Simple method of determination of iodide at microgram/L level in potable water with preliminary preconcentration by energy dispersive X-ray fluorescence spectrometry.

A simple method for iodide determination in potable water with preliminary preconcentration has been worked out. Iodide was precipitated as palladium (II) iodide on elemental palladium as a carrier, which was obtained by reduction of Pd(II) with sodium thiosulfate. Ammonium chloropalladite was used as a reagent. The volume of water taken for analysis was between 100 and 500 cm3. The precipitate was filtered through a membrane filter, air-dried and directly analyzed by the energy-dispersive x-ray fluorescence (EDXRF) method. 241Am radioisotope was used as a source of exciting radiation. The precision of the method was 7% for iodide mass per filter equal to 2 micrograms. The detection limit amounted to 0.45 microgram of iodide per filter.