Peroxide Value Method Brief description: This method for peroxide value determination of lipids is based on the original International Dairy Federation standard method. The basic principal of the method is that ferrous(Fe2+) ions are oxidized to ferric(Fe3+) ions by peroxides. The ferric iron reacts with the colorless ammonium thiocyanate to yield ferric thiocyanate (magenta colored). A standard curve can be generated with different levels of ferric iron using ferric chloride. This IDF method was modified by Shantha & Decker for fats and oils. This method has been modified to use a different solvent (methanol:butanol) so that a lot of samples can be processed using disposable plastic cuvettes, it is also a scaled down version. If chloroform is used, you must use quartz or glass cuvettes. Also, chloroform stabilized with amylene cannot be used. This method is more sensitive and uses less sample than the AOCS standard method, but is subject to a little more variation due to the small amount of sample used.