Rapid identification of illegal drugs and explosives using resonance excitation in miniaturized photoionization ion trap mass spectrometry

Abstract

Illegal drugs and the explosives are harmful chemicals that present both social and national security issues. Existing analytical instruments and methods for identifying these substances are constrained by sensitivity, speed, and portability because of inherent technical defects. Miniaturized photoionization ion trap mass spectrometry is suitable for rapid and on-site identification of illegal drugs and the explosives; however, tandem mass spectrometry and the fragment ions have not been fully investigated. In this article, the abundant fragments of 22 illegal drugs and seven explosives were analyzed successfully using resonance excitation with a miniaturized ion trap mass spectrometer constructed in our laboratory and coupled with flash-thermal-desorption acetone-assisted photoionization. The mass range of the rectilinear ion trap was optimized through experimental mapping of stability diagrams to decrease the effect of the low mass cut-off. The secular frequencies for resonance excitation were simulated and validated using the experimental results. The fragments of illegal drugs and explosives were investigated and imported into a database. By comparing the tandem mass spectrometry fragments and the created database, a seized analyte could be identified within 3 s using a single analysis. This work indicates that ion resonance excitation is an effective approach for rapid analysis of illegal drugs and explosives. Furthermore, combination of a miniaturized ion trap mass spectrometer and compound database is useful for the identification of unknown and known compounds in forensic screening applications.