Determination of iodide in nutritional beverage products using an ion selective electrode.

An ion selective electrode procedure is described for the precise, accurate determination of iodide at the sub-ppm level in a variety of nutritional beverages. The relative standard deviation of the analysis is 1--4%; recoveries range from 90 to 120%. Comparison with results from neutron activation analysis and the traditional Sandell-Kolthoff procedure shows that the ion selective electrode procedure is free of determine error and that dry ashing of samples can lead to low results.