Abstract
A mixed solution of 28% of ammonia and pyridine (9 : 1 (v/v)) was used to extract dye ink from counterfeit paper money printed by an ink-jet printer. The counterfeit paper money was fixed on a vacuum filtration device instead of a membrane filter. The extracted solution was collected in a test tube and was evaporated to dryness under reduced pressure in a 40°C water bath. The extract was dissolved by 10 μl of the extraction solution and spotted on a silica gel plate. The silica gel plate was developed by iso-propanol : 28% ammonia : pyridine (2 : 9 : 1 v/v/v). By comparison with TLC patterns, we could clearly distinguish among the various printer companies. Furthermore the TLC pattern was discriminated between the machine types to some extent.
