The use of ion-exchange filters for the determination of iodide in milk by X-ray fluorescence spectrometry.

Abstract An X-ray fluorescence spectrometric method has been developed for the quantitative determination of iodide in milk which makes use of anion-exchange filters for the isolation and concentration of iodide from the liquid samples. The milk is deproteinized with trichloroacetic acid, filtered then passed through an anion-exchange paper disc to remove the iodide. The disc is removed, dried then analysed by X-ray fluorescence spectrometry. Six samples, consisting of homogenized, 2% fat and skim milk were analysed and found to contain between 0.37–0.67 ppm iodide. Detection limits in milk were estimated to be 0.05 ppm.