A new method for quantifying iodine in a starch-iodine matrix.

A rapid and sensitive method for quantifying iodine in intact starch granules using gas chromatography is described with detection limits as low as 0.2% (w/w) iodine in starch. Sample preparation includes NaBH(4) reduction of the various iodine species associated with starch to the colorless soluble iodide ion, followed by its quantitative derivatization to EtI using Et(3)O(+)BF4- in CH(2)Cl(2).