Rechercher

Specifies a method for the comparison of the colour of a test portion against the colour of colorimetric standard colour matching solutions. The colour of cresols present in the test portion is liable to darken on keeping and on exposure to ligth. ISO 1897/7 replaces ISO Recommendation R 1909-1971.

This method is the best available at the present time. It was primarily intended for samples containing 40 % (m/m) or more but has been extended to lower ranges. The principle is based on dehydration of a quantity of the test sample. Formation of a complex between o-cresol and cineole (having a crystallizing point not lower than 1,2 °C) by addition of excess cineole to a test portion of the…

The method is applicable to a product containing 35 % (m/m) to 60 % (m/m) of m-cresol, not more than 5 % (m/m) of phenol, and not more than 35 % (m/m) of o-cresol. The principle is based on dehydration of a quantity of the test sample. Formation of a complex between m-cresol and urea by addition of excess urea to a test portion of the dehydrated sample. Determination of the crystallizing point of…

1. SCOPE 1.1 This Standard covers the requirements for the safe installation, operation and maintenance of woodworking machinery, including cooperage and veneering operations and the finishing of wood products. 1.2 This Standard does not apply to logging and primary milling operations.

The principle is based on the dissolution, in hot hydrochloric acid, of the residue from the determination of the ash of a test portion (see ISO 1389/8). Reduction, by hydroxylammonium chloride, of the iron(III) contained in the solution thus obtained, formation of the coloured complex iron(II)-2,2'bipyridyl in a buffered medium. Photometric measurement of the coloured complex at a…

The principle consists in treatment of a test portion in acid solution with excess standard volumetric potassium bromide-potassium bromate solution, addition of potassium iodide solution and titration of the liberated iodine with a standard volumetric solution of sodium thiosulphate. - Replaces ISO Recommendation R 761-1968.

Conversion of the iron in a test portion to iron(III) sulphate by evaporation to dryness in the presence of sulphuric acid. Dissolution in nitrid acid, reduction of the trivalent iron in the solution thus obtained by hydroxylammonium chloride. Photometric measurement of the coloured complex iron(II)-2,2' -dipyridyl. Applicable to products having Fe contents in the range 0,1 to 2 mg/kg.

With respect to the free acidity, applicable to products having contents, expressed as H2 SiF6 , equal to or more than 0,1 % (m/m). First, determination of the free acid contents by titration of an ice-cooled test portion with a standard volumetric sodium hydroxide solution in the presence of potassium nitrate and using bromothymol blue as indicator, then, followed by titration at near boiling…