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The principle is based on the conversion of the methanol present in a test portion to formaldehyde by oxidation with a solution of potassium permanganate in phosphoric acid. Reaction of the formaldehyde formed with Schiff reagent. Visual comparison of the colour obtained with the colours of standard colorimetric solutions containing known quantities of formaldehyde. - International Standards ISO…

The principle is based on distillation of a test portion in the presence of water, addition to the distillate of a saturated sodium chloride solution and measurement of the volume of insoluble hydrocarbons. A Hempel fractionating column with Liebig condenser is used for the distillation. - International Standards ISO 1388/1 to ISO 1377/12 cancel and replace ISO Recommendation R 1388-1970 of which…

The document also specifies the methods to be used for the determination of density at 20 °C, for the determination of dry residue after evaporation on a water bath, for the determination of water content, and for the measurement of colour. - International Standards ISO 1388/1 to 1388/12 cancel and replace ISO Recommendation R 1388-1970 of which they constitute a technical revision.

The method is applicable to products having acidities equal to or greater than 0.0008 % (m/m). The principle consists in the dilution of a test portion with carbon dioxide-free water, checking whether the test solution is alkaline or acid to phenolphthalein, and, if appropriate, determination of the acidity by titration with standard volumetric sodium hydroxide solution. The acidity is expressed…

The procedure consists in addition of water to a test portion, under specified conditions, and followed by examination vertically for any opalescence or turbidity against a black background with side illumination. International Standards ISO 756/1, ISO 756/2 ans ISO 756/3 cancel and replace ISO Recommendation R 756-1968 of which they constitute a technical revision.

The absorbance curve of an ethanolic solution of the oil in the wavelength range from 220 to 440 nm is plotted and from this the CD value is determined. The CD value is the measure of segment CD, expressed in absorbance units for the exact mass of test portion specified in the International Standard appropriate to the essential oil concerned. The determination of segment CD is described in detail.

The principle of the determination consists in reaction of the acetaldehyde present in a test portion with an excess of sodium hydrogen sulphite solution, and iodometric titration of the residual sodium hydrogen sulphite. The method is applicable to products having acetaldehyde monomer contents equal to or greater than 0,01 % (m/m). This International Standard as also been approved by the…

The principle consists in conversion of heavy metals, such as lead, copper and iron, to their sulphides by treatment with sodium sulphide in ammoniacal solution, and visual comparison of the colour produced with that of a standard lead solution similarly treated. The method detects only the heavy metals present in non-complex form. Using a test portion of 25 g, the method is applicable directly…

Gives general instructions and also specifies the methods to be used for the determination of dry residue after evaporation on a water bath, for the determination of the crystallizing point (temperature) of glacial acetic acid, for the determination of water content, for the measurement of colour and for the determination of arsenic content. The method is applicable to products having acedic acid…