Reference number
ISO 787-4:1981
ISO 787-4:1981
© ISO 2024
International Standard
ISO 787-4:1981
General methods of test for pigments and extenders — Part 4: Determination of acidity or alkalinity of the aqueous extract
Edition 1
1981-09
1981-09
ISO 787-4:1981
5080
Published
(Edition 1, 1981)
This publication was last reviewed and confirmed in 2024.
Therefore this version remains current.
Abstract
The principle of the method consists in the hot extraction of the material by following the procedure specified in ISO 787/3, to the stage of obtaining a perfectly clear filtrate. The determination is carried out with indicator solution (method A). If the solution with the methyl red indicator is yellow (alkaline), titrate it with the hydrochloric acid solution to an orange end-point; if the solution with the methyl red indicator is red (acid), titrate it with the sodium or potassium hydroxide solution to an orange end-point. The other method (method B) is the potentiometric determination. Take 100 ml of the test solution, insert the electrodes of the pH measuring device and read the pH value.
General information
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Status: PublishedPublication date: 1981-09Stage: International Standard confirmed [90.93]
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Edition: 1Number of pages: 2
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Technical Committee :ISO/TC 256ICS :87.060.10
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