Microscopy With Direct Analyte Probe Nanoextraction (DAPNe)-Coupled to Nanospray Mass Spectrometry for Localized Chemical Analysis of Document Inks

This new and innovative technique does not leave destructive remnants on the surface of a document. As proof of concept, analysis of inks from various eras was conducted, along with the capability to detect the oxidative products of polyethylene glycol (PEG), a common binding agent in India inks. The experimental results indicate that DAPNe-NSI-MS can chelate iron and manganese ions of iron gall ink and organic components of modern and carbon-based inks. This new approach can identify and characterize the ingredients by modifying the extraction solvent, illustrating the potential diversity of the extraction chemistries. DAPNe also has been coupled to Raman spectroscopy, fluorescence microscopy, and NDI-MS to determine whether an ink entry on a document was falsified. In order to establish the proof of concept, reproducibility, sensitivity, and qualitative and quantitative nature, the developed techniques will be used for forensic science trace analysis on paint, ink, and trace document residue from transfer. This will demonstrate the versatility of the technique. 15 figures, 4 tables, 68 references, and a listing of disseminated presentations