[Contribution of natural mineral water to the iodine supply of the population].

Most parts of Germany are iodine deficiency areas. Daily iodine intake may be increased by food with high iodine content. Therefore determination of iodine in different foodstuffs is of importance. Aim of our work was to develop a method for mineral waters. Besides, we wanted to find out to what extent natural mineral waters can contribute to the iodine supply of the population. The method is based on the reaction of the halogenids iodide and bromide with ethylene oxide in a sulfuric acid medium while converting into 2-iodo- and 2-bromoethanol. After extraction, the reaction products are determined by capillary gas chromatography with an electron capture detector. The method was modified for mineral waters. Single results were confirmed by ICP-MS. For mineral waters the limits of determination are 3 micrograms/L for iodide and 42 micrograms/L for bromide. The investigation of mineral waters from Hessen showed, that only few sources contain iodide in remarkable amounts. Therefore a considerable improvement of iodide intake is possible only with single mineral waters.