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 detection system for detecting the presence of predetermined compounds in a sample. The system comprises a sample injection means, a chromatographic column, a conversion means and one or more specific gas detectors. The conversion means transforms the column effluent to combustion products in the gas phase, after which those combustion products are transferred to the specific gas detectors. In one embodiment for detecting nitrogen compounds, the conversion means includes an oxygen-rich flame, a means to control the flame to have a temperature in the range 600.degree.-1700.degree. C., means to inject the column effluent into the flame, and an input port for transferring the flame effluent to a specific nitrogen detector.

Abstract: A detection system for detecting the presence of predetermined compounds in a sample. The system comprises a sample injection means, a chromatographic column, a conversion means and one or more specific gas detectors. The conversion means transforms the column effluent to combustion products in the gas phase, after which those combustion products are transferred to the specific gas detectors. In one embodiment for detecting nitrogen compounds, the conversion means includes an oxygen-rich flame, a means to control the flame to have a temperature in the range 600.degree.-1700.degree. C., means to inject the column effluent into the flame, and an output port for transferring the flame effluent to a specific nitrogen detector.

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 chromatographic system is provided for detecting in a liquid sample the presence of organic nitrogen containing compounds. A liquid chromatograph separates constituents of the liquid sample and discharges the separated constituents in a timewise distribution. Effluent from the chromatograph is atomized into a converter and there oxidized at a temperature approximately in the range 600.degree. to 800.degree. C for converting the nitrogen in the organic nitrogen containing compound to nitric oxide. Sufficient oxygen is supplied to the converter to fully oxidize the sample introduced therein. Effluent is transferred from the converter to a nitric oxide detector which measures the nitric oxide present in the converted sample and thereby provides a measurement of the organic nitrogen containing compound in the sample.

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: The N-nitroso compound content of a sample is measured by selectively breaking the N-NO bond in the N-nitroso compound molecule by non-catalytic pyrolyzation at temperatures in the range 300.degree. C to 500.degree. C, thereby liberating nitric oxide (NO), and by the subsequent measurement of the amount of nitric oxide liberated. The apparatus comprises a chromatograph and an NO detector together with a non-catalytic pyrolyzer. The pyrolyzer includes a chemically inert material configured to provide a cylindrical cross-section flow path for the chromatograph effluent. The pyrolyzer further includes the temperature control means for adding thermal energy at a controlled rate so that the flow path is characterized by temperatures in the range of 300.degree. C to 500.degree. C.

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 pressure therein, whereby gaseous effluent from the trap substantially consists of the specific gas and an inert 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.

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: The N-nitrosoamine content of a sample is measured by breaking the N--NO bond in the N-nitrosoamine molecule so as to liberate nitric oxide and thereafter measuring the amount of nitric oxide liberated.