Development of Unidirectional Negative Corona Discharge Ion Mobility Spectrometer for Detection of Explosives / 分析化学

ABSTRACT

Abstract Ion mobility spectrometry ( IMS) based explosives detectors is wieldy deployed at the check points of airport, etc, so the development of new ionization method to replace the radioactive 63 Ni ion source in IMS is highly demanded. In this study, a novel negative corona discharge was developed for ion mobility spectrometer for rapid detection of trace explosives, which was running in the unidirectional mode to efficiently remove nitrogen oxides and ozone produced from the discharge process. The diameter of target electrode was 3 mm, the distance between the needle and the target electrode was 2 mm, the discharge voltage was 2400 V and the flow rate of drift gas was 1200 mL/min. Under the optimized conditions, the dominant reactant ions was O-2(H2O)n and could be used to directly detect the common explosives, such as trinitrotoluene (TNT), ammonium nitrate (AN), nitroglycerin (NG), pentaerythritol tetranitrate (PETN) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). The limit of detection of TNT was 200 pg/μL. These results indicated that negative corona discharge ionization source, with the advantanges of the high sensibility, simple structure and no radioactivity, could be used as a potential and promising ionization source for ion mobility spectrometry to detect explosives.