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The detection of explosive substances (ESs) concealed in different objects, in particular luggage or carry-on bags, is an urgent problem in the set of counter-terror measures. One of known approaches [...], A procedure is proposed for the determination of the vapor concentration of 2,4,6-trinitrotoluene (TNT) in air at a level of [10.sup.-16] g/[cm.sup.3] in the control of objects for the presence of TNT. The procedure includes preconcentration of TNT vapors and gas chromatographic determination with a limit of TNT detection at a level of 0.08 [+ or -] 0.02 pg in a sample. The procedure was applied to the control objects in cells of typical automatic luggage locker with sampling through sampling air ducts. A measure of sample losses as the breakthrough of vapors through sampling air ducts and gas dynamic conditions for the reduction of vapor losses as the ratio of diffusion coefficient to the air duct flow rate were proposed. The time constant of the saturation of the sampling system with TNT vapors and the time constant of its cleaning were determined. It was shown that TNT vapors can be detected virtually satisfactorily near TNT-containing objects with sampling through long channels. Keywords: gas chromatography, substance sampling at trace concentrations, high-sensitivity detection of explosives DOI:10.1134/S1061934817110041

Polycapillary gas chromatographs (GC) EKHOA-PID with a photoionization detector and air as a carrier gas are used for the determination of trace concentrations of hydrocarbons at a level of [10.sup.-10] [...], The results of determination of Henry's coefficients for an equilibrium vapor containing trace concentrations of acetone, benzene, toluene, and xylenes over their aqueous solutions are presented. Continuous gas extraction is used. Keywords: Henry's coefficient, trace concentration, gas chromatography, photoionization detector DOI: 10.1134/S1061934817100112

INTRODUCTION According to the Convention On the Marking of Plastic Explosives for the Purposes of Detection of the International Civil Aviation Organization, signed in 1991, nitrocompounds 4-nitrotoluene (NT) and 2,3-dimethyl-2,3-dinitrobutane [...], Results of the study of the conditions of detection of traces of marking agents added to industrial plastic explosives in air using preconcentration and subsequent analysis on a ECHO-V-IDVS modernized gas chromatograph with a polycapillary column, an ionization detector of a varying selectivity (IDVS), and atmospheric air as a carrier gas are presented. A significant effect of air humidity on the limits of detection for 4-nitrotoluene and 2,3-dimethyl-2,3-dinitrobutane is demonstrated; the highest IDVS sensitivity was observed at the humidity of the carrier gas less than 8.5 mg/[m.sup.3]. For the preconcentration of marking agents, concentrators based on Tenax adsorbent or those produced as metal wire grids coated with a stationary phase are most efficient. The limits of detection for vapors of marking agents in sampling 1 L of air to a concentrator are 22 pg/[cm.sup.3] for 4-nitrotoluene and 0.1 pg/[cm.sup.3] for 2,3-dimethyl-2,3-dinitrobutane. Keywords: marking agents, 4-nitrotoluene, 2,3-dimethyl-2,3-dinitrobutane, ionization detector of a varying selectivity, polycapillary column, preconcentration DOI: 10.1134/S1061934814120053

The solution of a number of safety problems depends on the availability of timely information on the source of contamination, substances, and contamination level. This requires rapid instruments of infield [...], A three-step scheme for a miniature air purification filter for a gas chromatograph has been proposed. A method for controlling the selectivity of a new ion gas chromatography detector has been considered using a simulating model. The possibility of determining explosive traces by a gas chromatograph with air as a carrier gas has been demonstrated. Keywords: gas chromatography, air carrier gas, air purification, ion filter, detection, explosives DOI: 10.1134/S1061934813110026

In solving the topical task of the determination of explosives, an important role is played by the methods of analytical chemistry, i.e., the identification of organic materials in trace amounts [...], The progress in analytical methods for the determination of explosive done by Russian scientists is reviewed: gas analytical; nuclear physical, including neutron activation analysis; nuclear quadruple resonance (NQR); and optical spectroscopy. Keywords: identification, explosives, gas analysis, elemental analysis, optical spectroscopy. DOI: 10.1134/S1061934811110074