Rechercher

The principle is based on the conversion of methanol present in a test portion to formaldehyde by oxidation. The oxidation is carried out with a solution of potassium permanganate in phosphoric acid. Reaction of the formaldehyde formed with chromotropic acid (4,5-dihydroxynaphthalene-2,7-disulphonic acid). Photometric measurement of the violet coloration obtained at a wavelength of about 570 nm…

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.

This second edition cancels and replaces the first edition (i.e. ISO 621-1975). Specifies principle, reagents, apparatus, sample, procedure and expression of results.

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,…

Method I is applicable to manganese ores having vanadium contents greater than 0.05 % (m/m), method II is applicable to manganese ores having vanadium contents less than 0.05 % (m/m). This second edition cancels and replaces the first edition (i.e. ISO 553-1975). Should be read in conjunction with ISO 4297.

This second edition cancels and replaces the first edition (i.e. ISO 548-1975). Should be read in conjunction with ISO 4297. Specifies principle, reagents, apparatus, sample, procedure and expression of results.

The method is applicable to products having zinc contents between 0,002 and 6 % (m/m). Specifies principle, reagents, apparatus, sampling, procedure, expression of results and test report.