EDXRF determination of impurities in potassium dihydrogenphosphate single crystals and raw materials

A fast and simple preconcentration procedure for recovering various cation impurities from potassium dihydrogenphosphate (KDP) single crystals and raw materials, followed by energy-dispersive X-ray fluorescence analysis (EDXRF), is described. The technique is based on the adsorption of metal 8-hydroxyquinoline complexes from aqueous solutions of KDP on activated carbon, separation of the concentrate on a Nuclepore filter and subsequent determination by EDXRF. To fix activated carbon powder on a filter surface, an amount of 1-hexadecanol is added to the KDP solution during the preconcentration procedure. The optimum conditions for the best recovery of the impurities were established. It was shown that a preconcentration factor of 100 can be achieved and the detection limit for a number of elements was down to 0.01 µg g−1. The relative standard deviations were 6–17% for element concentrations of 0.2 µg g−1. The method was successfully applied to the determination of Fe, Co, Cu, Ni, Zn, Mn, Ti and Bi in KDP single crystals and raw materials. Copyright © 2005 John Wiley & Sons, Ltd.