Rapid analysis for the heavy metals limit test by energy-dispersive X-ray fluorescence analysis with monochromatic excitation

Abstract

Energy-dispersive X-ray fluorescence (EDXRF) measurements using three monochromatic excitations (W-L_β 9.7 keV, Mo-K_α: 17.4 keV and W-continuum: 40 keV) have been established for the direct determination of trace heavy metals in light-element matrices. The detection limits are 0.080.64μg g-¹ (Pb;0.25μg g^-1, mean value;0.35μg g^-1), ascertained for the 26 elements examined (VPb and Bi). The precisions were found to be within 1% R. S. D. at 20μg g^-1 for all of the elements. The application of this method to the heavy metals limit test (Japanese Pharmacopoeia, Japanese Standards of Cosmetic Ingredients) was investigated.The recoveries of Pb and heavy metals in various standard samples were satisfactory. Compared with the conventional heavy metals limit test, the proposed method is much easier to operate without sample preparation;furthermore, the detection limit, reproducibility and recovery are higher. The present EDXRF is useful as a rapid and simple substitute method(3060 min)of the heavy metals limit test.