐Kaohsiung Medical University Joint Research Center, Kaohsiung, Taiwan |
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Abstract: | We have employed electrospray laser desorption ionization mass spectrometry (ELDI‐MS) to rapidly characterize certain classes of compounds – the inks within the characters made by inks and inkjet printer on regular paper and the chemical compounds within thermal papers. This ELDI‐MS approach allowed the ink and paper samples to be distinguished in terms of their chemical compositions. Sample pretreatment was unnecessary and the documents were practically undamaged after examination. The ink chemicals on the documents were desorbed through laser irradiation (sampling spot area: <100 µm2); the desorbed molecules then entered an electrospray plume – prepared from an acidic methanol/water solution (50%) – where they became ionized through fusion or ion‐molecule reactions with the charged solvent species and droplets in the plume. Copyright © 2009 John Wiley & Sons, Ltd. |
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