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

Abstract

Energy-dispersive X-ray fluorescence (EDXRF) measurements using the monochromatic excitation of a Mo-K_α X-ray tube (17.44 keV) have been established for the direct determination of trace arsenic.A detection limit of 0.08μg g^-1 in light-element matrices was obtained, and the relative standard deviation for ten determinations of 2μg g^-1arsenic is 1.2%.The application of the proposed method to the arsenic limit test (Japanese Pharmacopoeia, Japanese Standards of Cosmetic Ingredients) was investigated.The recoveries of arsenic in various samples were satisfactory.Compared with the conventional arsenic limit test, the proposed method is much easier to operate because sample preparation is unnecessary;furthermore, the detection limit, reproducibility and recovery are higher.The EDXRF method is useful as a rapid substitute method (30 min) of the arsenic limit test.