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Based on dissolution of a test sample in water. Distillation of the ammonia after displacement by an alkali solution. Absorption in an excess of standard volumetric sulphuric acid solution and back-titration with standard volumetric sodium hydroxide solution in the presence of methyl red/methylene blue mixed indicator. A typical distillation apparatus is shown in a figure.

Based on the conversion of nitrate into ammonia by means of Devarda's alloy in alkaline solution together with the liberation of ammonia from ammonium ions. Distillation of the ammonia from both reactions, absorption in an excess of standard volumetric sodium hydroxide solution in the presence of methyl red/methylene blue mixed indicator. A typical distillation apparatus is shown in a figure.

Applicable to products of which the Cu content is more than 0,1 mg/kg. The detection bases on the formation of a coloured complex of copper and of zinc dibenzyldithiocarbamate and photometric measurement at a wavelength of about 435 nm.

Specifies a reduced molybdosilicate spectrophotometric method for the determination of the soluble silica content of phosphoric acid for industrial use. The method can be used for the determination of 1 µg of soluble silica in the presence of 20 mg of phosphorus pentoxide. It is thus, for example, applicable to the determination of soluble silica contents greater than 30 mg/kg if the phosphoric…

The method is applicable to undyed wool in any form, for example loose fibre, sliver, yarn or fabric. It is also applicable to dyed wool when the amount of dye extracted during the test does not interfere with the determination of the end-point of titration. The determined value is expressed as a percentage by mass.

The method is applicable to all zinc types provided that their copper content is 0,01 % maximum. The determination is suitable for iron contents between 0,001 and 0,01 %. This standard specifies principle, reagents, apparatus, sampling, procedure, expression of results and test report.

Based on dissolution of a test sample in water, distillation of the ammonia after displacement by an alkali solution. Absorption in an excess of standard volumetric sulphuric acid solution and back-titration with standard volumetric sodium hydroxide solution in the presence of methyl red/methylene blue mixed indicator. A typical distillation apparatus is shown in a figure.

The method is applicable to Zn 99,5, Zn 98,5 and Zn 98 and is suitable for the determination of lead contents between 0,1 and 3 %. Specifies principle, reagents, apparatus, sampling, procedure, expression of results and test report.

The method is applicable to Zn 99,995, Zn 99,99 and Zn 99,95. Although these types of zinc do not normally contain any thallium or indium, these two elements, if present, can interfere in this determination. The method is suitable for the determination of lead and cadmium contents between 0,001 and 0,05 %.