title: Real-time explosive particle detection using a cyclone particle concentrator.
abstract: BACKGROUND
  There is a need for more rapid methods for the detection of explosive particles. We have developed a novel real-time analysis technique for explosive particles that uses a cyclone particle concentrator. This technique can analyze sample surfaces for the presence of particles from explosives such as TNT and RDX within 3 s, which is much faster than is possible by conventional methods.
  
  
  METHODS
  Particles are detached from the sample surface with air jet pulses, and then introduced into a cyclone particle concentrator with a high pumping speed of about 80 L/min. A vaporizer placed at the bottom of the cyclone particle concentrator immediately converts the particles into a vapor. The vapor is then ionized in the atmospheric pressure chemical ionization (APCI) source of a linear ion trap mass spectrometer.
  
  
  RESULTS
  An online connection between the vaporizer and a mass spectrometer enables high-speed detection within a few seconds, compared with the conventional off-line heating method that takes more than 10 s to raise the temperature of a sample filter unit. Since the configuration enriched the number density of explosive particles by about 80 times compared with that without the concentrator, a sub-ng amount of TNT particles on a surface was detectable.
  
  
  CONCLUSIONS
  The detection limit of our technique is comparable with that of an explosives trace detector using ion mobility spectrometry. The technique will be beneficial for trace detection in security applications, because it detects explosive particles on the surface more speedily than conventional methods.
authors.affiliation: Hitachi Ltd, Central Research Laboratory, 1-280 Higashi-koigakubo, Kokubunji-shi, Tokyo, 185-8601, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Hashimoto
authors.forename: Hisashi
authors.initials: H
authors.lastname: Nagano
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Takada
authors.forename: Hideo
authors.initials: H
authors.lastname: Kashima
authors.forename: Masakazu
authors.initials: M
authors.lastname: Sugaya
authors.forename: Koichi
authors.initials: K
authors.lastname: Terada
authors.forename: Minoru
authors.initials: M
authors.lastname: Sakairi