Insoluble impurities [Oil]

Substances in oil not dissolvable in organic solvent such as petroleum ether etc.

Iodine value [Oil]

Iodine value (IV) determines the level of carbon saturation. Higher Iodine value generally implies a lower solidifying temperature. IV is a measure of the total number of unsaturated double bonds present in an oil. Iodine value, or iodine number, is a measure of the total amount of unsaturated fatty acids in an oil and is a measure of the number of grams of iodine which will combine with 100 grams of the oil. A low iodine value implies a high degree of saturation. Of the various procedures available, the most widely used is the Wijs method