Abstract: A method and composition for detecting the presence of an alkali metal on the surface of a body such as a metal plate, tank, pipe or the like is provided. The method comprises contacting the surface with a thin film of a liquid composition comprising a light-colored pigment, an acid-base indicator, and a nonionic wetting agent dispersed in a liquid carrier comprising a minor amount of water and a major amount of an organic solvent selected from the group consisting of the lower aliphatic alcohols, ketones and ethers. Any alkali metal present on the surface in elemental form or as an alkali metal hydroxide or alkali metal carbonate will react with the acid-base indicator to produce a contrasting color change in the thin film, which is readily discernible by visual observation or automatic techniques.

Abstract: This application relates to thyroxine (T.sub.4) immunoassay procedures and, in particular, to the preparation of a novel filter-paper test substrate and a novel standard reagent used in preparation of the test substrate. The standard reagent used in preparation of the test substrate is prepared from commercially available materials and does not require the use of a human serum component.

Abstract: A test tube having an inner tube that allows one to insert a bar to create a dark background is described. This system is actually an ordinary or screw-capped test tube with a smaller sized test tube inverted and fused to the bottom. The design permits a thin layer of any agar medium to solidify around the inside edge of the larger tube. The colonies developed in the agar can then be easily counted by creating a dark background by inserting a dark colored rod through the opening of the inner tube.Alternatively, a permanently dark-colored inner tube can be inverted and fused to the bottom of the outer tube. In this case, it is not necessary to insert a rod to create a dark background and the enumeration of microbial colonies is as easy as the method described above.

Abstract: A method for detecting the presence in water of substances which are rapidly oxidized by ozone with the emission of quanta of visible light, which method comprises contacting the water with ozone and detecting the light quanta emitted.

Abstract: A device for monitoring ethylene oxide sterilization processes comprising a wick means impregnated with an ethylene oxide responsive chemical compound, a pH sensitive dye and a quantifier mounted on a backing strip and sealed with a cover strip to form an envelope having one edge at which the wick means is exposed. The device is responsive to time, temperature and relative humidity as well as ethylene oxide concentration.

Abstract: A simple, sensitive, reliable and safe method and device for detecting pregnancy. The test involves concentration in the presence of polyvinylpyrrolidone by ultrafiltration of a sample of urine or serum from a subject; followed by determining the presence of human chorionic gonadotropin or of its .beta.-subunit in the concentrated sample.

Abstract: Chromic acid anodized aluminum is placed in an enclosed container and covered with an aqueous alkali metal hydroxide solution. The rate of formation of hydrogen gas generated by the chemical interaction of the aluminum and the hydroxide determines corrosion resistance of the anodic film.

Abstract: A method and apparatus for determining in a laboratory the thermal cracking behavior of hydrocarbon feedstocks which are to be used in industrial cracking furnaces. The apparatus used includes an evaporation assembly and a cracking furnace assembly. A sample of hydrocarbon feedstock is first vaporized, then thermally cracked, and the cracked products are then fed to gas chromatography analytical equipment for analysis.

Abstract: A diagnostic composition containing as a chromogen a diamino-biphenyl derivative in which at least one of the hydrogen atoms in the amino groups thereof is replaced by a lower alkyl group by reaction with an alkylating agent. The diagnosing instrument is prepared by impregnating a bibulous, porous support in a solution comprising the diagnostic composition and optionally a saccharide oxidase, peroxidase and a guaiac, and, if necessary, a buffer, a surfactant, a background adjusting dye and/or an agent for increasing the viscosity of the composition. This diagnosing instrument can be handled in a simple and convenient way and is used to identify semi-quantitatively a saccharide in body fluids or excrements of humans or animals with reliability.

Abstract: An improved analytical element for the detection of a predetermined analyte in an aqueous liquid under highly alkaline conditions is disclosed. The element features a stable, alkaline-providing composition.Preferably, the analytical element is a multi-zone element. The element is particularly useful in total protein analysis and, when so used, an improved biuret reagent composition for use therein is also provided. Methods of using the aforementioned analytical and biuret reagent composition are also disclosed.

Abstract: A halogen detector is disclosed herein in which the active alkali metal compound is independently heated thereby permitting the sensor to discriminate between halogen compounds of different thermal stabilities. Certain lesser stable halogen compounds such as Freon 22 and chloroform can be distinguished from more stable halogen compounds such as Freon 12 when such halogen compounds are present in air.

Abstract: Curvette of generally circular form having apertures adjacent the outer periphery and having a plurality of compartment elements formed of an optically-clear plastic snugly locked in the apertures.

Abstract: Disclosed is a technique for accelerating the Hantzsch reaction, for the clinical determination of triglyceride, so as to permit the reaction to be analytically complete within 15 minutes at 37.degree. C. As is known, in this Hantzsch reaction, one mole of aldehyde is reacted in a solution predominantly containing alcohol and water with two moles of a betadicarbonyl compound in the presence of ammonia to yield, as a colored derivative, a lutidine. In the disclosed technique, the solution also contains an organic accelerator compound. This compound is capable of forming a clear solution with the mixture of components of the reaction solution and is further characterized as having an aprotic internal dipole such that said compound has a distinct center which is electron rich and a center which is electron deficient.

Abstract: A wide range combustion mixture air/fuel ratio sensor in which an electrochemical cell supplies hydrogen gas to a palladium sensor element at a rate regulated by the output of a Wheatstone bridge circuit incorporating the sensor element. This generated hydrogen gas combines with any oxygen present in the exhaust gas through catalytic action and also maintains the level of absorbed hydrogen, and therefore the electrical resistance of the palladium sensor element, at a preselected value. The magnitude of the current applied to the electrochemical cell necessary to maintain this balance is a measure of the combustion mixture air/fuel ratio.

Abstract: The invention provides a combustible gas detector in which a heatable wire filament embedded in a pellet comprising oxidation catalyst material exhibits a change in resistance occasioned by the change in its temperature which occurs due to the oxidation of a combustible gas passing over it.The pellet is provided with an outer layer of inert non-catalytic material which tends to prevent non-volatile residues from reaching catalytically active regions of the detector.

Abstract: Improved analysis of sulfur concentration in carbonaceous sample uses carbon dioxide produced by the sample as an internal monitor of sample density reflected in the derived sulfur concentration.

Abstract: Apparatus for the determination of the oxidative stability of polymers exhibiting viscous or visco-elastic flow at the temperature of the determination is disclosed. The apparatus comprises a mixing head having means to subject polymer to shear, means to measure the oxygen content of gas, means to circulate the gas from the mixing means to the analyzing means and back to the mixing head and pressure control means to control the pressure of the gas at atmospheric pressure without extraneous dilution. In a preferred embodiment the pressure control means includes an elongated tube having a ratio of length to diameter of at least 800. A method for determining the oxidative stability of polymer under shear conditions is also disclosed. The apparatus and process may be used for the determination of the oxidative stability of, for example, elastomeric and thermoplastic polymers under conditions resembling the conditions under which such polymers are fabricated into articles.

Abstract: The invention pertains to "wet chemistry" analytical devices for pollutant gases in air. Numerous improvements are provided including a thermo-electric heating/cooling device which uses the atmosphere as a heat sump. Critical flow means to maintain constant pressure throughout the system is also provided.

Abstract: Calibration apparatus is described for use in a calibratable analytical system wherein a continuously flowing liquid sample, either alone or in admixture with other liquids, is normally caused to contact a sensor. The novel calibration apparatus enables diversion of said continuously flowing sample out of contact with the sensor and alternate contact of a calibration reference liquid or other calibration sample with the sensor. The calibration apparatus of the present invention is particularly useful in a system for analytical monitoring of a continuously flowing liquid blood sample obtained through a double lumen cannula inserted into a blood vessel of a human or animal subject. This apparatus permits the analytical system to be calibrated without the necessity of removing any portion of the cannula from the subject thereby avoiding the risk of loss of sterility inherent in such removal.

Abstract: Reagent and reagent mixtures useful for detecting and measuring total bilirubin concentrations in biological liquids such as serum and methods of assaying biological liquids using such reagents are disclosed.