The determination consists in slow and progressive cooling of the essential oil and observation of the variations in temperature as the oil passes from the liquid to the solid state. The apparatur for determination of freezing point consists of a wide-mouthed container of about 500 ml capacity, provided with a bored cork or rubber stopper into which a stout-walled test tube is inserted. Another…
Aluminium oxide primarily used for the production of aluminium — Determination of boron content — Cu...
Applicable to products having boron oxide contents of more than 0.0006 % (m/m). With sufficiently sensitive apparatus, the lower limit of application may be extended to 0.00008 % (m/m). The test portion is dissolved in phosphoric acid. Separation of the boron by distillation as methyl borate. Formation of a red coloured complex between the boron and the curcumin reagent at pH 7.…
Aluminium oxide primarily used for the production of aluminium — Determination of fluorine content —...
Applicable to products having F contents of more than 0.003 % (m/m). Dissolution of a test portion by attack by sulphuric acid under pressure. Separation of the fluorine by distillation at a temperature of (150 1) °C by sulphuric acid. The distillation is carried out by the method described in ISO 1693. Formation of a blue coloured complex between fluorine and alizarin complexone/lanthanum…
Aluminium oxide primarily used for the production of aluminium — Determination of phosphorus content...
Applicable to products having phosphorus contents of more than 0.0005 % (m/m). Preparation of a solution from a test portion by alkaline fusion either with a mixture of sodium carbonate and borid or of sodium carbonate and sodium tetraborate. Dissolution of the cooled molten mass in nitric acid and adjustment of an appropriate aliquot portion to pH 2. Formation of a phosphomolybdic complex and…
Cryolite, natural and artificial — Determination of aluminium content — Atomic absorption method
Applicable to products having a normal composition for which the molar ratio NaF/AlF3 is equal to about 3. Dissolution of a test portion in concentrated suphuric acid and elimination of hydrogen fluoride. Treatment with hydrochloric acid and water. Atomization of the solution into an acetylene measurement of the absorption of the 309.3 nm line emitted by an aluminium hollow cathode lamp. Has also…
Acetaldehyde for industrial use — Determination of iron content — 2,2'- Bipyridyl photometric m...
The principle consists in the evaporation to dryness of a test portion and dissolution of the residue in hydrochloric acid. Reduction of iron(III) by means of hydroxylammonium chloride. Formation of the iron(II)- 2,2'-dipyridyl complex. Photometric measurement of the coloured complex at a wavelength of about 522 nm. Specifies the use of a spectrophotometer or photoelectric absorptionmeter.…
General method for the determination of arsenic — Silver diethyldithiocarbamate photometric method
Applicable to determining the quantities contained either in all the test solution or in the aliquot portion of between 1 g and 20 g that is taken for the determination. The principle bases on the reduction of the arsenic by zinc in a hydrochloric acid medium with the formation of arsine; absorption of the arsine in a solution of silver diethyldithiocarbamate in pyridine. Photometric measurement…
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…
Sodium hydrogen carbonate for industrial use — Determination of iron content — 1,10- Phenanthroline ...
The method is applicable to products having a content equal to or greater than 0,1 mg/kg. The principle concists in reduction of the iron(III) by hydroxylammoniumchloride. Formation of a iron(II)-1,10-phennanthroline complex in a buffered solution. Photometric measurement of the coloured complex at a wavelength of about 510 nm.
Aluminium fluoride for industrial use — Determination of iron content — 1,10- Phenanthroline photome...
The method is applicable to products having a content greater than 0,020 %. The principle consists in dissolution of a test portion by either alkaline or acid fusion. Reduction of the iron(III) by hydroxylammonium chloride. Formation of the iro(II)-1, 10-phenanthroline complex in a buffered medium (pH value between 3,5 and 4,2) Photometric measurement of the coloured complex at a wavelength of…
