title: Distinguishing authentic and counterfeit banknotes by surface chemical composition determined using electrospray laser desorption ionization mass spectrometry.
abstract: Electrospray laser desorption ionization mass spectrometry (ELDI/MS) was used to rapidly distinguish authentic banknotes from counterfeits of the US dollar and the New Taiwan dollar. The banknotes' surfaces were irradiated with a pulsed ultraviolet laser, after which the desorbed ink compounds entered an electrospray plume and formed ions via interactions with charged solvent species. Authentic banknotes were found to differ from their counterfeit equivalents in their surface chemical compositions. The detected chemical compounds included various polymers, plasticizers and inks; these results were comparable with those obtained using solvent extraction followed by electrospray ionization mass spectrometry analysis. Because of the high spatial resolution of the laser beam, ELDI/MS analysis resulted in minimal damage to the banknotes.
authors.affiliation: College of Pharmacy, Taipei Medical University, Taipei, Taiwan; Investigation Bureau, Ministry of Justice, New Taipei, Taiwan.
authors.forename: Yi-Ying
authors.initials: YY
authors.lastname: Kao
authors.forename: Chu-Nian
authors.initials: CN
authors.lastname: Cheng
authors.forename: Sy-Chyi
authors.initials: SC
authors.lastname: Cheng
authors.forename: Hsiu-O
authors.initials: HO
authors.lastname: Ho
authors.forename: Jentaie
authors.initials: J
authors.lastname: Shiea
keywords: ambient mass spectrometry; banknote; electrospray laser desorption ionization; money counterfeiting; principal component analysis