Zinc alloys — Complexometric determination of magnesium
The method is applicable to zinc alloys given in ISO 301 and to die castings made from these alloys. It is suitable for the determination of magnesium contents between 0,01 und 0,1 %. Specifies principle, reagents, apparatus, sampling expression of results, procedure and test report.
Potassium sulphate for industrial use — Determination of potassium content — Gravimetric method as p...
Dissolution of a test portion taken from the laboratory sample, previosly ground and sifted. Addition of formaldehyde to transform any ammonium ions present into hexamethylenetetramine and of the disodium salt of ethylenediamin tetra-acetic acid to complex any extraneous cations present which could cause excessive errors. These additions have no detrimental effect on the precision or…
Potassium sulphate for industrial use — Determination of sulphate content — Barium sulphate gravimet...
The principle consists in dissolution of a test portion and precipitation of the sulphate ions by barium chloride in boiling acid medium. Filtration, washing and ignition of the precipitate. Weighing the barium sulphate.
Potassium sulphate for industrial use — Determination of chloride content — Mercurimetric method
The principle of the analysis consists in dissolution of a test portion and addition, in a dilute acid medium, of mercuric salts which, with the chloride ions, form soluble and only slightly ionized mercury(II) chloride. Indication of the completion of the reaction by the appearance of a violet coloration due to the reaction between the excess of mercury(II) ions and the diphenylcarbazone used as…
Ammonium hydrogen carbonate for industrial use (including foodstuffs) — Determination of ammoniacal ...
Specifies a titrimetric method consisting in distillation of the ammonia after displacement by an alkaline solution; absorption in an excess of standard volumetric sulphuric acid solution and back-titration with standard volumetric sodium hydroxide solution in the presence of an indicator. The absorption of the ammonia may also be carried out in an excess of boric acid solution. The titration, in…
Meat and meat products — Determination of total fat content
The method consists in boiling of a test portion with hydrochloric acid to free the occluded and bound lipid fractions, filtrating of the resulting mass, drying, and extracting with n-hexane or light petroleum, of the fat retained on the filter.
Potassium hydroxide for industrial use — Determination of iron content — 1,10- Phenanthroline photom...
Describes a method that is more sensitive and more widely used than the 2,2'-bipyridyl method. It is applicable to products having iron contents equal to or greater than 0.3 mg/kg. The principle is based on the reduction of iron(III) by hydroxylammonium chloride, formation of a iron(II)/1,10-phenanthroline complex in a buffered system. Photometric measurement of the coloured complex at a…
