Enhanced selectivity of electron capture detector for nitroaromatic explosives through the application of electron attachment reactions

Abstract

Differences between the electron attachment reactions of thermal electrons and representive classes of organic molecules with high electron affinities were used to selectively identify nitroaromatics. The investigations showed that the reactions of thermal electrons with nitroaromatics lead to the formation of products with very low electron affinities. By contrast, other analytes with high electron affinities such as polyhalogenated organics, lead to products with high electron affinities. This difference was exploited to differentiate between nitroaromatics and polychlorinated organics with a monitoring device consisting of a tandem arrangement of two electron capture detectors connected in series with an electron capture detectors connected in series with an electron attachment reactor. The tandem ECD arrangement was used for selective determination of nitroaromatics vapors in the presence of interfering compounds at ppb and sub ppb concentrations.