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 fiber optic chemical dosimeter system detects the presence of hydrazine fuels and nitrogen tetroxide and nitrogen dioxide gases that are used at rocket launch sites using colorimetric sensors that react selectively with the gases and then absorb laser light communicating through a fiber optic network having a conventional diode laser source transmitting interrogation pulses to a plurality of distributed sensors covering a wide area launch site, the sensor being reactive cladding or distal end types both providing optical reflective returns well suited for reflective near infra-red and visible-red laser interrogation by an optical time domain reflectometry monitor which compares the interrogated laser pulses with sensor returns to determine the extent and location of gas cloud exposures over the distributed wide area.

Abstract: An air sampling system and a calibration system therefor are disclosed for use therewith in order to provide air sampling for, for example, environmental tobacco smoke aerosol in a portable personal air sampling system. The air sampling system utilizes a sampler head having a manifold block which allows for the collection of air for studying both the particulate and vapor phases of environmental tobacco smoke aerosol using only a single pump. An air flow calibrating system is utilized to measure and calibrate the air flowing through the two collection devices used in connection with the manifold block in which the air flow through the two sampling assemblies is simultaneously read out.

Abstract: A gas sensor for use in monitoring gases such as H.sub.2 S, NO.sub.2 or SO.sub.2 comprises a film or layer of non-protonated polyaniline as the gas sensing material.

Abstract: A quantitative assay for creatinine has been developed in which creatinine is reacted with 3,5-dinitrobenzoate under alkaline reaction conditions to produce a fluorophore product which has excitation and emission maxima near 410 nm and 475 nm, respectively. Alternatively, 3,5-dinitrobenzoyl chloride or methyl-3,5-dinitrobenzoate may be employed as reagents. The chemical reactions proceed in the presence of Group IA bases and/or quaternary alkyl ammonium hydroxides under aqueous, nonaqueous and mixed solvent conditions. Detection limits for creatinine are well below one micromole per liter. Conversely, the reactivity of creatinine and/or base with 3,5-dinitrobenzoate may be employed to quantify 3,5-dinitrobenzoate by fluorescence intensity measurements. The chemical assay is readily adaptable to reagent pad and dry-layered coating technologies employing fluorescence detection/quantitation.

Abstract: A process is provided for determining the concentration of a gas in a molten metal by a carrier gas, which can be pumped to at least one analyzer, either in direct route for calibration, or for measuring through a measuring circuit with a measuring probe immersed in the molten metal, wherein the carrier gas effects a gas exchange with the molten metal, and this gas mixture is pumped to the analyzer for measurement. In order to obtain an accurate and quick reading of the concentration of a gas in a molten metal, the carrier gas is pumped for one segment of a measuring cycle directly to the analyzer for calibration, as well as to the measuring circuit for purging and for uptake of the gas to be measured, so that the gas to be measured is ready for the analyzer.

Abstract: A sensor device is disclosed for identification of a gaseous component in a gaseous or liquid sample. The sensor device comprises an optode membrane having sensitivity for the gaseous component to be identified. The optode membrane incorporates two ionophores, at least one of which is a chromoionophore capable of changing absorption spectrum. The sensor device further comprises a hydrophobic gas-permeable membrane, one side of which is positioned upon the optode membrane to prevent direct contact of the optode membrane with the liquid or gaseous sample while still permitting passage of the gaseous component to be identified. As a result, ionic compounds incapable of passing through the lipophilic gas-permeable membrane do not interfere with the identification process leading to a highly sensitive sensor.

Abstract: A system and method are provided for minimizing the effects of background signals in masking signals indicating the presence of substances to be detected such as contaminants in materials moving rapidly along a conveyor. The contaminants detected may include nitrogen containing compounds and hydrocarbons. The system and method of the present invention minimize during detection of the presence or absence of such substances, the number of falsely positive indications of the presence of such substances due to background signals and changes in background signals. The substances detected are divided into first and second sample portions and the respective portions are heated. The first heated portion is mixed with ozone to cause a chemical reaction therewith in order to generate radiation by chemiluminescence having characteristic wavelengths related to substances in the first portion.

Abstract: Appendicitis can be detected in human beings suspected of having appendicitis by determining a threshold level of 10 mg/liter of .sigma.-hydroxyhippuric acid in the urine of such humans. This threshold level can be determined by qualitative, semiquantitative, or quantitative methods including HPLC (high pressure liquid chromatography), TLC (thin layer chromatography), radioimmunoassay, colorimetric tests, NMR (nuclear magnetic resonance), mass spectrometry, electrophoresis, monoclonal antibody tests, and enzymatic tests. The absence of appendicitis can be established by the presence of .sigma.-hydroxyhippuric acid in concentrations less than about 10 mg/liter in a urine sample.

Abstract: An explosive detection screening system used for the detection of explosives and other controlled substances such as drugs or narcotics. The screening system detects the relatively volatile and non-volatile vapors and/or particulate matter emissions from the aforementioned substances and reports that they are present on an individual or object and the concentration of each substance detected. The screening system comprises a sampling chamber for the collection of the vapor and/or particulate emissions, a concentration and analyzing system for the purification of the collected vapor and/or particulate emissions and subsequent detailed chemical analysis of the emissions, and a control and data processing system for the control of the overall system.

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: A base modifier is added to a pyridine/base reagent composition to improve the ability to detect halogenated hydrocarbons like TCE and chloroform. The base modifier is an organic base which facilitates formation of a stable final reaction product. New bases are also combined with pyridine.

Abstract: A method is disclosed for controlling the hardness of a polyurethane foam by introducing an aroma chemical into the reaction mixture to form a polyurethane foam according to a desired hardness to be attained. The aroma chemical can be selected based on the empirical formula:log.sub.e (hardness of foam)=1.87(polarity/molecular weight).sup.0.

Abstract: A multilayer analytical element has been prepared for accurate and rapid colorimetric determination of ethanol in aqueous specimens using alcohol dehydogenase and an oxidized nicotinamide coenzyme. The element includes two reagent layers beneath a porous spreading layer. The element also contains niacinamide in one or more layers to reduce the interference from alcohols other than ethanol.

Abstract: A multilayer analytical element has been prepared for accurate and rapid colorimetric determination of ethanol in aqueous specimens using alcohol dehydrogenase and an oxidized nicotinamide coenzyme. The element includes at least one reagent layer beneath a porous spreading layer. This reagent layer has a crosslinked polymeric binder prepared, in part, with a polymerizable monomer having a halomethylcarbonyl, haloethylcarbonyl, halomethylsulfonyl or haloethylsulfonyl group. Alcohol dehydrogenase is in a layer of the element for reaction with the analyte.

Abstract: In the method for the determination of water, the sample is admixed with a molar 1:1 adduct of sulphur dioxide with an amine having a pK.sub.A of more than 6, dissolved in an aprotic solvent, and is oxidized with iodine.

Abstract: A system for injecting liquid into containers moving through an inspection station at variable speeds without spilling liquid over the outside of, or between, the containers for inspecting the containers for the presence of certain substances such as potential contaminants, such as ammonium salts or amine salts in glass or plastic bottles. The movements of each container is tracked with sensors upstream of a high speed injector, and one or more nozzles is timed to inject liquid in a narrow, high velocity stream only while the top opening of a container is under the nozzle(s). The liquid is employed to enhance liberation of vapors from within the containers for detection of the contaminants in the containers.

Abstract: Apparatus for preconcentrating trace amounts of organic vapors in a sample of air for subsequent detection, comprising a metallic substrate; a thin film of fullerenes deposited on the metallic substrate for adsorbing the organic vapors on the thin film of fullerenes, thereby preconcentrating the organic vapors; and apparatus for heating the metallic substrate to a predetermined optimum temperature for desorbing the vapors from the thin film of fullerenes to form desorbed organic vapors for subsequent detection.

Abstract: A method of testing for the presence of dibromonitrilopropionamide in a sample, which comprises adding to the sample, under alkaline conditions and in the presence of magnesium ions, a phenolic or anilinic compound that generates a colour; and observing the resultant colour. The appropriate reagents may be formulated as a kit, e.g. using pyrocatechol as the phenolic compound.

Abstract: Disclosed is a method and apparatus for sampling and determining the presence of certain substances, such as residues of contaminants in containers. The method includes steps of: injecting compressed air into said containers in order to displace at least a portion of the contents thereof; evacuating a sample of the container contents so displaced by applying suction thereto; and analyzing the sample evacuated to determine the presence or absence of the certain residues therein. The compressed air is injected through a nozzle into an opening in the containers to displace a portion of the container contents and form a sample cloud outside of the container. The sample cloud is then at least partially evacuated by suction and the sample is analyzed for the presence of contaminants such as nitrogen containing compounds or hydrocarbons. In one embodiment about 90% of the sample evacuated is diverted from the analyzer and recirculated into the air injector.

Abstract: A process is provided for analyzing and detecting in an aqueous based mobile phase sample one or more N-nitroso compounds, which process includes the steps of injecting the aqueous based sample into a high pressure chromatograph to produce a liquid effluent where the nitroso compounds are resolved and separated, mixing the liquid effluent with an inert gas to produce a biphasic gas/liquid mixture, irradiating the biphasic mixture under ultraviolet irradiation to convert the nitroso compounds to nitric oxide gas, and detecting the nitric oxide produced.

Abstract: An apparatus and method for the sensitive detection of atmospheric and/or surface absorbed nitrocompounds has been developed. The apparatus and method may be employed to detect the presence or absence of propellants, explosives, and nitropollutants. The unique feature herein is that the apparatus and method employ one laser operating at or near 226 nm. The laser photofragments the target molecule and facilitates the detection of the characteristic NO fragment, by resonance-enhanced multiphoton ionization (REMPI) and/or laser-induced-fluorescence (LIF) via its A.sup.2 .SIGMA..sup.+ -X.sup.2 II.sub.i transitions. The analytical utility of this apparatus and method has been demonstrated on numerous compounds, such as, DMNA, nitromethane, nitro-benzene, TNT, and RDX. With the present system, a limit of detection of 8 and 24 ppb is obtained for RDX and TNT, respectively, using only 100 micro-Joules per pulse of laser energy.

Abstract: A sensor device includes ultra-large pore crystalline material M41S as a selective detecting element, and a measuring element for quantifying physical, chemical or biological events which occur within the crystalline material. The crystalline material may also contain an additional selective detecting component within its pores.

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 new optically active amino acid derivatives of the general formula (I) ##STR1## in which n, R, R.sub.1, R.sub.2, R.sub.3, X and A have the meaning given in the description, which amino acid derivatives contain sulphoxide or sulphone groups, to two basic synthetic routes for the preparation from sulphur-containing amino acids, to the polymerization of these monomers and to the use of the polymers as optically active adsorbents for chromatographic resolution of racemates to give the enantiomers.

Abstract: Biological samples are analyzed for benzodiazepines in a single isocratic analysis using a chromatographic column system containing an immobilized enzyme reactor which cleaves glucuronic acid-conjugated benzodiazepines, an anion exchange column, a hydrophobic cation exchange column and a reverse-phase analytical column. Preferred methods of performing the analysis further involve the use of a hydrophobic cation exchange precolumn prior to the anion exchange column. The system readily lends itself to automation, automatic periodic sampling and benzodiazepine identification and quantification. The system is particularly well adapted to the determination and identification of benzodiazepines in urine samples.

Abstract: A method and apparatus for sampling and determining the presence of certain substances, such as residues of contaminants in containers. The method includes steps of: injecting compressed air into said containers in order to displace at least a portion of the contents thereof; evacuating a sample of the container contents so displaced by applying suction thereto; and analyzing the sample evacuated to determine the presence or absence of the certain residues therein. The compressed air is injected through a nozzle into an opening in the containers to displace a portion of the container contents and form a sample cloud outside of the container. The sample cloud is then at least partially evacuated by suction and the sample is analyzed for the presence of contaminants such as nitrogen containing compounds or hydrocarbons. In one embodiment about 90% of the sample evacuated is diverted from the analyzer and recirculated into the air injector.

Abstract: A sensor detects analytes in a fluid medium by measuring the conductivity of a layer on a carrier with the layer contacting an electrode pair. The layer interacts with the analyte and is improved in that the sensor has a long-term stability and the indication provided by the sensor is completely reversible. The layer is a fullerene layer.

Abstract: A method for the detection of at least one polyamine associated with bacterial infection, which comprises contacting a sample suspected of containing polyamine-associated bacteria in aqueous medium at alkaline pH with indigo carmine and dimethyl sulfoxia and observing whether a blue color develops in five minutes indicating the presence of polyamine.

Abstract: A paint or coating composition and method for detecting vapor or liquid reactants, such as ammonia. The composition is composed of ethyl cellulose as a binder, a filler, such as amorphous silica, and a dye, such as bromophenol blue. The composition serves as a passive detector for vapor or liquid reactants when applied to selected surfaces as a paint. The composition is capable of detecting extremely low concentrations of vapor. Further, the composition is capable of regenerating to its original color, thereby providing repeated detection capability.

Abstract: A method and apparatus for sampling and determining the presence of certain substances, such as residues of contaminants in containers. The method includes steps of: injecting compressed air into said containers in order to displace at least a portion of the contents thereof; evacuating a sample of the container contents so displaced by applying suction thereto; and analyzing the sample evacuated to determine the presence or absence of the certain residues therein. The compressed air is injected through a nozzle into an opening in the containers to displace a portion of the container contents and form a sample cloud outside of the container. The sample cloud is then at least partially evacuated by suction and the sample is analyzed for the presence of contaminants such as nitrogen containing compounds or hydrocarbons. In one embodiment about 90% of the sample evacuated is diverted from the analyzer and recirculated into the air injector.

Abstract: An on-line mass spectrometric method and apparatus for the determination of the isotopic composition of at least oxygen, hydrogen and nitrogen in a compound or mixture of compounds. A mixture contained in syringe 6 is injected through injector 7 on a chromatographic column 1. Compounds eluting from the column 1 pass into a catalytic reactor 14 containing carbon and are decomposed to produce carbon monoxide, molecular nitrogen, and molecular hydrogen. These gases are analyzed by an isotope-ratio mass spectrometer 4 so that the isotopic composition of the oxygen, nitrogen and hydrogen comprised in the original compound can be determined. A second chromatographic column 24 may be provided to separate carbon monoxide and nitrogen before they are passed into the spectrometer 4, thereby allowing a low resolution spectrometer to be used for the analysis of both gases at m/e 28 daltons.

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: This invention relates to a compact and portable detection apparatus for ro-aromatic based chemical compounds, such as nitrotoluenes, dinitrotoluenes, and trinitrotoluene (TNT). The apparatus is based upon the use of fiber optics using filtered light. The preferred process of the invention relies upon a reflective chemical sensor and optical and electronic components to monitor a decrease in fluorescence when the nitro-aromatic molecules in aqueous solution combine and react with a fluorescent polycyclic aromatic compound.

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: Control reagents an oxidant or a hydroxylamine compound together with other ingredients, the most important of which is a known amount of the analyte for which the reagent acts as a control.

Abstract: In a color reaction method for detecting particular classes of explosives, a sample from a suspect source is subjected serially to the indicated reagents in the liquid phase, the reagents after the first being applied only if no color reaction has been obtained in the preceding test. The second and third reagents only are applied in presence of the preceding reagent(s). The first reagent is an alkaline solution of a diazotizable aminoaromatic azo-dye precursor, which detects nitroaromatic explosives. The second reagent is a strongly acidic reagent containing a nitrate to nitrite ion reducing agent and a diazo-coupler, which detects organic nitrates and nitramines. The third reagent is zinc powder suspended in a liquid, which detects inorganic nitrates. The fourth reagent is an aniline salt in a homogeneous strongly acidic solution including a water-miscible organic solvent, which detects chlorates and bromates. The invention includes also a test kit for use in the method.

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 and kit for estimating the amount of methyl anthranilate includes obtaining a sample suspected of having methyl anthranilate, acidifying the sample with a strong acid, adding sodium nitrite to the acidified sample producing nitrous acid which in the presence of methyl anthranilate produces a diazonium ion. The method further comprises a step of adding sulfamic acid which removes excess nitrous acid from the sample, followed by the addition N-(1-naphthyl) ethylenediamine which reacts with the diazonium ion to form a colored complex which is color responsive which is then compared to standards prepared using known amounts of methyl anthranilate. The kit provides the a sample holder and vials of ingredients and standards to practice the method.

Abstract: A method and apparatus are set forth for enhancing the concentration of oxides of nitrogen in the preferred embodiment. A permeable membrane is formed into a tube placed in a container. A sample containing bound nitrogen in placed in a container in contact with the tube. A carrier gas is swept through the tube in contact with the wall of the tube. This enables hydrophobic gases such as oxides of nitrogen to migrate through the wall of the tube and they are swept into a detection system. If desired, they can be permitted to accumulate in the wall for an interval and the carrier gas can be switched from off to on to achieve peak concentration for delivery to a bound nitrogen analytical device. Other hydrophobic gases such as oxides of sulfur can likewise be identified by sulfur analyzer. This enables an increase in trace concentration.

Abstract: NO.sub.2 and other electron acceptor gases can be detected at 5 volume parts per million by tetrathiafulvalene TTF. The TTF may be incorporated in a polystyrene film, which changes its infra-red spectrum and conductivity upon exposure to such gases.

Abstract: A method for determining the concentration of a tracer, e.g. nitrogen-bearing marker dye, in a hydrocarbon liquid, e.g. gasoline. In the present method, a sample of the marked hydrocarbon liquid which is to be analyzied is prepared by adding a known volume of a nitrogen-bearing, "internal standard" thereto. The sample is then heated, preferably in a gas chromatograph, to vaporize, separate, and measure the dye and the internal standard. These measurements provide a ratio which is matched or compared to a predetermined, reference ratio which, in turn, is representative of a known concentration of the dye in the sampled hydrocarbon.

Abstract: The process of detecting the presence on a surface of at least one of bis(2-chloroethyl)sulfide and bis(2-chloroethyl)imine, including (a) providing a solution comprising at least one dyestuff selected from the group consisting of brilliant blue R, guinea green B, neutral red, and lissamine green B, which at least one dyestuff is capable of fluorescing and is capable, when applied as a solution, of forming an adduct with at least one of bis(2-chloroethyl)sulfide and bis(2-chloroethyl)imine when present on a surface, which at least one adduct, is capable of fluorescing in a spectral range which is different from that of the corresponding at least one dyestuff; (b) applying the solution to the surface; (c) irradiating the surface onto which the solution has been applied with light having a wavelength effective to excite the at least one dyestuff and, when present, the at least one adduct, and induce light emission by fluorescence therefrom; (d) measuring the wavelength of the light emitted from the surface; and

Abstract: 2-amino-3-methyl-1-naphthalenecarbonitriles of the formula: ##STR1## wherein R is alkyl of from 1 to 6 carbon atoms, halogen, cyano, or hydrogen are prepared by pyrolizing a by-product of a SAN or ABS manufacturing process of the formula: ##STR2## wherein R is alkyl of from 1 to 6 carbon atoms, halogen, cyano, or hydrogen.In another respect, this invention is a process for identifying aldehydes comprising: (a) contacting 2-amino-3-methyl-1-naphthalene-carbonitrile with aldehydes to form an UV-absorbing imine, and (b) analyzing the imine using conventional analytical techniques to identify the presence of the imines.

Abstract: The present invention is directed to a process for the analytical determination of acetylcyanamide in urine. It involves (a) the separating of acetylcyanamide at from a urine matrix and/or an extract which is obtained from a urine matrix by ion exchange chromatography or reverse phase high performance liquid chromatography (HPLC), and (b) detecting the acetylcyanamide at a wavelength of 220 nm. The matrix or the extract of it is cleaned by treatment with activated carbon at pH 7 to 13, and the acetylcyanamide may be extracted from the cleaned matrix or its extract at pH 0.5 to 3.5, e.g. by liquid-liquid extraction of the acetylcyanamide. This is carried out by means of water-insoluble, organic solvent such as ethyl acetate or diethyl ether.

Abstract: A paint or coating composition and method for detecting vapor or liquid reactants, such as ammonia. The composition is composed of ethyl cellulose as a binder, a filler, such as amorphous silica, and a dye, such as bromophenol blue. The composition serves as a passive detector for vapor or liquid reactants when applied to selected surfaces as a paint. The composition is capable of detecting extremely low concentrations of vapor. Further, the composition is capable of regenerating to its original color, thereby providing repeated detection capability.

Abstract: A portable fiber optic detector that senses the presence of specific target chemicals by electrostatically attracting the target chemical to an aromatic compound coating on an optical fiber. Attaching the target chemical to the coated fiber reduces the fluorescence so that a photon sensing detector records the reduced light level and activates an appropriate alarm or indicator.

Abstract: A method for assaying Bronopol or Permachem, i.e. 2-bromo-2-nitro-1,3-propanediol or 2,2-dibromo-2-nitroethanol, or a derivative thereof in a sample, comprises adding to the sample a diazo compound which reacts with the compound under test to form a colored species, and determining the presence and, if desired, concentration of the species colorimetrically.

Abstract: Method for the continuous determination of dimethylformamide and dimethylamine in aqueous solutions, especially in effluents. A method for the continuous determination of the amount of dimethylformamide in a solution containing dimethylformamide, the amount of dimethylamine in a solution containing dimethylamine, and the combined amount of dimethylformamide and dimethylamine in a solution contained in aqueous solutions, especially in plant effluents, is described, which comprises continuously taking a constant part stream from the effluent stream, hydrolyzing the part stream under alkaline conditions with an alkali solution added at a constant rate under constant conditions, subjecting it to partial vaporization conditions, condensing the resulting vapor stream by cooling, determining the electrical conductivity in the condensate continuously in a flow cell and converting the measured values obtained into the desired concentration values by reference to a calibration curve or known equations.

Abstract: A method and an agent for the determination of maleimide groups, comprising reacting a sample containing maleimide groups with a reagent containing thiol groups and then with a chromogen or fluorogen which reacts with thiol groups, and measuring the change in intensity.