Iodine Value – Method Validation

24 January, 2018 Posted by: ICNE

Iodine Value is the measure of unsaturation of an oil, fat or wax. Oils, fats and waxes contain hydrocarbon chains which can be saturated or unsaturated. A saturated compound contains only single bonds between carbon atoms. Unsaturated compounds contain double or triple bonds between carbon atoms. The higher the number of double or triple bonds in a molecule i.e. the higher the degree of unsaturation, the more reactive and therefore the less stable the molecule is. This means that with a higher unsaturation level, the more prone a compound is to oxidation and rancidification.

How Does the Iodine Value Test Work?

The iodine value is determined by measuring the amount (in grams) of iodine in a solution that is taken up by 100g of oil, fat or wax. In comparison to unsaturated molecules, saturated molecules are not very reactive with iodine, therefore the iodine is not taken up by the saturated oils. As unsaturated molecules are more reactive they can more readily react with the iodine. In the iodine value method, a solution of iodine bromide is allowed to react with the sample. This will allow any double bonds in the sample to react with the iodine. Potassium iodide is then added which reacts with any un-reacted iodine bromide solution to form molecular iodine. The iodine is then titrated with Sodium Thiosulphate with an indicator of starch solution, until a yellow colour is discharged. A calculation is then made to determine the Iodine Value.

Testing Iodine Value at ICNE

Here at ICNE, we have validated the European Pharmacopoeia 2.5.4 Iodine Value (Method A). We are able to use this method for any raw material that has a Ph. Eur. Monograph, and where one of the tests listed is Iodine Value, Method A.

Assessments are made in duplicate along with a control blank sample. If you require Iodine Value analysis of your raw materials, using the Ph. Eur. Iodine Value Method A, then contact ICNE today for a quote on 01253 737009 or info@icne.co.uk.