Preconcentration of Strontium and Barium by Coprecipitation with Organic Collectors and Their Determination by X-Ray Fluorescence

Preconcentration of strontium and barium as complexes with 11 organic reagents by coprecipitation with organic co-precipitants for their subsequent determination by X-ray fluorescence spectrometry is studied. The most effective systems turned out to be those included reagents from bisazosubstituted chromotropic acids, nitchromazo and chlorophosphonazo III. Complexes of these metals are virtually quantitatively coprecipitated as pairs with cations of the brilliant green dye, of the collector is an associate of an excess of the analytical reagent with cations of this dye. It is shown that the additional use of polyvinyl butyral as an indifferent co-precipitant ensures not only the almost complete extraction of these elements from solutions, but also the preparation of emitter concentrates suitable for X-ray fluorescence measurements using the standard-background technique. High efficiency allows, under optimal conditions, the achievement of very low limits of detection (IUPAC): 0.03 μg/mL Sr and 0.19 μg/mL Ba, even in working with small samples (by volume).