Abstract: A chemical sensor for detecting a chemical species in a gas comprises a detector element including a porous organic semiconductor comprised of a material on which the chemical species in the gas is adsorbed. The chemical sensor further comprises a power source for producing a bias voltage and a depletion region in the detector element. The chemical species percolates through the organic semiconductor and into the depletion region under the bias voltage, causing a change in the capacitance of the detector element. A light source irradiates the gas with light before entering the detector element. The light changes the chemical properties of the chemical species and enhances the adsorption selectivity of the organic semiconductor. The chemical sensor can determine both the presence and concentration of the chemical species in the gas based on the change in capacitance in the detector element. The chemical sensor can be provided in a portable unit suitable for field testing applications.

Abstract: The invention features an analysing device (1) comprising a body (2) in which are arranged or provided: an intake aperture (3) for a starting liquid sample, a liquid flow circuit (5) comprising at least one operating cell (6) for a processed liquid sample, obtained from all or part of the original sample, communicating with the said intake aperture (3), the said flow circuit defining, in at least two dimensions of the card, one determined geometric line, such that any alteration in the card orientation in a three-dimensional reference frame, causes the liquid to flow under gravity only, from one part of the said circuit to another,for instance from one side or another of the operating cell, (6) characterised in that, the flow circuit (5) is continuous, and looped on itself between the said aperture (3) and the said operating cell (6).

Abstract: An ultratrace detector system for hand-held gas chromatography having high sensitivity, for example, to emissions generated during production of weapons, biological compounds, drugs, etc. The detector system is insensitive to water, air, helium, argon, oxygen, and C0.sub.2. The detector system is basically composed of a hand-held capillary gas chromatography (GC), an insulated heated redox-chamber, a detection chamber, and a vapor trap. For example, the detector system may use gas phase redox reactions and spectral absorption of mercury vapor. The gas chromatograph initially separates compounds that percolate through a bed of heated mercuric oxide (HgO) in a silica--or other metal--aerogel material which acts as an insulator.

Abstract: A method for placing fluorescent single molecules on a surface of a substrate includes dropping a sample solution in which fluorescent molecules are dissolved in a predetermined concentration in a volatile, organic solvent, onto a slip of paper placed on the substrate and pulling the slip of paper so as to make the dropped sample solution traverse the surface of the substrate before the organic solvent evaporates. Since a single molecular layer of fluorescent molecules with high uniformity can be placed readily on the surface of the substrate, measurement of fluorescence and measurement of scattered light can be carried out accurately and structural defects of the surface of substrate can be visualized from luminous spots of fluorescence and from luminous spots of scattered light.

Abstract: A flow injection analytical apparatus which is capable of continuously performing flow analysis of a sample, produces precipitates during the flow through a capillary. The precipitation separation type continuous flow analytical apparatus has a sample injection portion, a reagent addition portion and an analytical portion which are integrally communicated by a measurement pipeline to form a measurement system. A precipitant addition portion and a filtration portion are provided between the sample injection portion and the reagent addition portion in order to continuously perform production and filtration of precipitates during flow of the sample solution to the reagent addition portion.

Abstract: A selective catalytic material is used to catalyze selective oxidation of unsaturated hydrocarbons, e.g., olefins, in the presence of carbon monoxide. The catalytic material comprises phosphated ceria containing from 0.1 to 20, preferably from 1 to 5, percent by weight phosphate component (calculated as elemental phosphorus). The phosphated ceria may be made by mixing particles of ceria and a solution containing phosphates to disperse the desired amount of phosphate component on the ceria and calcining the particles after separation of them from the solution. The resulting selective catalytic material is contacted under oxidizing conditions with a gas stream containing an oxidant, e.g., air, carbon monoxide and one or more unsaturated hydrocarbons.

Abstract: The present invention provides a method for preparing a VOC sample for carbon and chlorine isotope ratio analysis by mass spectrometer. A VOC sample is placed in a combustion tube and reacted with CuO to form CO.sub.2 and CuCl. The CO.sub.2 is then extracted and analyzed for the carbon isotope ratio. The CuCl is separated from the excess CuO and reacted with CH.sub.3 I to form CH.sub.3 Cl, extracted and analyzed for chlorine isotope ratio.

Abstract: A halogen gas detector comprises a coil comprising an oxidation-resistant metal wire with a nonreactive oxide coating wound into a double helix defining a cylindrical space, a conductive metal pin positioned within the cylindrical space making no contact with the coil, finely divided sintered in place sodium titanate filling the space between the coil and the pin.

Abstract: In a method for infrared-optical determination of the concentration of at least one chemical analyte in a liquid sample, where the liquid sample is passed through a measuring cell and irradiated with infrared radiation of a single narrow waverange and infrared absorption is measured, the analyte being determined is subject to a chemical reaction before measurement, which should leave the other components of the liquid sample unaffected, and the change in infrared absorption caused by the chemical reaction with the analyte is measured as a unique function of the analyte concentration to be determined.