Рентгенофлуоресцентное определение брома в донных отложениях озер для палеоклиматических исследований

Abstract

One of the signals of changing paleoclimate is the concentration of bromine which is increased in the warm periods and correlated with the content of organic matter in sediments. A conventional wavelength dispersive X-ray fluorescence analysis ( WDXRF ) and total reflection X-ray fluorescence analysis ( TXRF ) have been applied to study the bromine distributions in the sediments ofLakeBaikal andLakeKhara-Nur. In order to carry out WDXRF, the samples weighing about 200-300 mg with diameter of10 mm were pressed as tablets on the boric acid base; the bromine concentrations were calculated by the internal standard method with correction using fundamental parameters. For TXRF measurements the powdered sample weighing 20 mg was suspended in the surface-active solution of Triton X-100 and Ge solution was added for the internal standardization. The detection limits of bromine were 1 mg/kg and 0.4 mg/kg for WDXRF and TXRF respectively. It was shown that the results of the bromine determination obtained with different XRF techniques were comparable to each other and can be used for palaeoclimatic reconstruction. One of the main advantages of the offered WDXRF and TXRF techniques is the lack of necessity for the standard reference materials of sediments with certified content of bromine. Keywords: X-ray fluorescence analysis, XRF, TXRF, SRXRF, sediments, bromine, paleoclimate (Russian) DOI: http://dx.doi.org/10.15826/analitika.2015.19.4.008 G.V. Pashkova 1 *, E.V. Ivanov 2 ,T.S. Aisueva 2 , А . А . Shchetnikov 1 , Yu.N. Markova 2 , A.L. Finkelshtein 2 1 Institute of the Earth’s Crust, Siberian Branch of Russian Academy of Sciences, Irkutsk, Russian Federation 2 Vinogradov Institute of Geochemistry, Siberian Branch of Russian Academy of Sciences, Irkutsk , Russian Federation