Detection of Military Explosives by Atmospheric Pressure Chemical Ionization Mass Spectrometry with Counter-Flow Introduction

Abstract

To detect vapors from explosives, we have developed a new detection system based on a novel ion source for atmospheric pressure chemical ionization (APCI). The direction of the sample gas flow introduced into the ion source is opposite to that of the ion flow produced by the ion source. We call this technique “counter‐flow introduction” (CFI). The CFI ion source has high ionization efficiency for nitro‐compounds and is installed in an ion‐trap mass spectrometer. Our tests on various military explosives show that this system is suitable for practical on‐line explosive detection; namely major explosives can be detected within a few seconds without any pretreatment of the sample gases.

Atmospheric pressure chemical ionization of explosives using alternating current corona discharge ion source

“…In order to check the suggestion, DFT calculations were carried out. Figure 6 shows the path of reaction (1). First, the NO 3 À ion is bound strongly (ΔE = À21.4 kcal/mol) to two carbon atoms of the benzene ring of TNT.…”

“…For the continuous gas introduction, Takada et al developed the counter-flow atmospheric pressure chemical ionization (APCI) for the detection of explosives. [1,2] They used 0.2-0.3 mm inner diameter (i.d.) capillaries for the gas sampling and detected explosives with high sensitivities.…”

High‐throughput walkthrough detection portal for counter terrorism: detection of triacetone triperoxide (TATP) vapor by atmospheric‐pressure chemical ionization ion trap mass spectrometry

“…Atmospheric‐pressure chemical ionization (APCI) is a well‐known technique for ionizing explosive molecules . To improve its sensitivity and robustness, we have previously developed the counter‐flow‐introduction (CFI) mode . Figure shows a schematic diagram of an APCI ion source operating in CFI mode.…”

“…We have already developed explosives trace detectors (ETDs) based on mass spectrometry . A typical operating procedure of an ETD is as follows.…”

“…We have already developed explosives trace detectors (ETDs) based on mass spectrometry. [2,3] A typical operating procedure of an ETD is as follows. Trace contaminants of explosives attached onto objects to be checked are wiped by a sheet, which is introduced into a heating unit to vaporize the explosive molecules.…”