Abstract: A highly selective, sensitive, fast detection system and method are disclosed for detecting vapors of specific compounds in air. Vapors emanating from compounds such as explosives, or stripped from surfaces using heat and suction from a hand-held sample gun, are collected on surfaces coated with gas chromatograph (GC) material which trap explosives vapors but repel nitric oxide, then are desorbed and concentrated in one or more cold spot concentrators. A high speed gas chromatograph (GC) separates the vapors, after which specific vapors are decomposed in two pyrolyzers arranged in parallel and the resulting nitric oxide is detected. A low temperature pyrolyzer with silver produces NO from nitramines or nitrite esters; a high temperature pyrolyzer decomposes all explosives vapors to permit detection of the remaining explosives. Also disclosed is a series arrangement of pyrolyzers and gas chromatographs and an NO detector to time-shift detection of certain vapors and facilitate very fast GC analyses.

Abstract: A highly selective, sensitive, fast detection system and method are disclosed for detecting vapors of specific compounds in air. Vapors emanating from compounds such as explosives, or stripped from surfaces using heat and suction from a hand-held sample gun, are collected on surfaces coated with gas chromatograph (GC) material which trap explosives vapors but repel nitric oxide, then are desorbed and concentrated in one or more cold spot concentrators. A high speed gas chromatograph (GC) separates the vapors, after which specific vapors are decomposed in two pyrolyzers arranged in parallel and the resulting nitric oxide is detected. A low temperature pyrolyzer with silver produces NO from nitramines or nitrite esters; a high temperature pyrolyzer decomposes all explosives vapors to permit detection of the remaining explosives. Also disclosed is a series arrangement of pyrolyzers and gas chromatographs and an NO detector to time-shift detection of certain vapors and facilitate very fast GC analyses.

Abstract: A highly selective, sensitive, fast detection system and method are disclosed for detecting vapors of specific compounds in air. Vapors emanating from compounds such as explosives, or stripped from surfaces using heat and suction from a hand-held sample gun, are collected on surfaces coated with gas chromatograph (GC) material which trap explosives vapors but repel nitric oxide, then are desorbed and concentrated in one or more cold spot concentrators. A high speed gas chromatograph (GC) separates the vapors, after which specific vapors are decomposed in two pyrolyzers arranged in parallel and the resulting nitric oxide is detected. A low temperature pyrolyzer with silver produces NO from nitramines or nitrite esters; a high temperature pyrolyzer decomposes all explosives vapors to permit detection of the remaining explosives. Also disclosed is a series arrangement of pyrolyzers and gas chromatographs and an NO detector to time-shift detection of certain vapors and facilitate very fast GC analyses.

Abstract: A highly selective, sensitive, fast detection system and method are disclosed for detecting vapors of specific compounds in air. Vapors emanating from compounds such as explosives, or stripped from surfaces using heat and suction from a hand-held sample gun, are collected on surfaces coated with gas chromatograph (GC) material which trap explosives vapors but repel nitric oxide, then are desorbed and concentrated in one or more cold spot concentrators. A high speed gas chromatograph (GC) separates the vapors, after which specific vapors are decomposed in two pyrolyzers arranged in parallel and the resulting nitric oxide is detected. A low temperature pyrolyzer with silver produces NO from nitramines or nitrite esters; a high temperature pyrolyzer decomposes all explosives vapors to permit detection of the remaining explosives. Also disclosed is a series arrangement of pyrolyzers and gas chromatographs and an NO detector to time-shift detection of certain vapors and facilitate very fast GC analyses.

Abstract: A highly selective, sensitive, fast detection system and method are disclosed for detecting vapors of specific compounds in air. Vapors emanating from compounds such as explosives, or stripped from surfaces using heat and suction from a hand-held sample gun, are collected on surfaces coated with gas chromatograph (GC) material which trap explosives vapors but repel nitric oxide, then are desorbed and concentrated in one or more cold spot concentrators. A high speed gas chromatograph (GC) separates the vapors, after which specific vapors are decomposed in two pyrolyzers arranged in parallel and the resulting nitric oxide is detected. A low temperature pyrolyzer with silver produces NO from nitramines or nitrite esters; a high temperature pyrolyzer decomposes all explosives vapors to permit detetion of the remaining explosives. Also disclosed is a series arrangement of pyrolyzers and gas chromatographs and an NO detector to time-shift detection of certain vapors and facilitate very fast GC analyses.

Abstract: A highly selective, sensitive, fast detection system and method are disclosed for detecting vapors of specific compounds in air. Vapors emanating from compounds such as explosives, or stripped from surfaces using heat and suction from a hand-held sample gun, are collected on surfaces coated with gas chromatograph (GC) material which trap explosives vapors but repel nitric oxide, then are desorbed and concentrated in one or more cold spot concentrators. A high speed gas chromatrograph (GC) separates the vapors, after which specific vapors are decomposed in two pyrolyzers arranged in parallel and the resulting nitric oxide is detected. A low temperature pyrolyzer with silver produces NO from nitramines or nitrite esters; a high temperature pyrolyzer decomposes all explosives vapors to permit detection of the remaining explosives. Also disclosed is a series arrangement of pyrolyzers and gas chromatographs and an NO detector to time-shift detection of certain vapors and facilitate very fast GC analyses.

Abstract: Disclosed is a method and apparatus for detecting hydrazine, monomethylhydrazine (MMH), and unsymmetrical dimethylhydrazine (UDMH) in a gaseous sample. The hydrazine compound detector includes a sample converter wherein vapors of an aldehyde such as acetaldehyde or a ketone such as acetone are mixed with a sample in gaseous form, and the mixture is allowed to react to form azine and hydrazone derivatives of the aldehyde or ketone. The derivatives may be transported long distances and then analyzed, as by heating in the presence of an oxidant in a pyrolyzer containing a nickel surface to produce nitric oxide (NO), followed by measurement of the NO in a NO detector such as a chemiluminescent analyzer.

Abstract: A method and apparatus are disclosed for extracting amine compounds from air samples without loss due to formation of nitrosamine artifacts. The apparatus includes a cartridge having a separation zone between a first port and a second port. The separation zone contains an air pervious packing of a granular, solid phase amine complexing agent. The method includes a first step of driving an air sample through the separation zone of the cartridge from the first port to the second port, and a second step of driving an eluent through the separation zone from the second port to the first port, or backflushing the cartridge. To extract amine compounds, the eluent is a solvent for the amine complexing agent in the separation zone of the cartridge. The method may contain the further step of determining the amine compound concentration of at least a portion of the eluate which passes from the separation zone following the second step of the method.

Abstract: A molecular sieve trap is disclosed for selective trapping of substances in a gas stream, the trap being particularly useful in systems for detecting nitrogen compounds such as N-nitrosamines or nitrogen oxides in a sample. The trap comprises a cartridge containing a packing of a granular adsorbent molecular sieve material with a carefully controlled pore size of about ten angstroms and a preference for adsorbing polar substances. The packing readily passes NO and NO.sub.2 gases in a gas stream directed through the trap while trapping and retaining larger and/or more polar molecules such as those of double-bonded carbon compounds and sulfur compounds which could otherwise interfere with subsequent measurement of the NO or NO.sub.x content of the gas stream. An N-nitroso compound detection system incorporating the molecular sieve trap is described wherein the molecular sieve trap is interposed between a pyrolyzer and a chemiluminescent NO detector to selectively trap substances in the reactor effluent.

Abstract: An air-sampling cartridge is disclosed for collecting organic compounds such as N-nitrosamines from air for analysis. The cartridge is formed by joining two injection-molded plastic parts: a generally cylindrical cartridge body into which air-pervious packings of granular adsorbent materials may be loaded, and a cartridge cap which is ultrasonically welded to the body to partially close one end of the cartridge. The cap and body define a cartridge with an inlet and outlet shaped to facilitate connection of the cartridge to a pump used to draw air samples through the cartridge, to allow connection of two or more cartridges in series, and to accommodate standard-sized syringes used in removing trapped compounds from the cartridge for analysis.The cartridge also includes a retention clip integrally molded with the cartridge body and cap for permitting the cartridge to be attached to the clothing of a person during air-sampling.

Abstract: A method and apparatus are disclosed for extracting N-nitroso compounds from air samples without artifact formation of nitrosamines from precursors in the sample. The apparatus includes a cartridge having two zones between a first port and a second port. The first zone, closest to the first port, contains an air pervious packing of a granular, solid phase amine complexing agent. The second zone, closest to the second port, contains an air pervious packing of a mixture of a granular, solid phase amine complexing agent and a particulate sorbent adapted to extract and concentrate N-nitroso compounds from air. The method includes a first step of driving an air sample through the first and second contiguous zones of the cartridge in succession, and a second step of driving an eluent through the second and first zones in succession, or backflushing the cartridge.

Abstract: Methods and apparatus for removing compounds from air to clean the air and for providing quantitative analysis of the content of particular organic compounds in the air. Apparatus is described having a separation zone packed with a magnesium silicate or calcium silicate material in the form of finely divided particles which are effective in trapping and holding substantially all of certain predetermined compounds present in air passed through the material. The silicate-packed separation zone may be employed as a highly efficient filter to purify air containing pollutants or contaminants. Also described are a method and apparatus for accurately determining the content of predetermined organic compounds in a sample of air using a collection tube containing a sorbent material such as dry, finely divided activated magnesium trisilicate.

Abstract: A method by which in vivo N-nitroso compounds are detected. The N-nitroso compounds appear in the metabolic system or are formed therein from one or more precursors. The metabolic reactions are terminated instantly at a predetermined point in time, as by freezing in a liquidied gas, and the frozen sample is analyzed for the presence of N-nitroso compounds.

Abstract: A liquid-gas interface is provided between a heated reaction chamber of an N-nitroso compound detection system and a liquid chromatograph. The liquid-gas interface atomizes liquid chromatograph effluent, including the N-nitroso compounds to be measured, with a stream of carrier gas, into the reaction chamber. In the heated reaction chamber, the effluent from the interface is vaporized. Condensation of non-volatile N-nitroso compounds is avoided by preheating the liquid effluent prior to atomization.

Abstract: Apparatus for detecting the amount of a specific compound in a sample dissolved in a liquid solvent. The apparatus comprises, in combination, a high pressure liquid chromatograph, means to transform the chromatograph effluent to the gaseous state, a cold trap and a specific gas detector. The cold trap includes means to cool the gas injected therein at a predetermined temperature, and means to maintain a predetermined pressure therein, whereby the solvent is condensed and the gaseous effluent from the trap substantially consists of the specific gas.

Abstract: Apparatus for detecting the amount of a specific compound in a sample. The apparatus comprises, in combination, a gas chromatograph, a cold trap and a specific gas detector. The cold trap includes means to cool the gas passing therethrough to a predetermined temperature, and means to maintain a predetermined pressure therein, whereby the chromatograph carrier gas is condensed and the gaseous effluent from the trap substantially consists of the specific gas.

Abstract: Apparatus for detecting the amount of a specific compound in a sample dissolved in a liquid solvent. The apparatus comprises, in combination, a high pressure liquid chromatograph, means to transform the chromatograph effluent to the gaseous state, a cold trap and a specific gas detector. The cold trap includes means to cool the gas injected therein at a predetermined temperature, and means to maintain a predetermined pressure therein, whereby the solvent is condensed and the gaseous effluent from the trap substantially consists of the specific gas.