Test method for vapor collection and ion mobility detection of
explosives with low vapor pressure
Abstract
Rationale: IMS has been widely used for the on-site detection of
explosives. Air sampling method is applicable only when the
concentration of explosive vapor is considerably high in the air, but
vapor pressures of common explosives such as TNT, RDX, and PETN are very
low. A test method for analyzing the vapor detection efficiency of
explosives with low vapor pressure via IMS was developed using
artificial vapor and collection matrices. Methods: Artificial explosive
vapor was produced by spraying an explosive solution in acetone. Fifteen
collection matrices of various materials with woven or nonwoven
structure were tested. Two arrangements of horizontal and vertical
positions of the collection matrices were employed. Explosive vapor
collected in the matrix was analyzed through IMS. Results: Only three
collection matrices of stainless steel mesh (SSM),
polytetrafluoroethylene sheet (PFS), and lens cleansing paper (LCP)
showed the TNT and/or RDX ion peaks at explosive vapor concentration of
49 ng/L. There was no collection matrix to detect PETN vapor at lower
than 49 ng/L. For the PFS, TNT and RDX were detected at 49 ng/L vapor
concentration. For the LCP, TNT and RDX were detected at vapor
concentrations of 14 and 49 ng/L, irrespectively. Conclusions: The
difference in the explosive vapor detection efficiencies could be
explained by the adsorption and desorption capabilities of the
collection matrices. The proposed method can be used for evaluating the
vapor detection efficiency of hazardous materials with low vapor
pressure.