脉冲式掺杂剂加入技术提高离子迁移谱仪器的灵敏度及其机理分析

A novel pulsed doping method for enhancing the sensitivity of ion mobility spectrometry and its mechanism

研究了一种通过脉冲方式加入六氯乙烷(C2Cl6)掺杂剂来提高离子迁移谱仪器检测爆炸物灵敏度的方法。持续加入掺杂剂的传统方法可以提高仪器对黑索金(RDX)和奥克托今(HMX)的检测灵敏度。然而,此方法会降低梯恩梯(TNT)和2,4-地恩梯(DNT)的检测灵敏度,同时会使黑火药(BP)无法检测。由于沸点相对较高,RDX和HMX的气化速度相对较低,因此它们的离子迁移特征峰出峰时间要晚于TNT,2,4-DNT和BP。基于此差异,在仪器完成对TNT,2,4-DNT和BP足够特征分析谱线的采集后,C2Cl6以一种脉冲的方式加入到离化区中用于提高RDX和HMX的检测灵敏度。通过优化加入时机和加入量,在不影响TNT,2,4-DNT和BP检测灵敏度的情况下,该方法可以将RDX和HMX的检测灵敏度提高100倍以上。

In this paper, a novel pulsed doping method was developed to enhance the sensitivity of ion mobility spectrometry （IMS） for detecting explosives using hexachloroethane （C2C16） as the dopant. The sensitivity for detection of some explosives such as hexogen （RDX） and cyclotetramethylene tetranitramine（HMX）were enhanced by adding dopants constantly to the ionization region of IMS with the conventional doping method. However, the detection for black powder（BP）was hindered and the sensitivity for determination of 2,4,6 -Trinitrotoluene （TNT） and 2,4-Dinitrotoluene （DNT） was depressed. The characteristic peaks of RDX and HMX appeared much later than those of TNT, DNT and BP due to their lower gasification speed, which was caused by their relatively lower saturation vapor pressure. Based on the difference, the dopant of C2C16 was added into the ionization region in a pulsed mode to enhance the sensitivity of RDX and HMX after the acquisition of enough information by the IMS instrument for the accurate detection of TNT, DNT and BP. By optimizing the addition time and amount of the dopant, this method can enhance the sensitivity for RDX and HMX by over 100 times without affecting the detection of TNT, DNT and BP.