Abstract: A method of pretreating aqueous chemical oxygen demand (COD) samples to remove the risk of potential chloride ion interference. The method comprises acidifying an aqueous COD test sample, and thereafter passing the acidified sample through a source of pentavalent bismuth (Bi.sup.5+) such as sodium bismuthate.

Abstract: An improved measurement cell and circuit for measuring the electrical characteristics of a liquid sample during exposure to radiation includes a glass cell formed of a main tube extending generally parallel to an elongated lamp emitting the radiation, and a pair of electrodes disposed axially within the sample tube. In the preferred embodiment, the ends of the cell are formed of glass twinbore tubing fused to the glass main tube, the bores retaining ends of the electrodes. Inlet and outlet tubes and a temperature sensing well may also be fused to the main tube. In an implementation for measurement of TOC in water by oxidation to CO.sub.2, the source comprises a low pressure mercury vapor lamp, and the electrodes are formed of solid Ti with catalytic TiO.sub.2 surfaces.

Abstract: A method of pretreating aqueous chemical oxygen demand (COD) samples to remove the risk of potential chloride ion interference. The method comprises acidifying an aqueous COD test sample, and thereafter passing the acidified sample through a source of pentavalent bismuth (Bi.sup.5+) such as sodium bismuthate.

Abstract: A kit and method are provided for determining the suitability of the level of organic material in an aquarium. A test sample of water is removed from an aquarium into a test sample container. The pH of the test sample can be lowered and then a quantity of potassium permanganate is added and the test sample is permitted to sit. A control sample of distilled water mixed with an equal amount of potassium permanganate is also prepared in a second container. After a period of time passes, the color of the test sample is compared to the color of the control sample. If the test sample is significantly lighter, additional potassium permanganate is added to the test sample and this procedure is repeated until the test sample achieves the color of the control solution. The amount of potassium permanganate needed to turn the test sample to the color of the control sample is directly proportional to the amount of organic material in the tank.

Abstract: Apparatus and method for measuring tissue oxygenation using oxygen dependent quenching phosphorescence. The apparatus comprises a phosphorescent probe applied to the surface of the skin; an oxygen impermeable film placed over the probe and the apparatus; a light excitation means for exciting the probe; a heating element for heating the probe; and an analyzer circuit for analyzing the output.

Abstract: An oxygen electrode comprising a plastic sheet, two or three electrode patterns formed on the plastic sheet, a paraffin layer formed on the peripheral portion of the plastic sheet for delineating a sensitive area, a carrier sheet impregnated with an electrolyte and placed on the central portion or the sensitive area of the plastic sheet, and a gas permeable membrane covering the carrier sheet and the paraffin layer. A biosensor may be also provided by further providing a microorganism or enzyme-immobilized layer on the gas permeable membrane of the above oxygen electrode.

Abstract: A dye couple compound is provided for use in a test device containing a reagent system for detecting the presence or quantity of an analyte in a sample. The reagent system comprises one or more enzymes which, in the presence of the analyte, produce an oxidizing agent in quantities indicative of the quantity of analyte in the sample. The compound of choice is meta[3-methyl 2-benzothiazolinone hydrozone]N-sulfonyl benzenesulfonate monosodium.

Abstract: A method of analyzing aqueous samples for Chemical Oxygen Demand (COD) which involves using an analysis reagent comprised of a mixture of stabilized Manganese III ion and an inorganic non-oxidizing acid such as sulfuric or phosphoric acid. Manganese III ion (or manganosulfuric acid complex) is purple, and, as it is reduced to Manganese II ion, the purple color decreases to colorless. Manganese III Chemical Oxygen Demand test is preferred over the presently available chromium reagent test because Chromium VI ion is a known carcinogen, the reagent is photosensitive and a silver catalyst is required. Manganese III is not carcinogenic or photosensitive and does not require a silver catalyst.

Abstract: An efficient method for the microfabrication of electronic devices which have been adapted for the analyses of biologically significant analyte species is described. The techniques of the present invention allow for close control over the dimensional features of the various components and layers established on a suitable substrate. Such control extends to those parts of the devices which incorporate the biological components which enable these devices to function as biological sensors. The materials and methods disclosed herein thus provide an effective means for the mass production of uniform wholly microfabricated biosensors. Various embodiments of the devices themselves are described herein which are especially suited for real time analyses of biological samples in a clinical setting. In particular, the present invention describes assays which can be performed using certain ligand/ligand receptor-based biosensor embodiments.

Abstract: An automated method and apparatus for determining the dissolved oxygen (DO) content and the biochemical oxygen demand (BOD) of multiple test samples includes a sample set containing several test sample containers, a robotic arm capable of motion toward the sample set, DO probes releasibly attached to the robotic arm, and a programmable computer interfaced with the robotic arm and controlling the robotic arm. To measure the DO of test samples within the test sample containers, DO probes (which are connected to respective DO meters) are positioned adjacent a set of test sample containers and inserted within, the DO meters determine the DO within the test sample containers, the DO values are recorded by use of a programmable computer, and the DO probes are then removed from the set of test sample containers.

Abstract: The biochemical oxygen demand (BOD) of aqueous liquids containing organic matter is determined. A microorganism culture is aerated to exhaust the organic matter available to the microorganisms. An aqueous liquid test sample containing organic matter is added to the exhausted culture to measure the amount of oxygen consumed by the microorganisms. The determination of biochemical oxygen demand (BOD) of the sample is determined in as little as 20 minutes. An apparatus is provided for determining BOD comprising a magnetic stirrer, an aerating instrument, a dissolved oxygen/temperature sensor, tubing pumps and a quick biochemical oxygen demand (QBOD) bottle. The BOD may be automatically calculated using the apparatus.

Abstract: The present invention relates to a BOD analyzer comprising a microbe sensor containing an oxygen electrode and a microbe membrane. The microbe membrane is made by immobilizing microorganisms belonging to the genus Klebsiella in membrane. Specifically, the present invention relates to a BOD analyzer comprising flow cell equipped with a microbe sensor containing an oxygen electrode and a microbe membrane; and a liquid passage which is connected with the entrance of the flow cell and which is equipped with an outlet. The microbe membrane is made by immobilizing microorganisms belonging to Klebsiella oxytoca 12092 strain in a porous hydrophilic membrane having an average pore size of 0.65-3 .mu.m in diameter by using at least one gelating agent selected from the group consisting of alginic acid or salts thereof, agar, gellan gum, xanthane gum, gelatine, carageenan, locust bean gum, methylcellulose, pectin, and pullulan.

Abstract: To analyze the oxidizable substances, for example the chemical oxygen demand (COD), contained in an aqueous sample liquid, for example sewage water, the aqueous sample liquid is diluted with dilution water and fed into a reaction container where it is mixed with ozone from an ozone generating device. After passing through a second reaction container, for example a tubular reactor, the sample liquid reaches an ozonometer appliance. Ozone being added continuously, the ratio of sample liquid to dilution water of the mixture is regulated in such a manner that the residual ozone content measured by the ozonometer appliance remains constant at a predetermined level. The ratio of sample liquid to dilution water of the mixture required to maintain the reading on the ozonometer at the predetermined level is used to determine oxidizable substances contained in the water, in particular COD.

Abstract: A pressure/vacuum method and instrument for detecting biological activities in blood culture vials, that is non-invasive, does not require chemical sensors, does not require high-brightness short-wavelength light sources, is safe against eventual extreme high pressure values, and is head-space-temperature compensated. A culture medium and blood specimen are introduced into a sealable glass vial. The normally incompressible fluid suspension is made compressible through the use of a partially inflated gas bag submerged within the medium. The changes in fluid position that result from bacterial growth related pressure changes within the vial head space are measured to detect biological activities.

Abstract: A fouling monitor and method for sensing fouling in commercial waters and for differentiating between microbiological fouling and chemical fouling, which includes a dissolved oxygen probe disposed in a slip stream of water and means for providing an abundance of oxygen and nutrient to the microbial activity whereby a decrease in dissolved oxygen level is sensed due to the increased respiration of the microbes when microbiological fouling occurs. A polyester screen is mounted over the sensing end of the dissolved oxygen probe to promote microbiological fouling by providing a means for engaging the microbes and to enhance differentiation between the biological component and the non-viable/chemical component.

Abstract: A fouling monitor and method for sensing fouling in commercial waters and for differentiating between microbiological fouling and chemical fouling, which includes a dissolved oxygen probe disposed in a slip stream of water and means for providing an abundance of oxygen and nutrient to the microbial activity whereby a decrease in dissolved oxygen level is sensed due to the increased respiration of the microbes when microbiological fouling occurs. A polyester screen is mounted over the sensing end of the dissolved oxygen probe to promote microbiological fouling by providing a means for engaging the microbes and to enhance differentiation between the biological component and the non-viable/chemical component.

Abstract: A toxic substance-detecting device detects toxic substances in water by use of a microorganism sensor to ascertain the safety of affluents flowing into sewage-treating processes, environmental waters such as rivers, and waters flowing into water purification plants and a water quality-monitoring system employing a detecting device. The device includes a fixed micro-organism membrane and apparatus for circulating a buffer solution of micro-organism substrate and nutrient to one side of the membranne and solutions of water to be examined, standard and cleaning water to the other side.

Abstract: Apparatus and methods for the measurement of total organic carbon and total inorganic and organic content of water are described. A novel combination of an acidification module, and inorganic carbon removal module based on a carbon dioxide selective gas permeable membrane, and oxidation reaction system which incorporates in-situ generation of oxidizing agents, coupled with catalyzed photo-oxidation of organic compounds to form carbon dioxide; and a high sensitivity, conductometric detector employing a carbon dioxide selective gas permeable membrane permits on-line measurement of the total organic carbon content of water streams.

Abstract: Various embodiments of respirometers are used to determine the biochemical oxygen demand (BOD) of samples. The respirometer includes chamber walls formed from a membrane permeable to oxygen, thereby allowing reoxidation of the contained sample. In order to ensure reliability in the computed BOD values, the respirometer preferably incorporates a framed structure, and the fluid containing chamber has a predetermined volume and repeatable configuration. The present invention is particularly directed to an improved method of determining oxygen demand for respiring liquid samples, utilizing the dissolved oxygen data and the rate of oxygen transfer through the respirometer walls.

Abstract: In order to simplify the operation for determination of the acid-base status of blood, composed of the values for pH, pCO.sub.2 and the base excess BE, the base excess BE is determined through measurement of the pH-value at a pCO.sub.2 of about 0 mn Hg. The pH-values may be determined photometrically, in which case the indicator solution for measuring the actual blood-pH is an aqueous solution of 40 micromol/l bromthymol blue plus 0.2 g/l sodium dodecylsulfate plus 1% ethanol; and for measurement of the base excess BE is an aqueous solution of 65 micro mol/l naphtholphthalein plus 0.2 g/l sodium dodecylsulfate plus 15% dimethylsulfoxide, which are measured at a wavelength of 635 nm. If desired, one may use a single solution for measuring both actual blood-pH as well as the base excess BE, composed of 16 micromol/l bromthymol blue plus 34 micromol/l naphtholphthalein plus 0.15 g/l sodium dodecylsulfate, which is measured at 615 nm wavelength.

Abstract: Different embodiments of a respirometer are described which are used to determine the BOD of less dilute samples that can be permitted in the standard BOD test procedure. Different embodiments of the respirometer are formed of a chamber, walls of which are formed from a membrane permeable to oxygen to permit reoxygenation of the contained sample in the respirometer. In order to ensure reliability in the computed value of BOD, the chamber of the respirometer incorporates a framed structure.

Abstract: Method and device for determining the respiration rate of a respiring material such as active sludge in a continuous process flow before and after holding thereof in a respiration chamber. The oxygen content in the continuous process current is done at a single measurement point. This is done by reversing the incoming and outgoing current of the respiration chamber. Preferably the process flow consists of a mixture of respiring material and waste water to be biologically purified.

Abstract: A process and apparatus for measuring the degree of pollution, the degradableness, and the level of toxicity of aqueous liquids, for example, effluent. A partial stream is withdrawn from the liquid undergoing examination and diluted with biologically neutral water. The diluted partial stream is oxygenated and continuously flows through a biological bath in a reaction vessel having a constant living mass. The dilution of the partial stream is regulated in such a manner through measurement of the oxygen content upstream and downstream of the reaction vessel, that with constant volume flow through the reaction vessel, the difference between the measurement values obtained remains essentially constant at a predetermined value, so that the amount of dilution serves for the indication of the level of pollution. Additional reaction vessels connected in parallel or in series with the first reaction vessel and having associated oxygen electrodes allows measurement of the toxicity and degradableness of the pollution.

Abstract: A microwave-based apparatus for rapid digestion of a sampel by a Kjeldahl method is provided which includes a reaction vessel surrounded by an insulator in the form of, for example, a cup. The reaction vessel is disposed in the internal chamber of a microwave system, which includes a wall having an aperture. A connector tube is slidably disposed in the aperture, wherein one end of the tube is connected to the mouth of the reaction vessel, and the other end is connected to a suction device external to the chamber. A biasing element is provided outside the chamber to assist in joining the slidable connector tube to the mouth of the vessel, yet enabling removal of the vessel from the chamber without detachment of the biasing element.

Abstract: A respirometer for determining oxygen demand of respiring liquid is described. The respirometer has a chamber to be filled with the liquid. The chamber includes a base plate, a cover plate, a plurality of supports extending between the base plate and the cover plate, and a side wall made of an oxygen permeable membrane. The cover plate has an opening therein which is capable of supporting a dissolved oxygen probe. The opening also acts as an inlet and outlet to the chamber. A rotor is provided in the chamber for stirring the liquid.

Abstract: An improved digestion chamber (10) is provided for use in a carbon analysis system. A catalyst (16), selected from the platinum metals group consisting of platinum, rhodium, palladium, osmium, iridium and ruthenium, provides an oxidizing surface for the sample being analyzed. The oxidant (26) is preferably persulfate, which may be stored in a generally stable solution until needed for sample oxidation. The catalyst (16) may be provided as a digestion chamber wire insert, such as a rod or as a plating on the chamber walls, enabling an increased variety of materials to be used for the vessel. In a preferred embodiment of the digestion chamber, polytetrafluoroethylene is used to reduce the background carbon which must be corrected in the analysis.

Abstract: A system for controlling a process utilizing filamentous microorganisms is disclosed. The amount of the microorganisms in a medium for growing the filamentous microorganisms is measured, and the control factors associated with the growth of the microorganisms in the medium are controlled on the basis of the measurement of the amount of microorganisms. In the process of measuring the amount of microorganisms, an optical image of a specimen of the medium is formed and scanned two-dimensionally to produce a series of brightness signals corresponding to the brightness distribution of the optical image. The level of the brightness signal is used to determine the amount of the microorganisms contained in the medium.

Abstract: A submersible recording respirometer includes an oxygen analyzer which measures the concentration of oxygen absorbed by a wastewater sample contained in an aeration chamber. The aeration chamber forms part of a housing which is submerged in the main body of wastewater and the aeration chamber is periodically drained, washed with fresh water and refilled with another wastewater sample. This cycle is accomplished automatically under the direction of a microprocessor-based control circuit which generates signals to a chart recorder that provides a hard copy of the measurement results.

Abstract: Total organic carbon can be determined for each one of a plurality of discrete aqueous samples containing halide ion by means of an apparatus comprising a reactor (13), and a pump (12) and flowline (11) for introducing a continuous flow into the reactor (13) of a solution that contains an oxidizing agent and mercuric monohalide ion without forming an insoluble precipitate. The solution to be introduced into the reactor (13) is prepared by mixing the oxidizing agent with a solution containing mercuric monohalide ion; and the solution containing mercuric monohalide ion is formed by adding a quantity of mercuric halide and a quantity of mercuric nitrate to an aqueous solution containing nitric acid, where the molar concentration of the mercuric halide is at least equal to the molar concentration of the mercuric nitrate.

Abstract: Total organic carbon in an aqueous sample containing halide ion is determined by preparing an aqueous solution containing an oxidizing agent and mercuric monohalide ion without forming an insoluble precipitate, introducing the sample into the solution so formed, irradiating the solution and sample with ultraviolet energy to oxidize organic matter in the sample to produce carbon dioxide, sparging the carbon dioxide so produced from the solution, and measuring total carbon in the carbon dioxide. The aqueous solution is prepared by mixing the oxidizing agent with a solution containing mercuric monohalide ion, which is formed by adding a quantity of mercuric halide and a quantity of mercuric nitrate to an aqueous solution containing nitric acid, where the molar concentration of the mercuric halide is at least equal to the molar concentration of the mercuric nitrate.

Abstract: Method and an apparatus for determining the chemical oxygen demand (COD) of waters by a photochemically accelerated oxidation with oxygen. This method, if desired, may be combined with the step of measuring the contents which the waters have in organically bound carbon.

Abstract: For the quantitative determination of the total oxygen demand of water containing oxidizable matter, the water is continuously evaporated at about 900.degree. C. in the presence of varying amounts l.sub.1, . . . , l.sub.n of oxygen-containing gas added per unit of steam at continuously repeated intervals. The oxygen-containing gas should not exceed 1 to 5% by volume, calculated on the amount of steam produced during each interval. The residual oxygen concentrations S.sub.1, . . . , S.sub.n in the steam gas/mixture are measured for the different amounts of oxygen-containing gas added and the oxygen demand is calculated from the residual concentrations and the added amounts of the oxygen-containing gas.

Abstract: In the determination of the quantity of carbon present in water in the form of organic compounds the carbon-containing water is first evaporated in the presence of oxygen at a temperature of about 900.degree. C. Care must be taken that the oxygen does not exceed 1 to 5 volume %, calculated on the quantity of steam. Then the CO.sub.2 content is measured with a CO.sub.2 analyzer. In a second step the carbon-containing water is measured without oxygen under identical conditions. The quantity of carbon present in water in the form of organic compounds is determined from the measured CO.sub.2 concentrations.

Abstract: Analysis of and apparatus for studying simple or complex agglutination reactions, such as for blood analysis and in particular blood groupings in which the specimen is mixed with at least one reagent in a vessel of predetermined shape and this mixture is incubated and thereafter centrifuged in this vessel. The nature of the reaction, the operations performed on the mixture and the shape of the vessel are such as to provide at cessation of the centrifuging the accumulation of the agglutinated particles at a particular location in the vessel. Following a waiting period in which the mixture is given the opportunity to partly or substantially entirely move under the influence of gravity away from said location, the path of said movement is observed by an optical arrangement which enables determination of the nature of the reaction, i.e. the presence or absence of agglutinated or non-agglutinated elements is observed after a time interval sufficient to permit their separation.