Novel Trace Chemical Detection Technologies for Homeland Security

Trace chemical detection issues relevant to Homeland Security (HS), specifically to the detection of chemical warfare agents (CWAs), biological species, and high explosives are discussed. A special attention is paid to the ion mobility spectrometry, its improved version, field compensated ion mobility spectrometry (known also as FIS, FAIMS, microDMx™, and DMS), and mass spectrometry. Sampling and analysis scenarios are discussed with special emphasis on the ways to prevent positive and negative false alarms, like through 'doping', for example. Possible explanations of false negatives and ways of their prevention as well as the detection of well hidden explosives are discussed. Reasons for the X-ray screening being the primary and the trace chemical detection-the secondary screening methodology at airports are explained. Sampling; pyrolysis/ volatilization of sample; transfer of volatilized sample, and its ionization; transfer of ions, their separation, and detection are discussed, and the ways of improvement proposed. Advantages and disadvantages of multipeak detection are presented. A comeback of mass spectrometry is observed with instruments being miniaturized and equipped with innovative ionization sources which should make sampling easier and detection more specific. Importance of the miniaturization of the transportation security instrumentation is stressed. A confirmational analysis is suggested as another important tool in the prevention of false negatives and positives, especially when the multipeak detection is not possible. A new detection system, consisting of the miniaturized FAIMS and mass spectrometer is proposed as the sensitive, specific, portable and rapid response trace chemical detection system for Homeland Security applications.