单向气流负电晕放电离子迁移谱的研究及其在爆炸物检测中的应用

基于离子迁移谱的爆炸物探测仪多采用放射性电离源,发展非放射性电离源一直是该技术的研究热点。本研究基于电晕放电原理设计了一种新型负电晕放电电离源结构,结合自行研制的离子迁移谱仪,应用于痕量爆炸物的快速、高灵敏检测。单向气流模式下,对此电离源的气流、放电电压等运行参数进行了系统优化,得到最佳实验条件为：电晕放电电离源结构的电极环孔直径为3 mm,针-环距离为2 mm,放电电压为2400 V,漂气流速为1200 mL/min。在此条件下,避免了放电副产物氮氧化物和臭氧等引发的一系列复杂反应,得到了单一的反应试剂离子O-2(H2O)n。将其应用于爆炸物,如2,4,6-三硝基甲苯(TNT)、硝酸铵(AN)、硝化甘油( NG)、太安( PETN)、黑索金( RDX)等的高灵敏快速直接检测,对TNT的检测限达到200 pg/μL。结果表明,此负电晕放电电离源具有灵敏度高、结构简单、无辐射性、反应试剂离子单一等优点,在爆炸物快速高灵敏检测、公共安全保障等方面具有广阔的应用前景。

Development of Unidirectional Negative Corona Discharge Ion Mobility Spectrometer for Detection of Explosives

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.