Chemical Analysis and Imaging of Fingerprints by Air-flow Assisted Desorption Electrospray Ionization Mass Spectrometry

Abstract Fingerprint analysis is of great significance in forensic sciences. Compared with existing fingerprint analytical methods, mass spectrometry-based methods can not only identify chemical components in fingerprints, but also obtain fingerprint imaging. In this study four kinds of fingerprints, including sweat, inkpad, sunscreen, and liquid foundation, were analyzed by air-flow assisted desorption electrospray ionization mass spectrometry imaging (AFADESI-MSI). AFADESI was employed with air flow of 45 L min−1, and 5 μL min−1 acetonitrile was used as spray solvent at spray voltage of 7000 V. Positive ion full scan mode (100−1000 Da) was chosen. The results showed that AFADESI-MSI method could not only obtain chemical information of various endogenous and exogenous substances in fingerprints, but also obtain high resolution images of fingerprints. In addition, overlapped fingerprints were distinguished according to the typical chemical information in fingerprints. As a new fingerprint analysis method, AFADESI-MSI would be widely used in forensic scientific research and practical applications.