Applications of electrospray laser desorption ionization mass spectrometry for document examination.
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 microm(2)); 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.
Cheng
Sy-Chyi
SC
Department of Chemistry, National Sun Yat-Sen University, Kaohsiung, Taiwan.
Lin
Yu-Shan
YS
Huang
Ming-Zong
MZ
Shiea
Jentaie
J
D004867:Equipment Design; D007281:Ink; D010209:Paper; D021241:Spectrometry, Mass, Electrospray Ionization / Q000191:economics / Q000295:instrumentation / Q000379:methods*