Fruits, vegetables and derived products — Qualitative method for the detection of sulphur dioxide
The method is applicable to products having contents of 2 mg or more per kilogram. It consists in acidification of a test portion and decolourizing by the liberated gas of a starch indicator paper previously coloured blue by a trace of iodine vapour.
Essential oils — Determination of 1,8-cineole content
The determination is carried out by measurement of the crystallization temperature of a mixture of essential oil and o-cresol. This temperature depends on the 1,8-cineole content of the essential oil. A table gives the 1,8-cineole content as a function of the crystallization temperature of the essential oil/o-cresol mixture.
Light metals and their alloys — Code of designation based on chemical symbols
The designations of metals and alloys shall be based on the chemical composition limits given in International Standards. International chemical symbols shall be used for the designation of the principal metal and the major alloying elements followed by numbers indicating the metal grade or the nominal alloy content.
The method is applicable to cereals and cereal products as well as to certain products containing less the 1 % of crude fibre. It consists in boiling with a mixture of acetic acid, nitric acid and trichloroacetic acid (after any necessary grinding and defatting). Then separation and washing of the insoluble residue on a filter crucible. Drying and weighing of the insoluble residue, and…
Soaps — Determination of content of ethanol-insoluble matter
The soap is dissolved in ethanol, filtrated and the undissolved residue is weighed. The constituents not dissolved correspond to the additives and foreign matter, of low solubility or insolubility in 95 % (V/V) ethanol, added to soaps and also to substances in all soap formulations, such as alkali carbonates and chlorides, borates, perborates, suphates, silicates, phosphates etc. It also may…
Light olefins for industrial use — Determination of ammonia — Photometric method
Covers a method applicable to products having ammonia contents greater than 0,25 mg/kg. Consists in absorbing the ammonia from a gaseous sample in sulphiric acid medium with the formation of ammonium sulphate and passing a current of nitrogen into the absorption liquid to remove hydrogen sulphide which would interfere. This is followed by formation in an alkaline medium of the indophenol complex…
Paraformaldehyde for industrial use — Methods of test — Determination of aldehyde content — Titrimet...
The method is applicable to solid paraformaldehyde of aldehyde contents in the range 67 % (m/m) to 97 % (m/m). The principle consists in the reaction of aldehyde present in a test portion with neutralized sodium sulphite solution. Titration of the liberated sodium hydroxide with sulphuric acid solution using thymolphthalein as indicator. - This document has also been approved by the IUPAC.
Fertilizers — Determination of ammoniacal nitrogen content — Titrimetric method after distillation
The method consists in distilling of the ammonia from an alkaline solution, absorbing in an excess of standard volumetric sulphuric acid solution and back-titrating with standard volumetric sodium hydroxide solution. It is applicable only in the absence of urea or its derivatives, of cyanamide and of organic nitrogenous compounds.
