MT 31 - Free acidity or alkalinity
Content Handbook F
Outline of method
The acidity or alkalinity is determined by titration with standard acid or alkali, in the presence of methyl red. Where this is impracticable, the end point is determined electrometrically.
31.1 Methyl red indicator method
31.2 Electrometric procedure
The method is suitable for determining free acidity or alkalinity in technical or formulated pesticides. It does not allow the etermination of acids or alkalis which are insoluble in acetone-water mixtures.