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Investigation of Falsified Documents via Direct Analyte-Probed Nanoextraction Coupled to Nanospray Mass Spectrometry, Fluorescence Microscopy, and Raman Spectroscopy

NCJ Number
Analyst Volume: 140 Dated: 2015 Pages: 6553-6562
Date Published
10 pages
This article reports on a study in which direct analyte-probed nanoextraction (DAPNe) was coupled to Raman spectroscopy, fluorescence microscopy, and nanospray ionization mass spectrometry (NSI-MS) to determine whether an ink entry from a document was falsified.

Microscopy with direct analyte-probed nanoextraction coupled to nanospray ionization mass spectrometry (DAPNe-NSI-MS) is a direct extraction technique that extracts ultra-trace amounts of analyte. It has been proven to extract ink from documents with little to no physical or chemical footprint. In the current study, a handwritten number was altered using a different ink pen to test whether the aforementioned techniques could discriminate the original number from the altered number, qualitatively and/or quantitatively. Chemical species from part of the original number, altered number, and a point at which both inks intersect were successfully differentiated by all techniques when using different pens. DAPNe coupled to fluorescence microscopy and Raman spectroscopy was not able to discriminate the forged ink entry when the exact same pen was used to modify the text (due to the same ink formula); however, DAPNe-NSI-MS successfully discerned that the pen was dispensed on different days by quantitating the oxidation process. (publisher abstract modified)

Date Published: January 1, 2015