Depth profiling of inks in authentic and counterfeit banknotes by electrospray laser desorption ionization/mass spectrometry

Abstract

Electrospray laser desorption ionization is an ambient ionization technique that generates neutrals via laser desorption and ionizes those neutrals in an electrospray plume and was utilized to characterize inks in different layers of copy paper and banknotes of various currencies. Depth profiling of inks was performed on overlapping color bands on copy paper by repeatedly scanning the line with a pulsed laser beam operated at a fixed energy. The molecules in the ink on a banknote were desorbed by irradiating the banknote surface with a laser beam operated at different energies, with results indicating that different ions were detected at different depths. The analysis of authentic $US100, $100 RMB and $1000 NTD banknotes indicated that ions detected in 'color-shifting' and 'typography' regions were significantly different. Additionally, the abundances of some ions dramatically changed with the depth of the aforementioned regions. This approach was used to distinguish authentic $1000 NTD banknotes from counterfeits. Copyright © 2015 John Wiley & Sons, Ltd.

Fluorescence of Selected Polymer Banknotes

“…Counterfeiting of classic paper banknotes is not quite easy as no commonly available paper is used for their production [4]. At first glance and during a quick exchange of money, a counterfeit printed on a quality printer may be indistinguishable from the original banknote [5], [6], [7], [8]. Although with the abolition of the so-called gold standard and with the spread of modern payment technologies (payment cards, internet banking, cryptocurrencies) the importance of physical money is declining, they are still in some way irreplaceable [2].…”

“…Microscopy and non-destructive methods such as Raman spectroscopy, FT-IR and X-ray fluorescence are commonly used to identify counterfeit banknotes [5], [12], [13], [14]. Destructive methods, such as gas chromatography and mass spectrometry, can also be used [6], [11]. In particular, the characteristics of the individual features of the banknotes and their possible applicability for the detection of counterfeits are examined for example in: [15] for historical banknotes, [5], [6], [7], [8], [12], [16] for paper banknotes and [13], [17] for polymer banknotes.…”

“…Destructive methods, such as gas chromatography and mass spectrometry, can also be used [6], [11]. In particular, the characteristics of the individual features of the banknotes and their possible applicability for the detection of counterfeits are examined for example in: [15] for historical banknotes, [5], [6], [7], [8], [12], [16] for paper banknotes and [13], [17] for polymer banknotes. These methods can also be used for the analysis of printing on polymer [18].…”

Direct determination of trace phthalate esters in alcoholic spirits by spray‐inlet microwave plasma torch ionization tandem mass spectrometry

“…In the last decade, atmospheric pressure ionization mass spectrometry has developed into a new kind of analytical method, and ambient ionization sources, namely, desorption electrospray ionization, electrospray laser desorption ionization, extractive electrospray ionization (EESI), low‐temperature plasma, direct analysis in real time, and air‐flow‐assisted ionization are possible choices for the rapid analysis of complex samples without pretreatment. The microwave plasma torch (MPT) is a recently developed microwave plasma‐based ambient ionization source with many advantages, such as miniaturization, excellent ionization efficiency, and strong excitation ability.…”

Rapid analysis of forensic‐related samples using two ambient ionization techniques coupled to high‐resolution mass spectrometers

“…[1] Within the past decade, there has been an escalation in the development of ambient ionization techniques, which are easily adaptable for small molecules, and in some cases have considerably reduced sample preparation time. Ambient ionization techniques can be grouped into two major categories: ESI-based techniques, which include desorption electrospray ionization (DESI), [2][3][4][5][6][7] electrospray laser desorption ionization (ELDI), [8][9][10] matrix-assisted laser desorption electrospray ionization (MALDESI), [11][12][13] and paper spray ionization (PSI), [7,14,15] and atmospheric pressure chemical ionization (APCI)-based ambient ionization techniques, which include atmospheric solids analysis probe (ASAP), [16][17][18][19] desorption atmospheric pressure chemical ionization (DAPCI), [20][21][22] direct analysis in real time (DART), [23][24][25][26] and laser diode thermal desorption (LDTD), [27][28][29][30] among others. [31] Ambient techniques offer several advantages over more traditional ionization techniques such as ESI.…”