Iodine value

A small aliquot of oil is dissolved in a suitable solvent and reacted with an excess of iodine monochloride (Wij's iodine solution). The residual iodine, after reaction, is titrated against standard sodium thiosulphate using starch as an indicator.

Method used BS 684, Section 2.13
Units mg I2/g Oil
Significance of result
The iodine value is a measure of the unsaturation of an oil. The higher the iodine value the more double bonds are present, which consequently reflects the reactivity of the oil.
Notes Solid fats have low iodine values (typically <60).
Non drying liquid oils have iodine values of approx. 80-120.
Semi-drying oils have an iodine value in the range 120-150.
The iodine value of drying oils are normally greater than 150. Also known as the iodine number.
Tetst Tube and Flask