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
NORMA vydána dne 1.11.1981
Označení normy: ISO 1388-7:1981
Datum vydání normy: 1.11.1981
Počet stran: 4
Přibližná hmotnost: 12 g (0.03 liber)
Země: Mezinárodní technická norma
Kategorie: Technické normy ISO
Description / Abstract: 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.