Determination of iodide amounts in urine and water by isotope dilution analysis

Urinary iodide and iodine in drinking water were determined in 318 healthy children aged 0 to 18 yr living in Izmir and environmental rural and urban areas in the western part of Turkey. The method is based on substochiometri c isotope dilution analysis. Iodide was precipitated by substoichiometric a mounts of AgNO3. Iodide-131 was used as a tracer. Electrophoresis was perfo rmed to separate (AgI)-I-131 from excess I-131-. The (AgI)-I-131 zone was c ut Off the electrophoresis payer and counted with a NaI(T1) scintillation c ounter. Count rates were plotted versus added KI concentrations. The unknow n iodide amount was found by using these linear plots. Iodide concentration ranges were within 1.8 - 100.45 mu g/L in the analyzed drinking water samp les. The mean value was 44.14 +/- 17.33 mu g/L and the median was 58.08 mu g/L. Urinary iodide concentration ranges were 0.22 - 142.22 mu g/L. The med ian of the distribution was 37.71 mu g/L and the mean was 40.30 +/- 24.05 m u g/L. The results show that the examined area suffers moderate iodine defi ciency.