Direct Analyte-Probed Nanoextraction (DAPNe) Coupled to Matrix-Assisted Laser Desorption Ionization (MALDI) for Examination of the Ink Chemistry on Documents

DAPNe was first used to extract ink from the document and then deposit the sample on the MALDI plate. Through this method, cutting the document for MALDI-MS analysis was avoided. DAPNe extracted ink from documents with minimal to no visible destruction. Specific dyes and binding agents in the extracted ink were monitored with mass spectrometry. Different matrices, 1, 5-diaminonapthalene (DAN), 2, 5-dihydroxybenzoic acid (DHB), and silver nanoparticles, were tested to compare intensity enhancement of the mass spectra signals. The advantages of using MALDI-MS coupled to DAPNe were shown by characterizing Crystal Violet, Basic Yellow 2, Rhodamine B, and polyethylene glycol from red and blue pens, black pen, and a black inkjet printer cartridge. (publisher abstract modified)