The present application is directed to the use of electrophoresis with UV detection in the determination of iodine nutritional status in human biological specimens, specifically for monitoring iodine deficiency/inadequacy in large-scale epidemiological studies. In particular, the present application is directed to a method for determining iodide and iodide uptake inhibitors in a human biological sample when using sample self-stacking with capillary electrophoresis and UV detection.