Using Scattered Radiation Method in element analysis of sediments by total reflection X-ray fluorescence

Abstract

A technique for determining Al, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Rb, Sr and Ba in sediments by total reflection X-ray fluorescence (TXRF) was proposed. Sample preparation procedure consisting of suspending 20 mg of powdered sample in 2 ml of a 0.5% methylcellulose solution and depositing a volume 10 µL of a slurry on the reflector showed to be the most suitable. The sample preparation error did not exceed 10% for most analytes. In order to calculate the concentration of the elements, scattered radiation method was used where the analytical parameter was the ratio between the intensity of the analytical line and the intensity of the scattered incoherent radiation of the MoKα line. Using the intensity of the scattered incoherent radiation allowed taking into the account the variations in the surface density of the dried sample on the reflector. To control accuracy, certified “BIL-1” and “SGH-1” reference materials were used. It was shown that the scattered radiation method does not concede with the internal standard method widely used in TXRF and provides better results than the internal standard method in most cases. The TXRF results obtained for the sediment samples were compared to the results obtained by a conventional X-ray fluorescence spectrometer. It was shown that the changes in the element content along with the core depth obtained by both methods, were consistent and had a common tendency. Key words : X-ray fluorescence analysis, XRF, total reflection X-ray fluorescence, TXRF, sediments, methylcellulose, internal standard, scattered radiation method (Russian) DOI: http://dx.doi.org/10.15826/analitika.2018.22.2.004 G.V. Pashkova 1,2 , М . М . Mukhamedova 1,2 , Т .S. Aisueva 3 , А .L. Finkelshtein 1,3 , А . А . Shchetnikov 1,4 1 Institute of the Earth’s Crust, SB RAS, Lermontov st., 128, Irkutsk, 664033, Russian Federation 2 Irkutsk State University,1 K. Marx St., Irkutsk, 664003, Russian Federation 3 Vinogradov Institute of Geochemistry, SB RAS, Favorsky st., 1A, Irkutsk , 664033, Russian Federation 4 Irkutsk Scientific Center, SB RAS, Lermontov st., 134, Irkutsk, 664033, Russian Federation