SSH ISO 1388-7:1981

Etanol për përdorim industrial - Metodat e provës - Pjesa 7: Përcaktimi i përmbajtjes të metanolit (përmbajtjet e metanolit ndërmjet 0,01 dhe 0,20 % (V/V)) - Metoda fotometrike

Ethanol for industrial use — Methods of test — Part 7: Determination of methanol content (methanol contents between 0,01 and 0,20 % (V/V)) — Photometric method

Scope

The principle is based on the conversion of methanol present in a test portion to formaldehyde by oxidation. The oxidation is carried out with a solution of potassium permanganate in phosphoric acid. Reaction of the formaldehyde formed with chromotropic acid (4,5-dihydroxynaphthalene-2,7-disulphonic acid). Photometric measurement of the violet coloration obtained at a wavelength of about 570 nm. - International Standards ISO 1388/1 to ISO 1377/12 cancel and replace ISO Recommendation R 1388-1970 of which they constitute a technical revision.