Meat and meat products — Determination of nitrogen content (Reference method)
The method consists in digesting of a test portion with concentrated sulphuric acid, using copper(II) sulphate as a catalyst, to convert organic nitrogen to ammonia ions. Then alkalisation, distillation of the liberated ammonia into an excess of boric acid solution, titration with hydrochloric acid to determine the ammonia bound by the boric acid, and calculation of nitrogen content of the sample…
Fruit and vegetable products — Determination of soluble solids content — Refractometric method
The method is particularly applicable to thick products, to products containing suspendes matter and to products rich in sugars. If the products contain other dissolved substances, the results will be only approximate, nevertheless they may be considered conventionally as the soluble solids content. The principle consists in measuring of the refractive index of a test solution at 20 °C, using a…
Ammonium nitrate for industrial use — Determination of water content — Karl Fischer method
Describes a method applicable to products having water contents equal to or greater than 0,05 % (m/m). The principle of determination is based on the reaction of water with a solution of iodine and sulphur dioxide in a pyridine-methanol mixture (Karl Fischer reagent) which is standardized previously by titration of an exactly known mass of water. The end point of the reaction is then determined…
Sulphur for industrial use — Determination of chloride content — Photometric method
Is applicable to products having chloride contents, expressed as chlorine, greater than 2 mg/kg. The principle of determination consists in extracting the chlorides by boilling a test portion in aqueous 2-propanol, followed by a quantitative displacement of the thiocyanate ions of mercury(II) thiocynate by the chloride ions contained in an aliquot portion of the extraction solution, and reaction…
Sodium hexafluorosilicate for industrial use — Determination of iron content — 1,10 phenanthroline s...
Applicable to products having Fe contents between 0.0004 % (m/m) and 0.1 % (m/m). The residue from the determination of the loss of mass according to ISO 5444 is used to prepare the test sample. Decomposition of the hexafluorosilicate and elimination of silica by evaporation with hydrofluoric and sulphuric acids. Dissolution of the residue in hydrochloric acid and reduction of the iron(III) with…
Caseins and caseinates — Determination of water content (Reference method)
Is applicable to all types of caseins and caseinates. The principle consists in drying a test portion at 102 +/- 1 degree centigrade and weighing to determine the loss of mass which is expressed as a percentage by mass.
Sodium hexafluorosilicate for industrial use — Determination of phosphate content — Molybdovanadate ...
Applicable to products having contents, expressed as phosphorus pentoxide, of 0.005 % (m/m) to 0.05 % (m/m). The residue from the determination of the loss of mass according to ISO 5444 is used to prepare the test sample. Dissolution in dilute hydrochloric acid and nitric acid solutions. Formation of the yellow molybdovanadate and spectrophotometric measurement at a wavelength of about 420 nm.…
Applies to moist and air-dry pulp which does not contain any appreciable quantity of matter, other than water, volatile at the temperature specified for the drying, and is not applicable to the dry matter content of slush pulp or to the determination of the saleable mass of pulp lots.
