► Degradation of the dye components in ink entries has been investigated by LDI-MS.► Dating method for the ink entries were developed based on degradation of the dyes.The approaches for differentiation and dating of gel pen ink entries have been investigated by laser desorption ionization-time of flight mass spectrometry (LDI-TOF-MS) and high performance liquid chromatography-quadruple-time of flight mass spectrometry (HPLC-Q-TOF-MS).
The results showed that the variations of relative intensities for the main dye components have a close relationship with aging time, and the degradation of the main dye components were significant under natural storage conditions, which can provide important evidences for dating of the ink entries on paper.► The gel pen ink entries have been differentiated by LDI-TOF-MS.
► The dye components of the ink entries have been identified by Q-TOF-MS.
Allied Military Currency(AMC) -money issued by Allied military authority(USA, UK, Russia and France) during and after the World War II in following countries: Austria, Denmark, France, Germany, Italy, Japan. The contemporary counterfeits were made by Governments or private persons to pass side by side with genuine notes.
Modern counterfeits were made to fool collectors (it is virtually an unknown problem in paper money collecting, with exceptions of overprints, additional stamps or very poorly unsecured printed emergency notes) Specimens -samples of original banknotes distributed between banks to familiarize with new designed banknotes, usually with overprints, cancellation or special numbers.
As the ancient Greek scientist Archimedes is said to have said from his bath: Eureka!