Tincture of iodine recommended source of solely-nutritional iodine. Nutritional iodine is better supplied in the form of the less toxic iodide (see SSKI) or iodate salts, which the body can easily convert to thyroid hormone. Nevertheless, the iodide in tincture of iodine used as a water disinfectant does supply more than adequate nutritional iodine, perhaps 30 or more times the recommended daily allowance per liter or quart. Application of tincture or Lugol's to the skin also results in absorption and bioavailability of some moderate fraction of the iodine. Tincture of iodine Tincture of iodine, iodine tincture, or weak iodine solution is an antiseptic.
Iodine and iodate anions are often used for quantitative volumetric analysis, for example in iodometry and the iodine clock reaction (in which iodine also serves as a test for starch, forming a dark blue complex), and aqueous alkaline iodine solution is used in the iodoform test for methyl ketones. The iodine test for starch is still used to detect counterfeit banknotes printed on starch-containing paper. The spectra of the iodine molecule, I, consists of (not exclusively) tens of thousands of sharp spectral lines in the wavelength range 500-700 nm. It is therefore a commonly used wavelength reference (secondary standard). By measuring