Hydrochloric acid for industrial use — Determination of sulphated ash — Gravimetric method
The principle of the method consists in evaporation of a test portion; conversion of the salts in sulphates by treatment with sulphuric acid. Ignition in an electric furnace, maintained at (800 +- 50) °C, and weighing. Replaces ISO Recommendation R 907-1968.
Sodium tripolyphosphate for industrial use — Determination of matter insoluble in water
Dissolution of the test portion in water by boiling. Separation of any matter undissoved by filtration under vacuum. Drying in an oven, controlled at a temperature of (110 5) 0C, and weighing, Replaces ISO Recommendation R 850/1968.
Sodium tripolyphosphate for industrial use — Measurement of pH — Potentiometric method
Measurement of the pH of a 10 g/l solution. Uses a pH meter fitted with a glass measuring electrode and a calomel reference electrode. Sensitivity 0.05 pH unit.
Sodium tripolyphosphate and sodium pyrophosphate for industrial use — Determination of loss on ignit...
Weighing of a test portion into a porcelain crucible and ignition in a muffle furnace controlled at a temperature of (550 +/- 25) 0C to a constant mass. Replaces ISO Recommendation R 853/1965.
Phosphoric acid for industrial use (including foodstuffs) — Determination of chloride content — Pote...
Applicable to products having Cl- contents, expressed as chlorine, equal to or more than 0.001 % (m/m). The lower limit can be extended downwards by using weaker standard reference and volumetric solutions. Describes potentiometric titration of the ions with silver nitrate solution in a nitric acid-acetone-water medium using a silver measurement electrode and a calomel reference electrode.
Phosphoric acid for industrial use (including foodstuffs) — Determination of oxides of nitrogen cont...
Applicable to products having a content, expressed as N, equal to or more than 0.2 mg/kg. Consists in oxidation of nitrous nitrogen to nitric nitrogen by potassium permanganate and reaction of nitrogen(V) with 3,4-xylenol under specified conditions to form a nitrate derivative. Subsequent destillation of the nitrate derivative and absorption in sodium hydroxide solution. Spectrophotometric…
Phosphoric acid for industrial use (including foodstuffs) — Determination of total phosphorus (V) ox...
Applicable to products whether or not they are homogeneous and whether or not they contain polyphosphoric acids. Specifies preliminary hydrolysis of the polyphosphoric acids by boiling in the presence of hydrochloric acid. The precipitation of the phosphoric acid is carried out in the form of quinoline phosphomolybdate in the presence of acetone. Filtration by a filter crucible, washing, drying…
Sodium hydroxide for industrial use — Determination of calcium and magnesium contents — Flame atomic...
Applicable to products having contents of more than 2.5 mg Ca/kg and 0.5 mg Mg/kg if an acetylene-air flame is used or 0.6 mg Ca/kg and 1.0 mg Mg/kg if an acetylen-dinitrogen monoxide flame is used. The principle consists in the acidification of a test portion with hydrochloric acid, aspiration of the solution into an acetylene-dinitrogen monoxide flame or acetylene-air flame. In the latter case…
Liquid chemical products for industrial use — Determination of density at 20 degrees C
The principle of the specified method of reference consists in the determination of the mass of a volume of the substance at 20 °C which is contained in a pyknometer, and the determination of the capacity of pyknometer by measuring the mass of an adequate volume of water at 20 °C. Calculation of the density by division of the mass of substance by the capacity of pyknometer. - Replaces ISO…
