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The principle is based on the conversion of the methanol present in a test portion to formaldehyde by oxidation with a solution of potassium permanganate in phosphoric acid. Reaction of the formaldehyde formed with Schiff reagent. Visual comparison of the colour obtained with the colours of standard colorimetric solutions containing known quantities of formaldehyde. - International Standards ISO…

The principle is based on distillation of a test portion in the presence of water, addition to the distillate of a saturated sodium chloride solution and measurement of the volume of insoluble hydrocarbons. A Hempel fractionating column with Liebig condenser is used for the distillation. - International Standards ISO 1388/1 to ISO 1377/12 cancel and replace ISO Recommendation R 1388-1970 of which…

The document also specifies the methods to be used for the determination of density at 20 °C, for the determination of dry residue after evaporation on a water bath, for the determination of water content, and for the measurement of colour. - International Standards ISO 1388/1 to 1388/12 cancel and replace ISO Recommendation R 1388-1970 of which they constitute a technical revision.

The method is applicable to products having acidities equal to or greater than 0.0008 % (m/m). The principle consists in the dilution of a test portion with carbon dioxide-free water, checking whether the test solution is alkaline or acid to phenolphthalein, and, if appropriate, determination of the acidity by titration with standard volumetric sodium hydroxide solution. The acidity is expressed…

The general method is applicable to phosphoric acid not containing polyphosphoric acids and to products having a calcium content equal to or greater than 0.020 % (m/m). In special cases a preliminary hydrolysis of polyphosphoric acids is carried out by prolonged boiling in the presence of hydrochloric acid. Precipitation of calcium as calcium oxalate at pH 4 0.3, filtration of the precipitate,…

The procedure consists in addition of water to a test portion, under specified conditions, and followed by examination vertically for any opalescence or turbidity against a black background with side illumination. International Standards ISO 756/1, ISO 756/2 ans ISO 756/3 cancel and replace ISO Recommendation R 756-1968 of which they constitute a technical revision.

Applicable to products having Ca contents equal to or more than 50 mg/kg. The presence of soluble SiO2 up to 5 g/ml in the test solution does not interfere. Hydrolysis by boiling a test portion in hydrochloric acid medium. Addition of sodium ions, until a constant concentration is obtained, to stabilize the promotion and emission of Ca; addition of lanthanum chloride to increase the sensitivity…

A test solution is treated with an excess of acidified potassium bromide-bromate solution in the presence of mercury(II) sulphate. After addition of potassium iodide solution the liberated iodine is titrated with standard volumetric sodium thiosulphate solution.

La présente Norme internationale spécifie une méthode par spectrométrie d'absorption atomique dans la flamme, pour le dosage du calcium dans les phosphates condensés à usage industriel, y compris les industries alimentaires. La méthode est applicable aux produits dont la teneur en calcium est supérieure ou égale à 50 mg/kg. La présence de silice (SiO2) soluble jusqu'à 5 µg/ml de…