Standard-addition procedure for the determination of traces of lead in solid samples by x-ray fluorescence spectrometry.

A standard-addition procedure for analysis of powdered solid samples by energy-dispersive X-ray fluorescence is described. Different amounts of the element to be determined are added to 4-6 specimens of the unknown sample. The spiked samples are prepared by mixing the powdered sample with an aqueous standard solution and drying the mixture. Homogeneously spiked samples are thus obtained with analyte and spike concentrations at the ppm level. The procedure has been investigated theoretically, and it is found suitable for the quantitative determination of lead at the ppm level. The accuracy of the technique for traces of lead has been tested on solid reference materials for the determination of lead. The quantitative results obtained compare well with those found by potentiometric stripping analysis.