Explosive detection using a novel dielectric barrier discharge ionisation source for mass spectrometry

Abstract

The detection of explosives is of great importance, as is the need for sensitive, reliable techniques that require little or no sample preparation and short run times for high throughput analysis. In this work, a novel ionisation source is presented based on a dielectric barrier discharge (DBD). This not only affects desorption and ionisation but also forms an ionic wind, providing mass transportation of ions towards the mass spectrometer. Furthermore, the design incorporates 2 asymmetric alumina sheets, each containing 3 DBDs, so that a large surface area can be analysed. The DBD operates in ambient air, overcoming the limitation of other plasma-based techniques which typically analyse smaller surface areas and require solvents or gases. A range of explosives across 4 different functional groups was analysed using the DBD with low limits of detection for cyclotrimethylene trinitramine (RDX) (100 pg), pentaerythritol trinitrate (PETN) (100 pg), hexamethylene triperoxide diamide (HMTD) (1 ng), and trinitrotoluene (TNT) (5 ng). Detection was achieved without any sample preparation or the addition of reagents to facilitate adduct formation.

Detection of Trace Explosives Using a Novel Sample Introduction and Ionization Method

“…The development of ambient ionization techniques has promoted the application of mass spectrometry in the field of on-site rapid explosives detection [ 8 ]. Plenty of ambient ionization sources have been proposed for direct sampling and ionization of explosives under ambient conditions, such as desorption electrospray ionization (DESI) [ 9 , 10 ] and direct analysis in real time (DART) [ 11 , 12 ], low temperature plasma (LTP) [ 13 , 14 , 15 , 16 ] or dielectric barrier discharge ionization (DBDI) [ 17 , 18 , 19 , 20 ], atmospheric pressure chemical ionization (APCI) [ 21 , 22 ], photoionization (PI) [ 23 , 24 ], paper spray ionization (PSI) [ 25 , 26 ], and so on. However, most of these methods normally involve the use of expensive and specialized consumables such as solvent, dopant, and inert gas, which should be avoided in field applications.…”