Abstract: A method for producing a nanocrystalline, gas-sensitive layer structure. The method for producing a nanocrystalline, gas-sensitive layer structure on a substrate comprises the steps: depositing a base layer made of a base material; depositing a doping layer made of a doping material; repeating the preceding steps; and performing a tempering step, whereby a gas-sensitive, nanocrystalline layer structure is produced.

Abstract: An apparatus for extracting a material from a liquid includes a concentration stage having a filter, a first path from the filter, and a second path from the filter. Under this configuration, the concentration stage accepts an initial liquid volume. A first liquid not having material collected by the filter is passed along the first path, and concentrated liquid having material therein, which is entrapped by the filter, is directed to the second path. The apparatus also includes an aerosolizing stage coupled to the concentration stage that converts the concentrated liquid into an aerosol and a drying stage that dries the aerosol such that material extracted from the aerosol onto a material substrate.

Abstract: The system for detecting volatile organic compounds (VOCs) of this present invention comprises a detecting material made by blending a nano-material and a conductive polymer. The system for detecting VOCs presents the property of high sensitivity, high sensing accuracy, quick response, and real-time VOC detecting, and is demonstrated in the present work for commercialization usage. The system for detecting VOCs can be easily operated to detect VOC without electronic detecting method, and hence this invention can reduce a lot of operation energy and procedure. Furthermore, when adding inorganic nanoparticles, the area of VOC exposure of this invention is increased and the molecular morphology variation of the detecting material is enhanced, and hence the detecting activity of the system for detecting VOCs is improved.

Abstract: An atmospheric pressure chemical ionization detector includes a reaction chamber that is configured to receive gas phase analytes. An electrode is disposed within the reaction chamber and is configured to ionize the gas phase analytes via corona discharge. A collector is disposed adjacent an outlet of the reaction chamber and is configured to attract ions from the chamber such that the ions hit the collector to induce a measurable current. The detector is configured for non-mass spectrometric detection of gas phase analyte ions.

Abstract: A gas sensor cell using a liquid crystal composite material is provided. The gas sensor cell has recovery capability and can be reused. Upon gas adsorption, the liquid crystal composite material has visually detectable color changes and changes in electrical properties to facilitate the measurement of gas concentration from low to high.

Abstract: IMS apparatus has an inlet with a preconcentrator opening into a reaction region where analyte molecules are ionized and passed via a shutter to a drift region for collection and analysis. A pump and filter arrangement supplies a flushing flow of clean gas to the housing in opposition to ion flow. A pressure pulser connects with the housing and is momentarily switched to cause a short drop in pressure, in the housing to draw in a bolus of analyte sample from the preconcentrator. Just prior to admitting a bolus of sample, the pump is turned off so that the flushing flow drops substantially to zero, thereby prolonging the time the analyte molecules spend in the reaction region.

Abstract: Chemical field effect sensors comprising nanotube field effect devices having biopolymers such as single stranded DNA or RNA functionally adsorbed to the nanotubes are provided. Also included are arrays comprising the sensors and methods of using the devices to detect volatile compounds.

Abstract: A microfabricated TID comprises a microhotplate and a thermionic source disposed on the microhotplate. The microfabricated TID can provide high sensitivity and selectivity to nitrogen- and phosphorous-containing compounds and other compounds containing electronegative function groups. The microfabricated TID can be microfabricated with semiconductor-based materials. The microfabricated TID can be combined with a microfabricated separation column and used in microanalytical system for the rapid on-site detection of pesticides, chemical warfare agents, explosives, pharmaceuticals, and other organic compounds that contain nitrogen or phosphorus.

Abstract: A device having an air sampler, an electrospray apparatus, and a fluorescence excitation and detection system. The air sampler is capable of moving air suspected of containing a biological or chemical aerosol particle into a chamber. The electrospray apparatus is capable of spraying a charged solution into the chamber to coat the aerosol particles with a coating. The solution has a fluorescent-labeled biological or chemical marker capable of specific binding to the aerosol particle. The fluorescence system is capable of detecting fluorescence of the fluorescent label in the coating. A method of detecting the aerosol particle by: moving air suspected of containing the aerosol particle into a chamber; spraying the charged solution into the chamber with an electrospray apparatus, such that a coating of the solution is formed around the particle; exciting the fluorescent label; and detecting fluorescence of the fluorescent label.

Abstract: A gas detector (25) has an electron source (1), which emits electron pulses into a reaction chamber (26) through a membrane (10). The ions formed in the reaction chamber (26) by the electron beam can be detected by means of a current detector (30) by a transfer field pulse being generated in the reaction chamber. The gas sensor (25) may have especially a miniaturized design.

Abstract: A method for ionizing and desorbing a sample for analysis includes energizing a first and second electrode to produce a glow discharge at atmospheric pressure. The method further includes supplying a carrier gas to at least a portion of the glow discharge to create effluents thereof. The method further includes conducting the effluents of the glow discharge to the sample to ionize and desorb the sample for analysis. An associated apparatus is also disclosed.

Abstract: To increase the adhesion strength of coagulated blood on a surface by increasing the surface interaction of blood-inherent components like fibrin/fibrinogen and thrombocytes it is described to treat the surface by exposing it to ionized atoms or molecules. The surface treatment according to the invention is applied on plastic disposables used in blood diagnostics (e.g. hemostasis analysis) as well as medical implants like artery sealings. The improved blood clot adhesion results in higher diagnostic security due to reduced measurement failure (e.g., for patients with increased thrombocyte content) and in better significance of special tests (e.g., hyperfibrinolysis diagnosis).

Abstract: Detecting air ingredients is obtained, a heater and gas sensitive acting layers are arranged on a substrate, which are connectable to an analyzing unit. Electrical resistances of n acting layers are connected in series; heater is a temperature sensor connected in parallel with this series connection, electrical resistance of heater is smaller than the sum of electrical resistances of acting layers and resistances are connected with a total of n+1 electrical terminals via electrodes so that heater is connected with two terminals and n?1 other terminals are connected with a respective junction that interconnects two acting layers. Heater is intermittently heated so that a predefined constant temperature of acting layers is achieved, temperature of acting layers is acquired by determining electrical resistance of heater; voltages in the series connection of acting layers are analyzed and a concentration of gases are determined from electrical resistances of acting layers.

Abstract: A chemical sample collection and detection system is disclosed. The chemical sample collection and detection system includes a sample collection device and a detection device. The sample collection device includes a housing having two opposite sides and at least one openings on each side to allow a fluid sample passing through the housing; and a sorbent material placed between the two opposite sides of the housing or a sorbent coated screen. The sorbent material adsorbs chemical vapors, and traps particles and aerosols in the fluid sample when the fluid sample passes the housing through the openings. The detection device includes an atmospheric pressure ionization source and an ion detector. The atmospheric pressure ionization source desorbs and ionizes the chemicals trapped/sorbed on the sorbent material and the ion detector analyzes the ions for the presence of the sorbed chemical.

Abstract: The present invention relates to a method of qualifying ovarian cancer status in a subject comprising: (a) measuring at least one biomarker in a sample from the subject and (b) correlating the measurement with ovarian cancer status. The invention further relates to kits for qualifying ovarian cancer status in a subject.

Abstract: The invention relates to an ion mobility spectrometer in which a measuring tube, a filter and a transport device are connected to form a circulatory gas system, with a gas inlet which introduces ambient gas for analysis into the measuring tube of the ion mobility spectrometer. The invention involves connecting the measuring tube with the ambient gas by means of a dosing channel and connecting the circulatory gas system with the ambient gas by means of an outlet channel. The outlet channel joins the circulatory gas system between the high-pressure side of the transport device and the measuring tube, so that ambient gas for analysis is introduced into the measuring tube via the dosing channel while, at the same time, gas flows out of the circulatory gas system via the outlet channel without further transport devices being required.

Abstract: A gas monitoring apparatus includes a sample introducing portion, a measurement portion, an ionization portion, a mass analysis portion, a data processing portion and a display. The sample introducing portion introduces a sample gas including an object material to be measured. The measurement portion measures a concentration of a predetermined coexisting material, which coexists with the object material in the sample gas. The ionization portion ionizes the sample gas. The mass analysis portion analyzes mass of an ion produced by the ionization portion. The data processing portion analyzes signals detected by the mass analysis portion to calculate a concentration of the object material. And the display displays results of analysis conducted by the data processing portion. The data processing portion includes an adjustment portion which adjusts the concentration of the object material according to the concentration of the predetermined coexisting material.

Abstract: An apparatus for airborne particle sorting is provided comprising a charging system adapted for applying an electrostatic charge to the particles, such that particles of at least a first group are deflected to a greater extent than particles of a second group are deflected. A focusing system is adapted for electrostatically focusing substantially at least the particles of the first group into a focused stream that is narrower than the input air stream. A deposition system is adapted for substantially depositing the particles of the first group from the focused stream upon a target surface, where the target surface may be transported to an analysis system capable of analyzing the particles deposited thereon.

Abstract: Aerosol particle analyzer (APA) for measuring an analyte in airborne particle is described. Airborne particles are first given an electrical charge and then drawn in air past an oppositely charged volume of an analysis liquid that exposed to the air at a small hole in a container, such as a capillary, that holds that analysis liquid. Electrostatic forces enhance the rate that the airborne particles collide with the small exposed volume of the analysis liquid in the hole. If the particles that collide with the analysis liquid contain the analyte, an optical property of the analysis liquid, such as the fluorescence, varies according to the amount of the analyte in the particles. This optical property is measured and the amount of analyte in the particles is determined from the measured optical property.

Abstract: An aerosol-into-liquid collector (ALC) for collecting gas-borne particles from a large volume of gas such as air into a small volume of liquid is described. The ALC uses a linear quadrupole to concentrate particles flowing in a gas and to help direct these concentrated particles toward a small volume of collection liquid so that these particles tend to combine with a small volume of collection liquid that can then be drawn from the ACL for further analysis. The particles in the gas are typically given a charge that is opposite to that of the charge imparted to the volume of collection liquid so that electrostatic forces help draw particles from the flowing gas into the small volume of liquid. The linear quadrupole focuses toward it axis particles that have the charge, mass and mobility to be stable in the linear quadrupole.

Abstract: A method is described for producing tubular substrates having parallel spaced concentric rings of electrical conductors that can be used as the drift tube of an Ion Mobility Spectrometer (IMS). The invention comprises providing electrodes on the inside of a tube that are electrically connected to the outside of the tube through conductors that extend between adjacent plies of substrate that are combined to form the tube. Tubular substrates are formed from flexible polymeric printed wiring board materials, ceramic materials and material compositions of glass and ceramic, commonly known as Low Temperature Co-Fired Ceramic (LTCC). The adjacent plies are sealed together around the electrode.

Abstract: Aerosol particle analyzer (APA) for measuring the amount of analyte in airborne particle is described. The APA uses an analysis liquid. In most embodiments, this analysis liquid is chosen so that when it is mixed with the particles, an optical property of the analysis liquid (AL) varies according to the amount of the analyte in the particles. Airborne particles are drawn into the instrument, and detected using optical methods such as light scattering or laser-induced fluorescence. When a particle of interest is detected, a charged droplet of the analysis liquid (CDAL) is ejected so that it collides with the detected particle and moves into a horizontally oriented linear quadrupole that is in an airtight container, except for small orifices to let the CDAL enter and exit.

Abstract: Aerosol particle analyzer (APA) for measuring the amount of analyte in airborne particle is described. The APA uses an analysis liquid. When this analysis liquid is mixed with the particles, an optical property of the analysis liquid (CDAL) varies according to the amount of the analyte in the particles. A charged droplet of the analysis liquid is levitated. Airborne particles are drawn into the instrument and given a charge that is opposite that of the CDAL, and made to flow near the CDAL so that electrostatic forces greatly increase the probability that the CDAL and charged particles will combine. Then the CDAL is ejected into a horizontally oriented linear quadrupole that is in an airtight container, except for a small orifice to let the CDAL enter. The CDAL is levitated in a high humidity environment so that it evaporates slowly, so that there is time for the reaction between the analyte, if any, and the CDAL can take place, and so that the optical property, typically fluorescence, can be measured.

Abstract: The instant invention involves the use of a combination of preparatory steps in conjunction with mass spectroscopy and time-of-flight detection procedures to maximize the diversity of biopolymers which are verifiable within a particular sample. The cohort of biopolymers verified within such a sample is then viewed with reference to their ability to evidence at least one particular disease state; thereby enabling a diagnostician to gain the ability to characterize either the presence or absence of at least one disease state relative to recognition of the presence and/or the absence of the biopolymer.

Abstract: An ICP analyzer has a nebulizer for nebulizing a sample fluid for the purpose of analyzing microscopic impurities within the sample fluid, a plasma torch for introducing nebulized spray into a plasma, and a spray chamber disposed between the nebulizer and the plasma torch for separating spray comprised of microscopic particles from the nebulized spray prior to introduction thereof into the plasma torch. A heating section is provided at a central portion of the spray chamber and a cooling section is provided at a peripheral section of the spray chamber, and the spray is passed between the heating section and the cooling section to improve the efficiency sample introduction into the plasma to enable highly sensitive analysis by suppressing the proportion of a solvent component that reaches the plasma torch.

Abstract: A system and method for detecting the presence of submicron sized particles in a sample taken from the environment includes a collecting a sample from the environment and purifying and concentrating the submicron particles in a sample based on the size of the particles. The purified and concentrated particles are detected with an apparatus which includes an electrospray assembly having an electrospray capillary, a differential mobility analyzer which receives the output from the capillary, and a condensation particle device for counting the number of particles that pass through the differential mobility analyzer.

Abstract: A self-adjusting, free-flowing pneumatic nebulizer interface is described for coupling fluid phase separation apparatus such as capillary electrophoresis apparatus or fluid-phase analyte delivery apparatus such as flow-injection analysis apparatus to gas phase, post-separation detection apparatus such as mass spectrometers, chemiluminescence detectors, or other similar gas phase detection apparatus. The interface combines the analytes with only the needed amount of sheath fluid to produce a combined flow whose magnitude automatically matches the self-aspiration rate of the pneumatic nebulizer interface, and which is combined with a gas flow to produce an aerosol. The resulting aerosol can then be either deposited directly on a surface, forwarded directly to a detection system or forwarded first to a conversion apparatus such as an oxidizer and the oxidized sample components are then forwarded to a detector.

Abstract: A sensor for detecting the flame occurring during a flashback condition in the fuel nozzle of a lean premix combustion system is presented. The sensor comprises an electrically isolated flashback detection electrode and a guard electrode, both of which generate electrical fields extending to the walls of the combustion chamber and to the walls of the fuel nozzle. The sensor is positioned on the fuel nozzle center body at a location proximate the entrance to the combustion chamber of the gas turbine combustion system. The sensor provides 360° detection of a flashback inside the fuel nozzle, by detecting the current conducted by the flame within a time frame that will prevent damage to the gas turbine combustion system caused by the flashback condition.

Abstract: A novel technique utilizing the precision of printed circuit board design and the physical versatility of thin, flexible substrates is disclosed to produce a new type of ion reflector. A precisely defined series of thin conductive strips (traces) are etched onto a flat, flexible circuit board substrate. Preferably, the thin conductive strips are further apart at one end of the substrate and get increasingly closer towards the other end of the substrate. The flexible substrate is then rolled into a tube to form the reflector body, with the conductive strips forming the rings of the ion reflector. The spacing between the traces, and hence the ring spacing, can be readily varied by adjusting the conductor pattern on the substrate sheet during the etching process. By adjusting the spacing between the rings, the characteristics of the field created by the reflectron can be easily customized to the needs of the user.

Abstract: A filter for reducing the cross-sensitivity of a chlorine dioxide detector to hydrogen sulfide. The filter includes a high surface area substrate impregnated with a silver (I) salt or copper (II) salt which is effective to remove hydrogen sulfide from a gas stream without producing undesirable compounds which might be detected by the sensor. The preferred compounds are copper chloride (CuCl2), copper bromide (CuBr2), silver acetate (AgO2CCH3), silver bromate (AgBrO3), silver bromide (AgBr), silver carbonate (Ag2CO3), silver chloride (AgCl), silver chromate (Ag2CrO4), silver cyanide (AgCN), silver iodate (AgIO3), silver oxide (Ag2O), silver perchlorate (AgClO4), silver permanganate (AgMnO4), silver sulfate (Ag2SO4), silver hexafluorophosphate (AgPF6), silver fluoride (AgF), silver tetrafluoroborate (AgBF4), silver iodide (AgI) and silver trifluoromethane sulfonate (AgO3SCF3).

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: Method and apparatus are disclosed for improved transfer of ionizing particles from a source chamber to a detection zone in an ionization chamber in an ionization detector. An ionization detector includes a source chamber, an inlet for introducing detector gas to the source chamber, a transitional structure including a flow guide that directs detector gas flow between the source chamber and the adjacent ionization chamber, an inlet for introducing sample gas containing an analyte into the ionization chamber, and an outlet port for exhausting the mixture of the sample gas and the detector gas. The aspect ratio of the flow guide causes the linear velocity of the detector gas stream to be highest at a throat in the flow guide and to decrease as the detector gas stream approaches a detection zone in the ionization chamber, thereby suppressing analyte diffusion from the ionization chamber through the flow guide.

Abstract: A method and sensor for distinguishing between different optical isomers (enantiomers), which sensor comprises a pair of spaced-apart contacts and a semi-conductive polymer material spanning the gap between the contacts, which polymer material includes chiral sites. The chiral sites in the polymer material are preferably formed by incorporating an optically active counterion into the polymer material, for example by growing the polymer in the presence of such a counterion, e.g. camphor sulphonic acid.

Abstract: An trace analyzer apparatus and method useful in semiconductor processing for measuring trace impurities in gases and liquids comprising a gas chromatograph serving to replace a bulk gas in a composition of bulk gas including contaminants in a bulk gas stream with a carrier gas having a higher ionization potential than that of said contaminants, where such gas chromatograph is connected to a hollow electrode (14) for initiating ionization of said contaminants by electrical discharge, where such electrode is electrically isolated from a source housing (44) and adjacent to a skimmer plate (16) that ionizes trace contaminants that are measured using a mass spectrometer, is disclosed.

Abstract: A carbon monoxide sensor including a gas detecting portion and at least a pair of electrodes, wherein the gas detecting portion includes a metal oxide represented by a following formula;Cu.sub.1-x Bi.sub.x O.sub.y(0<x<1 and 1<y<1.5).

Abstract: A flame ionization detector having a pair of spaced electrodes to which a DC voltage is applied and a flame produced between the electrodes by burning a gas whose composition is to be determined, thereby ions are produced which form an ion current between the electrodes which is representative of the gas composition to be measured. The flame detector is formed by a base plate having a first channel for inlet of the gas whose composition to be measured, a second channel for inlet of a combustion gas, a third channel connected to the first and second channels for conveying a mixture of the gases to an outlet communicating with a nozzle outlet in a ceramic plate on the base plate which faces an opening in a metal plate spaced at a predetermined distance from the ceramic plate such that the flame burns in the opening in the metal plate. An electrically conductive metal layer is disposed on the ceramic plate around the nozzle outlet therein.

Abstract: The present invention relates to a method for measuring an ion flow from a plasma to a surface in contact therewith, consisting of measuring the rate of discharge of a measuring capacitor connected between a radiofrequency voltage source and a plate-shaped probe in contact with the plasma.

Abstract: In a technique for detecting organic vapors and aerosols, e.g. of amines, hydrazines and nitrogen-containing compounds produced in combustion, molecules condense at a surface of a conductive device. By heating the conductive device in pulsed fashion, e.g. by resistance heating, condensed molecules are thermally ionized and emitted from the conductive device. Emitted ions are collected by a collector electrode, and the resulting ionic current pulse is amplified by a transimpedance circuit. The heat pulse lasts until the ionic current pulse has subsided, by which time the conductive device has become free of residual substances. As a result, the conductive device remains uncontaminated and has a long service life. The time-averaged power consumption of the technique is less than 2 mW. For resistance heating, a meander heater element can be disposed on a silicon nitride membrane across an etched opening in a silicon chip.

Abstract: Acid/base measuring sensor systems consisting of arrays of basic sensor cells are described which are constructed based on the chemical/electrical response characteristics of poly(aromatic amines). Protonation (doping) or deprotonation (de-doping) of the --N.dbd.sites in the polymers leads to characteristic conductivity vs. concentration curves which can be calibrated to produce reliable, instantaneous readings of the acid/base concentrations at various points in the working environment.

Abstract: A device for sensing ammonia (NH.sub.3) and nitrogen oxide (NO.sub.x) gases comprising: a sensor for detecting said ammonia and said nitrogen oxide gases, said sensor including a substrate and a layer consisting of cuprate material for detection of said ammonia and said nitrogen oxide gases, wherein said layer of cuprate material is selected from the group consisting of Y:Ba:Cu:O (YBCO) and Bi:Sr:Ca:Cu:O (BSCCO); a sensor holder for supporting said sensor; a perforated cap positioned over said sensor, said perforated cap having openings for passage of said ammonia and said nitrogen oxide gases to said sensor; a detection circuit communicating with said sensor for measuring output from said sensor; and a display or recording device connected to said detection circuit for displaying or recording a concentration of said ammonia and said nitrogen oxide gases based on the output from said sensor.

Abstract: According to a method and an apparatus for determining absolute plasma parameters in unsymmetrical radio frequency (RF) low-pressure plasmas, a radio frequency discharge current generated in a plasma reactor is measured in the form of analog signals at a portion of the reactor acting as earth electrode, the analog signals are converted into digital signals, and the desired plasma parameters are evaluated from the digital signals by means of a mathematical algorithm. The apparatus includes a meter electrode which is insulatedly positioned in a flange or recess of the reactor wall which acts at least as part of the earth electrode. The method and apparatus may be used with respect to plasma etching in the technical field of the semiconductor technology.

Abstract: A photoionization detector includes a brittle substrate having a void micromachined therein with a void inlet and a void outlet. First and second electrodes are disposed in the void. An ultraviolet transparent member covers at least a portion of the void in which the electrodes are disposed. A gas sample passes through the void and is exposed to ultraviolet radiation from a UV source. Ionization of the sample is measured as current flowing between the electrodes.

Abstract: A substrate carrying a first electrode and a second electrode, the first and second electrodes being disposed adjacent to one another, the first electrode being disposed between the substrate and a gas-sensitive component, the gas sensitive component comprising an n-type semiconductor, the gas-sensitive component having a resistance that is gas-dependent and temperature-dependent, and the second electrode being disposed between the substrate and a non-gas-sensitive component, the non-gas-sensitive component comprising a n-type semiconductor and a p-type semiconductor, the non-gas-sensitive component having a resistance that is temperature-dependent and that is not gas-dependent and wherein the n-type semiconductor of the non-gas-sensitive component is Ga.sub.2 O.sub.3 and the p-type semiconductor of the non-gas-sensitive component is ZrO.sub.2.

Abstract: A chemical sampling apparatus including an interface between a miniature mobility spectrometer and a gas chromatography system. The apparatus has a gas chromatography an ion mobility spectrometer and an input for inputting a regulated flow of a gas to be analyzed to the gas chromatograph. An interface is positioned between the gas chromatograph and the ion mobility spectrometer. The interface accepts and analyzes eluted gas from the gas chromatograph and selectively inputs the eluted gas to the ion mobility spectrometer only when an eluted gas condition to be analyzed is detected.

Abstract: The isotopic composition of a multiatomic isotope-bearing species such as CO.sub.2 in an analyte is measured by maintaining the analyte in a condition such that isotope-bearing species are present in an excited state and directing light at wavelengths corresponding to transition energies of isotope-bearing species with different isotopes. The interaction between the analyte and light at the different wavelengths is monitored, as by monitoring the optogalvanic effect caused by the light of the different wavelengths. The light may be supplied by a laser including the isotope-bearing species. A stable isotope such as .sup.13 C or .sup.18 O can be used as a tracer in a chemical or biological test and detected using the composition-determining method.

Abstract: A flame based method for analyzing a sample by introducing the sample into a combustible gas mixture, igniting the combustible gas mixture to produce a flame, and detecting a characteristic of the resulting flame to determine the identity and/or concentration of one or more chemical substances in the sample, wherein the combustible gas mixture is generated by water electrolysis. The same method is also utilizable for determining the identity and/or concentration of one or more chemical compounds in the sample. A flame based detector apparatus for analyzing a sample is also described.

Abstract: A method for the ultra-sensitive detection of atmospheric and surface adsorbed nitrocompounds such as propellants, explosives, and nitro-pollutants employs an excimer (ArF) laser operating at or near 193 nm to photofragment the target molecule and facilitate the detection of the characteristic NO fragment, formed from the dissociation of NO.sub.2, by resonance-enhanced multiphoton ionization (REMPI) and/or laser induced fluorescence (LIF) via its A-X, B-X, C-X, and/or D-X electronic transitions. In addition to NO, the detection of other fragments, such as C, CH, C.sub.2, NH and OH, by their ionization and/or prompt emission resulting from 193 nm excitation enhances the analyte identification. The analytical utility of this apparatus and method has been demonstrated on a number of compounds including dimethylnitramine (DMNA), nitromethane, nitrobenzene, orthonitrotoluene, para-nitrotoluene and trinitrotoluene (TNT).

Abstract: A photoionization detector for a gaschromatographic apparatus includes an ionization chamber provided with a polarizing electrode and a collector electrode. The electrodes are mounted on and heated by a base portion of the detector. A lamp with a window spaced from the chamber and mounted on the base portion through supporting means having low thermal conductivity is provided. A gas curtain of a gas that is transparent to the said lamp radiation is provided at least between the window and the ionization chamber and comprises a first portion of substantially still gas acting as thermal insulant and a second portion of flowing gas also acting as sweep gas for the lamp window.

Abstract: In accordance with the method of the present invention, the radio frequency discharge current generated in a plasma reactor is measured in the form of analog signals at a portion of the reactor acting as an earth electrode. The analog signals are converted into digital signals, and plasma parameters are evaluated from the digital signals by means of a mathematical algorithm.

Abstract: Generally, this invention relates to the development of field monitoring methodology for new substances and sensing chemical warfare agents (CWAs) and terrorist substances. It also relates to a portable test kit which may be utilized to measure concentrations of halogenated volatile organic compounds (VOCs) in the field. Specifically it relates to systems for reliably field sensing the potential presence of such items while also distinguishing them from other elements potentially present. It also relates to overall systems and processes for sensing, reacting, and responding to an indicated presence of such substance, including modifications of existing halogenated sensors and arrayed sensing systems and methods.