title: Detection of nitro-based and peroxide-based explosives by fast polarity-switchable ion mobility spectrometer with ion focusing in vicinity of Faraday detector.
abstract: Ion mobility spectrometer (IMS) has been widely deployed for on-site detection of explosives. The common nitro-based explosives are usually detected by negative IMS while the emerging peroxide-based explosives are better detected by positive IMS. In this study, a fast polarity-switchable IMS was constructed to detect these two explosive species in a single measurement. As the large traditional Faraday detector would cause a trailing reactant ion peak (RIP), a Faraday detector with ion focusing in vicinity was developed by reducing the detector radius to 3.3 mm and increasing the voltage difference between aperture grid and its front guard ring to 591 V, which could remove trailing peaks from RIP without loss of signal intensity. This fast polarity-switchable IMS with ion focusing in vicinity of Faraday detector was employed to detect a mixture of 10 ng 2,4,6-trinitrotoluene (TNT) and 50 ng hexamethylene triperoxide diamine (HMTD) by polarity-switching, and the result suggested that [TNT-H](-) and [HMTD+H](+) could be detected in a single measurement. Furthermore, the removal of trailing peaks from RIP by the Faraday detector with ion focusing in vicinity also promised the accurate identification of KClO4, KNO3 and S in common inorganic explosives, whose product ion peaks were fairly adjacent to RIP.
authors.affiliation: 1] Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning, 116023, People's Republic of China [2] University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China.
authors.forename: Qinghua
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: 1] Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning, 116023, People's Republic of China [2] University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China.
authors.forename: Liying
authors.initials: L
authors.lastname: Peng
authors.affiliation: 1] Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning, 116023, People's Republic of China [2] University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China.
authors.forename: Dandan
authors.initials: D
authors.lastname: Jiang
authors.affiliation: Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning, 116023, People's Republic of China.
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.affiliation: Jiangsu Province Institute of Quality and Safety Engineering, Nanjing, Jiangsu, 210046, People's Republic of China.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Wang
authors.affiliation: Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning, 116023, People's Republic of China.
authors.forename: Haiyang
authors.initials: H
authors.lastname: Li