Abstract: Measurement arrangement for determining a constituent substance or quality parameter of water by thermal decomposition in a reaction module, delivery of a reaction product to a detector, and evaluation of a detector signal for deriving a value of the constituent substance or quality parameter, wherein the reaction module is an elongated vessel having internal heating, and has a head section into which the sample is introduced, a reaction zone, as well as a foot section, from which the reaction product is output, wherein the reaction module, the heating, and means for the supply of samples and carrier gas are configured such that during the operation of the measurement arrangement an outer head temperature is TH?80° C., and an outer foot temperature is TF?150° C. at a maximum temperature in the reaction zone of TMAX?1150° C.

Abstract: The invention relates to a device for producing CO2, N2 and/or SO2 from a sample for a quantitative analysis of the sample, comprising a reactor structure and metals acting in an oxidizing manner or metal oxides in the reactor. According to the invention, the reactor structure has at least two zones through which the sample can flow, which is to say a first zone with reactor metal and reservoir metal, or only reactor metal, and following the first zone, a second zone with reactor metal and reservoir metal, or only reservoir metal, wherein both metals can form oxides, and wherein the ratio of the reactor metal to the reservoir metal in the first zone is greater than in the second zone.

Abstract: A method for monitoring the concentration of water borne substances in an aqueous medium, by introducing a defined amount of the aqueous medium into a gas circulatory system of an analytical apparatus which extends through a high temperature reaction chamber and a measuring chamber. The introducing of the aqueous medium occurs upstream of the high temperature reaction chamber or into it. The aqueous medium is evaporated in the high temperature reaction chamber, the water borne substance with at least one reaction partner in the high temperature reaction chamber reacts to a gaseous reaction product, and a current value of a measured variable is registered, which is a function of the concentration of the chemical species of the reaction product in the gas circulatory system.

Abstract: A method of determining the solubility of a compound in a selected solvent is provided that does not require determination of, or use of, standards having known concentrations of the compound. In one aspect, the method can include preparation of a mixture where not all of a compound is dissolved in the provided solvent, separating undissolved compound from the solvent, and direct determination of the amount of the compound dissolved in the solvent. Methods adapted for use include those where a multiplicity of compounds or solvents are tested in parallel. Devices adapted for these methods are also provided by the present disclosure.

Abstract: The invention provides methods for isolating a target molecule from a sample. In an embodiment, the method involves contacting a sample with a capture agent, the agent comprising a siderophore and a transition metal cation, under conditions wherein the agent is capable of binding a target molecule to form a target molecule-capture agent complex, wherein the target molecule is selected from the group consisting of a phosphorylated molecule, a nitrotyrosine-containing molecule and a sulfated molecule, and separating the target molecule-capture agent complex from the sample, thereby isolating the target molecule from the sample. Also provided are methods for determining the presence of a target molecule in a sample, that involve contacting a sample with a capture agent, the agent comprising a siderophore and a transition metal cation.

Abstract: A dissolved nitrogen concentration monitoring method is used for monitoring a dissolved nitrogen concentration of a cleaning liquid when an ultrasonic wave is irradiated onto the cleaning liquid in which a substrate is dipped. The method includes measuring an amount of increase of a dissolved oxygen concentration of the cleaning liquid resulting from an oxygen molecule generated from a water molecule as a result of a radical reaction caused by ultrasonic wave irradiation. A dissolved nitrogen concentration of the cleaning liquid is calculated from the measured amount of increase of dissolved oxygen concentration based on a predetermined relationship between a dissolved nitrogen concentration and an amount of increase of dissolved oxygen concentration.

Abstract: Process for determination of a water content material, in particular organic carbon content and/or nitrogen, in which an aqueous sample is evaporated and combusted in at least one heating vessel equipped with a heating facility and the combustion product is fed in a transport gas flow to a detector for determination of the concentration of a gaseous compound of the water content material, characterised in that calibration is performed with a predetermined volume of a calibration gas which contains a predetermined concentration of the element corresponding to the water content material, in particular carbon and/or nitrogen.

Abstract: A method of determining the amount of nitrogen in a gas mixture. The constituent gases of the mixture are dissociated and transformed to create a substance that may measured using nondispersive infrared adsorption techniques.

Abstract: A method for monitoring the concentration of water borne substances in an aqueous medium, by introducing a defined amount of the aqueous medium into a gas circulatory system of an analytical apparatus which extends through a high temperature reaction chamber and a measuring chamber. The introducing of the aqueous medium occurs upstream of the high temperature reaction chamber or into it. The aqueous medium is evaporated in the high temperature reaction chamber, the water borne substance with at least one reaction partner in the high temperature reaction chamber reacts to a gaseous reaction product, and a current value of a measured variable is registered, which is a function of the concentration of the chemical species of the reaction product in the gas circulatory system.

Abstract: The present invention provides a method for discriminating an organic farmland from a conventional farmland, comprising; (a) measuring an amount of nitrogen isotope in a soil sample of a farmland; (b) calculating a nitrogen isotope index according to the formula (I) using the resultant nitrogen isotope value and (c) determining whether the farmland belongs to an organic farmland or a conventional farmland. According to the present invention, it is possible to objectively discriminate an organic farmland from a conventional farmland or discriminate an organic crop from a conventional crop.

Abstract: A method for estimating the sulfur content in the fuel of an internal combustion engine equipped with a catalyser capable of storing a quantity of sulfur and NOx groups. The method provides use of a current sulfur concentration value (Sold) and a correction of the current sulfur concentration value (Sold) in order to obtain a new sulfur concentration value (Snew). The method includes the steps of estimating a first value (NOxstored1) of the total quantity of NOx groups stored in the catalyser (11) by means of a model of NOx group production by the engine, estimating a second value (NOxstored2) of the total quantity of NOx groups stored by the catalyser by means of a model of storage of the catalyser, and determining an additive correction coefficient (D) as the difference between the first estimated value (NOxstored1) and the second estimated value (NOxstored2).

Abstract: A method for estimating the sulfur content in the fuel of an internal combustion engine equipped with a catalyser, using a current sulfur concentration value (Sold) and a correction of said current sulfur concentration value (Sold) in order to obtain a new sulfur concentration value (Snew). The method includes the steps of measuring a first time interval (t1-t0) which is actually necessary in order to complete a regeneration process to remove sulfur; determining a quantity (SOxstored) of sulfur stored in the catalyser before the regeneration process to remove sulfur using the current sulfur concentration value (Sold); estimating a second time interval (t2-t0) which is theoretically necessary to complete the regeneration process, on the basis of the estimated quantity (SOxstored) of sulfur stored in the catalyser; and determining a multiplicative correction coefficient as a ratio between the first time interval (t1-t0) and the second time interval (t2-t0).

Abstract: The invention provides a rapid and efficient method and assay for monitoring nitrogen uptake by a plant using a pH indicator. The plant is exposed to medium comprising one or more sources of nitrogen, such as nitrate or ammonia, and a pH indicator. The plant is exposed to the source of nitrogen for a time sufficient for it to be taken up by the plant. As nitrate is taken up from the medium, the medium becomes more basic, that is the pH increases. Conversely, as ammonia is taken up from the medium, the medium becomes more acidic and the pH decreases. The change in the pH of the medium may be optically detected and correlated to the amount of nitrate or ammonia remaining in the medium. Accordingly, the amount of nitrate or ammonia taken up by the plant or remaining in the medium may be determined.

Abstract: Disclosed herein is a method for measuring total organic carbon without the influence of nitrogen components. The method for measuring total organic carbon includes the steps of: (1) adjusting the hydrogen ion concentration of sample water to between pH 4 and pH 6; (2) decomposing organic matter and nitrogen compounds contained in the sample water into carbon dioxide and nitrous acid, respectively, through oxidation and; (3) making the carbon dioxide permeate into measuring water via a gas-permeable part 5a; (4) and measuring the electric conductivity of the measuring water to determine the total organic carbon content of the sample water.

Abstract: A combustion analyzer apparatus and method for combustion analysing a sample, the analyzer comprising a combustion chamber (82) for receiving a sample for combustion therein to form combustion products, and a fluid supply apparatus for supplying fluid(s) into the chamber. The fluid supply apparatus (130-140) comprises a nitrogen oxides (NOx) generating apparatus (140,190,210,240) and is arranged to supply NOx into the combustion chamber. A yield of sulphur dioxide in the combustion products may thereby be improved. The NOx generating apparatus may be operated at a raised working temperature. The NOx generating apparatus may be provided by an ozonator with a supply of nitrogen and oxygen. A Venturi tube arrangement (246) may draw the generated NOx into a (carrier or oxygen) gas line to the combustion chamber. Ozone may be supplied to the combustion products to convert nitrogen monoxide therein to nitrogen dioxide. The NOx and ozone may be supplied by a single device (210,240).

Abstract: Process for determination of a water content material, in particular organic carbon content and/or nitrogen, in which an aqueous sample is evaporated and combusted in at least one heating vessel equipped with a heating facility and the combustion product is fed in a transport gas flow to a detector for determination of the concentration of a gaseous compound of the water content material, characterised in that calibration is performed with a predetermined volume of a calibration gas which contains a predetermined concentration of the element corresponding to the water content material, in particular carbon and/or nitrogen.

Abstract: A method of determining the amount of nitrogen in a gas mixture. The constituent gases of the mixture are dissociated and transformed to create a substance that may measured using nondispersive infrared adsorption techniques.

Abstract: Elemental analysis of a sample is carried out in an oxygen atmosphere in a combustion reactor and the volume of oxygen required for analysis is determined by means of the algorithm Qo=&Dgr;(Qc)  [1] where Qo is the volume of oxygen required and Qc is the weight of the sample to be analyzed and &Dgr;=Qo1/Qc1 where Qo1 is the volume of oxygen necessary for the combustion of a predetermined quantity Qc1 of the sample to be analyzed, the volume of oxygen Qo is then fed in pulsed mode to the combustion reactor, by means of a flow detector.

Abstract: An analyzer compensates for gas flow perturbations by providing a makeup flow of carrier gas to maintain the pressure and/or flow rate of analyte and inert gas through a detector constant such that a accurate determination of a low concentration of an analyte in the presence of a high concentration of a second analyte can be accurately determined. In one embodiment, a carrier gas is introduced through a valve responsive to the detected pressure in the gas flow stream between a scrubber and a subsequent detector for maintaining the pressure constant during an analysis. In another embodiment of the invention, a flow transducer is positioned in the gas flow path between the scrubber and detector and coupled to a flow control valve coupled to introduce carrier gas as a function of detected gas flow such that the flow rate of gas into the detector is maintained constant.

Abstract: A system and method for controlling a microwave heated chemical process is disclosed. Time varying concentrations of some chemical substances within fumes in the microwave oven are monitored to detect concentration variations for which responses are known. Responses to the detected variations are initiated to control the chemical process without terminating the process. Examples of responses include varying microwave radiation energy, initiating safety systems, increased venting of the microwave oven, and so forth.

Abstract: A method is described for determining the presence of a volatile component in a test sample. The method involves use of two separate vessels, one of which is capable of being placed wholly within the other vessel. The test sample is placed in the larger vessel, and an indicator solution is placed in the smaller, inner vessel. Then a gas-tight closure is placed on the top of the outer, larger vessel. The assembly is heated to an elevated temperature, whereby the volatile target analyte which is released from the test sample transfers to the inner vessel and is absorbed by the indicator solution. The indicator solution can be analyzed by means of a calorimeter, spectrophotometer, etc.

Abstract: A process is claimed for the determination of nitrogen content in a nitrogen containing material, said process comprising: a) at least one pre-treatment step, b) at least one distillation step and c) at least one determination step; wherein said distillation step (a) comprises the substeps of: i) diluting a pre-treated sample of a nitrogen containing material with at least one diluting fluid, ii) inputting steam for commencement of steam distillation, and iii) adding at least one alkali compound, whereby the addition of alkali is made 1-60 seconds after commencement of said inputting of steam and said steam distillation and whereby distillate produced during said steam distillation is recovered in an acidic and/or complexing medium.

Abstract: A method for determining constituents in water, in particular the content of organic carbon and/or nitrogen, in which an aqueous sample is evaporated and combusted in at least one heating vessel (154a) provided with a heater (154), and the combustion product is delivered in a transporting gas stream to a detector (142) for determining the concentration of a gaseous compound of the constituent, wherein the heating vessel, or a first heating vessel, at the instant of delivery of the aqueous sample has a temperature below or at most within the range of the boiling temperature of the sample, and after delivery of the sample the temperature is increased, wherein the sample is heated by one and the same heater in a first step from an outset temperature below the boiling temperature to an evaporation temperature, and in a second step to a substantially higher temperature, and the combustion product is kept in closed circulation during the analysis.

Abstract: A system and method for controlling a microwave heated chemical process is disclosed. Time varying concentrations of some chemical substances within fumes in the microwave oven are monitored to detect concentration variations for which responses are known. Responses to the detected variations are initiated to control the chemical process without terminating the process. Examples of responses include varying microwave radiation energy, initiating safety systems, increased venting of the microwave oven, and so forth.

Abstract: A method for microwave assisted chemical processes is disclosed that comprises applying sufficient microwave radiation to a temperature-monitored mixture of reagents, with at least one of the reagents being thermally responsive to electromagnetic radiation in the microwave range, and based on the monitored temperature, to maintain the added reagents at or closely about a predetermined temperature while substantially avoiding thermal dilution (or before substantial thermal dilution can occur) that otherwise would have been caused by the addition of the reagents to one another.

Abstract: To estimate nitric acid ions and nitrous acid ions in a sample solution, a method is proposed which comprises the steps of (a) feeding both the sample solution and a reducing agent to an acidic solution which is flowing in a thin pipe; (b) positively mixing the sample solution and the reducing agent and thus reacting the same in a given portion of the pipe; (c) leading the reacted solution to a gas/liquid separator thereby to separate a gaseous phase from the reacted solution; and (d) estimating the nitric acid ions and nitrous acid ions in the gaseous phase.

Abstract: Nitrosyl (FeII) hemoglobin can be detected in biological samples, using a method which involves injections of samples into a photolysis cell, prior to detection of chemiluminescence generated by the reaction between nitric oxide and ozone. This method is useful for monitoring the levels of nitric oxide bioactivity in both normal physiological states, and disease states, such as septic shock, atherosclerosis, thrombosis, hyperhomocysteinemia, pulmonary hypertension, malignancy, infections and central nervous system disorders.

Abstract: A method for microwave assisted chemical processes is disclosed that comprises applying sufficient microwave radiation to a temperature-monitored mixture of reagents, with at least one of the reagents being thermally responsive to electromagnetic radiation in the microwave range, and based on the monitored temperature, to maintain the added reagents at or closely about a predetermined temperature while substantially avoiding thermal dilution (or before substantial thermal dilution can occur) that otherwise would have been caused by the addition of the reagents to one another.

Abstract: An efficient method is proposed for the determination of the concentration of nitrogen in an indirect-transition compound semiconductor such as gallium phosphide added as an isoelectronic trap. The method utilizes the fact that a good correlation of proportionality is held between the nitrogen concentration and the difference .DELTA..alpha.(=.alpha..sub.N -.alpha.) in the absorption coefficient of light of a wavelength identical with the wavelength .lambda..sub.N due to the excitons under constraint in the isoelectronic trap between the semiconductors with (.alpha..sub.N) and without (.alpha.) addition of nitrogen. A working curve is presented between the nitrogen concentration determined by the method of SIMS and the value of .DELTA..alpha..

Abstract: A sensor to detect and quantify urea in fluids resulting from hemodialysis procedures, and in blood and other body fluids. The sensor is based upon a chemiresistor, which consists of an interdigitated array of metal fingers between which a resistance measured. The interdigitated array is fabricated on a suitable substrate. The surface of the array of fingers is covered with a coating containing the enzyme urease which catalyzes the hydrolysis of urea to form the ammonium ion, the bicarbonate ion, and hydroxide-chemical products which provide the basis for the measured signal. In a typical application, the sensor could be used at bedside, in conjunction with an appropriate electronics/computer system, in order to determine the hemodialysis endpoint.

Abstract: To estimate nitric acid ions and nitrous acid ions in a sample solution, a method is proposed which comprises the steps of (a) feeding both the sample solution and a reducing agent to an acidic solution which is flowing in a thin pipe; (b) positively mixing the sample solution and the reducing agent and thus reacting the same in a given portion of the pipe; (c) leading the reacted solution to a gas/liquid separator thereby to separate a gaseous phase from the reacted solution; and (d) estimating the nitric acid ions and nitrous acid ions in the gaseous phase.

Abstract: A method of monitoring compliance of a patient that has been placed on a medication maintenance program with a prescribed medication dosage by determining a normalized urine medication concentration. An unadulterated urine sample is obtained from the patient. The urine medication concentration and urine specific gravity are measured. The normalized urine medication concentration is calculated as a function of the measured medication concentration in the urine and the urine specific gravity. The calculated normalized urine medication concentration is compared with an expected medication concentration value for the patient for the maintenance program prescribed to determine any significant differences therebetween as an indication of noncompliance. Alternatively, a urinary-parameter normalized urine medication concentration is calculated as a function of the measured medication concentration in the urine, the urine specific gravity and at least one selected pharmacokinetic parameter of the medication.

Abstract: This invention provides a process for determining the nitrogen content of a sample involving (a) combusting the sample in a combustion reactor in the presence of oxygen, which oxygen is introduced into the combustion reactor in pulse form; (b) reducing the resulting combustion gases by flowing them in a flow of helium or other noble carrier gas through a Cu-containing reduction reactor; (c) performing the steps of (i) making anhydrous in a water trap the reduced gases, (ii) flowing the reduced gases through a gas-chromatographic column in order to carry out a gas-chromatographic separation of N.sub.2 from CH.sub.4 possibly present within the reduced gases, and (iii) removing CO.sub.2 from the reduced gases using a CO.sub.2 trap, with the proviso that step (i) immediately precedes step (ii); and (d) analyzing the resulting gases by detecting thermal conductivity.

Abstract: Sample water is supplied to an oxidative decomposer, heated to 90.degree. C. under presence of a photooxidation catalyst, and irradiated with ultraviolet radiation by a low pressure mercury lamp while being supplied with air, to cause photooxidative decomposition reaction. After the reaction, nitric acid ions are measured with an absorption photometer at a wavelength of 220 nm. Then, a color developer is added to the sample water, and the colored solution is employed for measurement of phosphoric ions with the absorption photometer at a wavelength of 880 nm.

Abstract: A device for monitoring the boron content of the borophosphosilicate, BPSG. The BPSG is obtained by the oxidation of silane, of diborane and of phosphine in a reactor, starting with a first, diborane/silane gas mixture and a second, phosphine/silane gas mixture by monitoring the ratio .rho.=diborane/(diborane+silane) of the mixture resulting from the mixing of the first and second gas mixtures. Monitoring of the boron content is obtained by measuring the density of the first mixture, determining the amount of residual hydrogen in the first mixture and modulating the mass flow rate of the first mixture in response to the calculated ratio .rho..

Abstract: Nitric oxide, nitrosonium, S-nitrosothiols, and S-nitroso-proteins can be detected in biological samples, using a method which involves injection of samples into a photolysis cell, prior to detection of chemiluminescence generated by the reaction between nitric oxide and ozone. To detect S-nitrosothiols and S-nitroso-proteins separate aliquots of the same samples are subjected to pretreatment with mercurous ion, and a protein-precipitating agent, respectively, and the resulting nitric oxide signals are compared to those generated by untreated samples. This method is useful for monitoring the levels of nitric oxide bioactivity in both normal physiological states, and disease states, such as septic shock, atherosclerosis, thrombosis, hyperhomocysteinemia, pulmonary hypertension, malignancy, infections and central nervous systems disorders.

Abstract: An apparatus for measuring the total content of organic carbon (TOC) and nitrogen (TN) in water. The TOC value is correctly determined as the sum of the liquid, dissolved, and solid substances of a specimen of the water. The apparatus includes a NDIR gas analyzer for simultaneously measuring the concentration of CO.sub.2 and NO gas components with a phase separator, a thermal reactor, a condenser, and two amplifiers for the pneumatic signals of the receivers with an indicator for the measured TOC and TN concentrations. The specimen is split into a gaseous part and a liquid part in the phase separator. The gaseous part which essentially contains the inorganic fraction of carbon, the TIC fraction, in the form of CO.sub.2 gas is cooled in a condenser until a substantial fraction of its water vapor content is separated in the condenser by condensation. The dried gaseous part is directed via the comparison vessels as comparison gas.

Abstract: An NO.sub.x analyzer capable of reducing maintenance operations for removing solid substances from the analyzer, and for obtaining an analytical value of improved reliability for sample gases flowed through the analyzer is provided. A sample gas supply passage on the downstream side of an NO.sub.x convertor is provided with a first capillary therein; a sample gas supply passage between the first capillary and the NO.sub.x convertor is provided with an overflow passage having a second capillary branch connected therewith; a sample gas supply passage on a downstream side of the first capillary is provided with a diluent air supply passage having a third capillary therein and also branch connected with the sample gas supply passage. At least the confluence of the first capillary, the second capillary, and the diluent supply passage with the sample gas supply passage is arranged within a heating zone of the NO.sub.x analyzer.

Abstract: The invention relates to a method for measuring of the total content of organic carbon and of nitrogen in water. The total organic carbon value is obtained correctly as the sum of the liquid, dissolved, and solid materials of a sample of the water. The device comprises a non-dispersive infrared (NDIR) gas analyzer for the simultaneous measurement of the concentration of the gas components carbon dioxide CO.sub.2 and nitrogen oxide NO. The NDIR gas analyzer includes a phase separator (50), a thermal reactor (52), a double cooler (70), two valves (54, 56), as well as two amplifiers (58, 60) for the pneumatic signals of the receiver detectors (30, 36) with a display (62. 64) for the measured concentrations, total organic carbon and total nitrogen. The sample is split in a phase separator (50) into a gaseous and into a liquid part. The gaseous part, which comprises substantially the inorganic part of the carbon, the total inorganic carbon part in the form of carbon dioxide CO.sub.

Abstract: A method for analyzing total bound nitrogen in a sample and providing an output data of total bound nitrogen and constituent compounds (nitrate and nitrite) is disclosed. The total nitrogen bound method provides a discrete sample through a furnace in the presence of continuous flow of water as carrier as well as oxygen carrier gas, resulting in the oxidation of the nitrogen compounds to nitric oxide. The nitrate method involves a discrete sample with water as a carrier provided to a sparge tank. The nitrite is catalytically reduced to nitric oxide in the presence of tartaric acid and ascorbic acid. The nitrate method involves a first conversion to change the nitrate to a nitrite. The first conversion occurs in the presence of a copper-cadmium catalyst causing the formation of the NO.sub.2. The nitrile is subsequently converted into NO. The nitric oxide produced in each of the three methods is measured in a chemiluminescent nitrogen detector.

Abstract: A method for measuring of the total content of organic carbon and of nitrogen in water. The total organic carbon value is obtained correctly as the sum of the liquid, dissolved, and solid materials of a sample of the water. The device comprises a non-dispersive infrared (NDIR) gas analyzer for the simultaneous measurement of the concentration of the gas components carbon dioxide CO.sub.2 and nitrogen oxide NO. The NDIR gas analyzer includes a phase separator (50), a thermal reactor (52), a double cooler (70), two valves (54, 56), as well as two amplifiers (58, 60) for the pneumatic signals of the receiver detectors (30, 36) with a display (62. 64) for the measured concentrations, total organic carbon and total nitrogen. The sample is split in a phase separator (50) into a gaseous and into a liquid part. The gaseous part, which comprises substantially the inorganic part of the carbon, the total inorganic carbon part in the form of carbon dioxide CO.sub.

Abstract: A test kit for determining the relative level of nitrogen of a user who is involved in a health program where diet and exercise are monitored and adjusted for optimizing physical development, the system includes a plastic stick having a first reagent zone on which is included a reactant such as urease, and a pH indicator such as bromthymol blue, and a second reagent zone on which is included a reactant indicator such as sodium nitroprusside used in conjunction with color chart blocks representing a range of urea nitrogen and ketone concentrations, wherein the user's urine nitrogen and ketone content can be determined by comparing the altered color of the reagent zone of an exposed test strip to the color chart blocks and compared with a personal baseline level, developed from a number of tests under controlled conditions, for determining the present protein nitrogen turnover and approximate balance, and the body fat metabolism.

Abstract: A method of determining nitrogen in various nitrogenous materials, wherein the materials are combusted by being brought into contact with a solid metallic catalytic mass, in the presence of an oxygenated gas, so as to convert the nitrogen into NO. This is then determined, preferably by chemiluminescence or by optical interferometry. The method is improved by adding a halide of an alkali metal or an alkaline earth metal to the materials prior to combustion.An apparatus comprising an oven (1,2,2') charged with catalytic mass (4), which can be a wire acting as a heating element, and provided with an oxygen inlet (6). The catalytic mass is a non-oxidizable ferrous alloy or a metal of the Pt group.

Abstract: A system and method for determining the concentration of nitrate ions in a nitrate ion-containing water sample which also contains chloride ions and bicarbonate ions is disclosed. The potentially interfacing chloride ions are suppressed by reaction with a cation exchange resin in the silver form. The potentially interferring bicarbonate ions are suppressed by reaction with a cation exchange resin in the hydrogen form. The sample, after having been treated with the two resins is passed into a conductivity cell with the conductivity being directly related to the nitrate ion concentration of the sample. The device and method find advantageous application in automated systems for monitoring and controlling water treatment facilities.

Abstract: The present invention relates, a compound for use with selective detectors of the semiconductor resistance type which detect for nitrogenous reducing gases in the atmosphere, especially ammonia and gases containing NH and/or NH.sub.2 groups, said compound comprising the gallium nitride and, oxynitrides of tetrahedral structure according to the general formula: ##EQU1## in which: .quadrature. represents a hole, and 0.ltoreq.x.ltoreq.0.3.

Abstract: A system for the detection of trace components in a gas by a process involving the ionization of such trace components and intermittently adding to the gas, a reactant gas which converts some of the components to more readily ionizable forms.

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: An improved process for quantitatively determining nitrogen content in a wide variety of materials. The process avoids the use of conventional catalysts, is simpler and faster than previous techniques, and results in a very high degree of accuracy. The process involves the use of a reagent solution prepared by mixing hydrogen peroxide and concentrated sulfuric acid. The digestion process also enables quantitative determination of various elements other than nitrogen.

Abstract: An ion mobility spectrometer for analysis of a gaseous sample wherein only nitrogen and phosphorus containing molecules of the sample are ionized. The spectrometer is of the type having an ion source for ionizing the sample gas and a shutter for gating ions into a drift region, wherein an electric field gradient exists. The ion source includes a bead which comprises a thermally stable material, such as a ceramic or glass, having an alkali metal compound on its surface. The bead is immersed in a gaseous mixture of hydrogen and air, and is heated to a temperature of 200.degree.-1000.degree. C. The bead selectively ionizes phosphorus and nitrogen containing molecules of the sample upon contact with the bead.

Abstract: In one exemplar embodiment, a chemiluminescent nitrogen detector for detecting chemically-bound nitrogen in an organic compound is provided in which a discrete sample of the organic compound containing the chemically-bound nitrogen is injected into a high temperature furnace where the sample is pyrolyzed at extremely high temperatures in an oxygen rich atmosphere to form nitric oxide. The pyrolysis gases, including nitric oxide is then applied to a drying means for eliminating a substantial quantity of water vapor from the carried pyrolysis gases to insure that the dew point of the gases is below the operating temperature of a nitric oxide and ozone reaction chamber. The nitric oxide and ozone are mixed in a reaction chamber to form metastable nitrogen dioxide which instantaneously relaxes to its ground state with a resulting photo-emission of light energy.