Applications of paper spray ionization mass spectrometry in forensic science: A mini review.

This article reviews the development and forensic applications of Paper Spray Ionization Mass Spectrometry (PSI-MS), an ambient ionization technique introduced in 2009 that enables rapid, sensitive analysis of trace forensic samples with minimal preparation. PSI-MS has been applied across diverse forensic domains including biomolecule detection, drug and narcotic identification, ink and document examination, explosives analysis, and chemical warfare agent (CWA) detection, demonstrating compatibility with various sample types such as dried blood spots, biofluids, and surface residues. Advances in substrate materials, such as carbon fiber paper and nanomaterial-impregnated papers, have enhanced sensitivity and broadened analyte detection, while integration with portable mass spectrometers supports on-site forensic analysis. The technique offers advantages over traditional methods like liquid chromatography-mass spectrometry (LC-MS) by requiring smaller sample volumes, providing rapid results, and enabling cost-effective, user-friendly operation, positioning PSI-MS as a promising tool for forensic and clinical laboratories.