Sulphuric acid and oleum for industrial use — Determination of total nitrogen content — Titrimetric ...
The method is applicable to products having a total nitrogen content equal to or greater than 0.05 % (m/m). The principle consists in the conversion of the nitrogen present in a test portion to ammonia by means of nascent hydrogen. Distillation and absorption of the ammonia in an excess of standard volumetric sulphuric acid solution, and back-titration with a standard volumetric sodium hydroxide…
Surface active agents — Technical sodium primary alkylsulphates — Methods of analysis
Specifies the following methods of analysis for the substances to be tested: measurement of pH, determination of water content, determination of free alkalinity or free acidity, determination of total alkalinity, determination of matter extractable by light petroleum, determination of matter extractable by diethyl ether after acid hydrolysis (combined technical fatty alcohols), determination of…
Surface active agents — Technical sodium secondary alkylsulphates — Methods of analysis
Specifies the following methods of analysis for the substances to be tested: measurement of pH, determination of water content, determination of free alkalinity or free acidity, determination of total alkalinity, determination of matter extractable by light petroleum, determinition of the sodium alkylsulphates content, determination of sodium sulphate content, determination of sodium chloride…
Nitric acid for industrial use — Determination of nitrous compounds — Titrimetric method
Two cases are considered: content of nitrous compounds, expressed as HNO2, equal to or greater than 0,01 % (m/m) and content of nitrous compounds, expressed as HNO2, less than 0,01 % (m/m). The principle consists in oxidatiuon of the compounds present in a test portion by an excess of standard volumetric potassium permanganate solution. Addition of an excess of a standard volumetric iron(II)…
Urea for industrial use — Determination of nitrogen content — Titrimetric method after distillation
The procedure is based on the catalytic conversion of nitrogen present in a test portion to ammonia by heating in concentrated sulphuric acid solution. Distillation and absorption of the ammonia in an excess of standard volumetric sulphuric acid solution and back-titration with standard volumetric sodium hydroxide solution in the presence of an indicator. - Replaces ISO Recommendation R 1592-1970.
Specifies the following determinations for the substances to be tested: Measurement of pH, determination of water content, determination of free alkalinity or free acidity, determination of matter extractable by light petroleum, determination of sodium alkylarylsulphonates content, determination of sodium sulphite content, determination of sodium sulphate content, determination of sodium chloride…
Butter — Determination of water, solids-not-fat and fat contents on the same test portion (Reference...
Depending on the content to be estimated the method described uses three different steps for determination, i.e. drying of a known mass of butter at 102 +/- 2 degrees centigrade and weighing to determination the loss of mass, extraction of the fat from the dried butter with light petroleum or n-hexane and weighing of the residue, and calculation of the fat content by difference.
Ammonium hydrogen carbonate for industrial use (including foodstuffs) — Determination of arsenic con...
Applicable to products having As contents more than 0.2 mg/kg. The principle consists in reduction of the element to arsine in a solution of silver diethyldithiocarbamate in pyridine. Photometric measurement of the purplish- red colour produced by the colloidally dispersed silver, at the maximum of the absorption curve (wavelength approximately 540 nm).
Cryolite, natural and artificial — Conventional test for evaluation of free fluorides content
Applicable to products having contents of AlF3 of more than 0.15 % (m/m) or of NaF of more than 0.4 % (m/m). Covers sintering of a test portion with a known quantity of sodium fluoride in a muffle furnace at a temperature of (790 10) °C. Under these conditions, aluminium fluoride in excess of that required by the stoichiometric formula AlF3 .3NaF reacts to form cryolite; extraction of the ground…
Sodium fluoride for industrial use — Determination of carbonate content — Gravimetric method
Applicable to products having contents, expressed as Na2 CO3 , more than 0.02 % (m/m). Describes the release of the carbon dioxide from a test portion by acidification and heating. Entrainment of the carbon dioxide in a flow of air and absorption in weighed absorption tubes containing soda asbestos. Specifies the weighing of the absorption tubes to determine the quantity released.
