Essential oils (containing tertiary alcohols) — Estimation of free alcohols content by determination...
The estimation is carried out by acetylation of the essential oil by acetyl chloride and acetic anhydride, in the presence of dimethylaniline. The acetylated oil is isolated and dried and the ester value is determined. The free alcohols content is calculated taking into account the ester values of the same but non-acetylated essential oil. This method is applicable to essential oils containing an…
Is applicable to sweetened condensed milk of normal composition prepared from whole, partially skimmed or skimmed milk and sucrose only and containing no altered succrose. The principle consists in treating the sample with ammonia, neutralizing and clarifying by addition of zinc acetate and potassium hexacyanoferrate(II). This is following by filtration and determination of the optical rotation…
Aluminium and aluminium alloys — Determination of chromium — Spectrophotometric method using dipheny...
The method is applicable to chromium contents between 0,002 and 0,60 % (m/m). It may be extended to chromium contents of up to 1,5 % (m/m). Specifies principle, reagents, apparatus, sampling, procedure, expression of results and test report.
Potassium hydroxide for industrial use — Determination of calcium and magnesium contents — Flame ato...
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…
Phosphoric acid for industrial use (including foodstuffs) — Determination of calcium content — Flame...
Applicable to products having a Ca content of more than 50 mg/kg. Soluble SiO2 present in the solution at levels lower than 5 g/ml does not interfere. The principle consists in addition, to a hydrochloric acid solution of the test portion, of sodium ions to promote and stabilize the emission of calcium and of lanthanum ions to suppress the interference of aluminium. Specifies the aspiration of…
Paraformaldehyde for industrial use — Methods of test — Part 3: Determination of iron content — 2,2&...
Conversion of iron contained in a test sample to sulphate by treatment with hot sulphuric acid. Oxidation of the iron present in the solution by hydrogen peroxide and subsequently reduction of the iron(III) by hydroxylammonium chloride. Formation of the coloured complex iron(II)-2,2'bipyridyl in a buffered medium. Photometric measurement of the coloured complex at a wavelength of about 510…
The sample is dried at 105 to 110 °C in a stream of nitrogen and then pyrolysed under conditions in which the organic matter leaves an oxygen-free char. The volatile products, containing the organically bound oxygen and also water and carbon dioxide from any mineral matter, are decomposed with either pure carbon or platinized carbon to convert the oxygen to carbon monoxide. The carbon monoxide is…
Hydrochloric acid for industrial use — Determination of sulphate content — Barium sulphate gravimetr...
The method is applicable to products having sulphate contents equal to or greater than 0,1 % (m/m). The principle consists in precipitation of the sulphates contained in a test portion as barium sulphate in diluted hydrochloric acid medium. Separation of the precipitate obtained and ignition of the residue in an electric furnace, amintained at (800 +- 25 ) °C, and weighing. Replaces ISO…
Unalloyed copper containing not less than 99,90 % of copper — Determination of copper content — Elec...
The method is applicable to unalloyed coppers not containing elements providing insoluble residues in the electrolytic solution. Annex A gives test portions of test sample and of copper precipitate. Annex B describes a spectrophotometric method for the determination of residual copper in the electrolytic solution after deposition of copper on the cathode.
