Abstract: There is disclosed a method for quantitatively determining protein, comprising the steps of:(a) providing a sample of the protein in an aqueous medium;(b) providing an aqueous medium having a pH in excess of 12 and comprising(i) a cupric salt and a pyridyl-azo dye; or(ii) a preformed cupric-pyridylazo dye complex;(c) combining the aqueous mediums of a) and b) thereby providing a color having an intensity which is inversely proportional to the amount of unreacted dye present in the combined mediums; and(d) determining the quantity of protein present in the sample colorimetrically.The method can be used with a multilayer dry analytical element.

Abstract: The invention concerns a method and an equipment for the simulated distillation, by means of gas chromatography, of petroleum products, capable of characterizing also high boiling products, exceeding C55, over 600.degree. C. TBP. A chromatograph is used with a capillary column having a length less than or equal to 10 m, containing an immobilized non polar polydimethylsilicon gum stationary phase with a film thickness less than or equal to 0.2 .mu.m. The sample is introduced through a non vaporizing direct cold on-column injection and the eluted sample is detected by means of a FID detector. The column oven is operated in temperature programming conditions up to temperatures exceeding 400.degree. (up to 430.degree.-450.degree. C.).

Abstract: A mixture of fluorescently-excitable amino acid derivatives suitable for use in quantitative amino acid analysis is provided in which primary amino acids are present as derivatives of a first reagent and secondary amino acids are present as derivatives of a second different reagent. The process for preparing the mixture comprises the steps of derivatization of the primary amino acids of an amino acid sample with ortho-phthalaldehyde (OPA) and of derivatization of the secondary amino acids of the sample with fluorenylmethylchloroformate (FMOC) in the presence of acetonitrile. The mixture can be obtained automatically and is highly suitable for fast analysis by reversed-phase liquid chromatography.

Abstract: A method of continuous rapid determination of the J-value during the oxidative coupling reaction of phenols to form polyphenylene ethers. Solution of a defined temperature is withdrawn from the reaction mixture, the viscosity of the solution is measured in a Couette viscometer, and the J-value is determined using a calibration curve or mathematical means.

Abstract: A test tube for combustible gases is intended to be provided with protective devices, so that, in proving the presence of combustible gases, it cannot become an ignition source. To that end, a flame arrester is arranged in front of and/or behind the test material.

Abstract: A method for the quantitative determination of lithium in a liquid test sample employing turbidimetric or nephelometric techniques to measure the maximum rate of change in the optical density of a reaction mixture containing precipitated lithium. The lithium is precipitated by a lithium precipitating reagent to result in dispersed, suspended particles, and the maximum rate of change in optical density determined to provide a linear dose response which can be quantitatively correlated to the amount of lithium present in the test sample.

Abstract: A method for controlling a liquid volume flowing onto a reactive surface which includes a sample application port, two systems of capillary channels, a reaction chamber, and an overflow chamber. The liquid sample to be analyzed is applied to the sample application port which gives the liquid entry to a capillary channel leading to the reaction chamber which contains a material capable of detecting the component of interest in the liquid. When the reaction chamber is filled, the remaining liquid will flow through another capillary channel to an overflow chamber. The capillary channel leading to the overflow chamber is controlled so that liquid cannot flow back into the reaction chamber.

Abstract: A vapor stripping cell for the transfer of volatile organic substances from either an aqueous phase of a solids sample dispersed in an aqueous phase to a suitable vapor trapping medium for subsequent gas chromatographic analysis. It comprises a bottle-like cell into which extends a tube terminating adjacent the perimetrical portion of the bottom of said cell for introducing organic substance to be tested. A drive is provided for oscillating the bottom of said cell while maintaining the top substantially stationary to spread said substances substantially uniformly on the inner surface of said cell.