RAPID-DETERMINATION OF TRACE PHOSPHORUS, SULFUR, CHLORINE, BROMINE AND IODINE BY ENERGY-DISPERSIVE X-RAY-FLUORESCENCE ANALYSIS WITH MONOCHROMATIC EXCITATIONS

A useful and rapid procedure is described for the determination of tra ce phosphorus, sulfur, chlorine, bromine, and iodine by means of an en ergy dispersive X-ray fluorescence spectrometer (EDXRF) with monochrom atic excitations. Using monochromatic excitations, the detection limit s for phosphorus, sulfur, chlorine (Cr-K alpha, 5.41 keV), bromine (Mo -K alpha, 17.44 keV), and iodine (W-continuum, 40 keV) were found to b e 4.6, 1.7, 0.7, 0.09 and 0.5 mu g g(-1), respectively. The relative s tandard deviations in five replicate measurements were 0.9 similar to 1.3%. The proposed method was applied to the direct determination of s ulfur in the NIST Residual Fuel Oil, and others. The results obtained by the proposed method were in good agreement with the certified value s. Bromine in a seawater sample, as well as iodine and bromine in a br ine sample were determined by the proposed method. The obtained result s were in good agreement with those obtained by ion chromatography.