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  • Author or Editor: R. Cesareo x
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Abstract  

A comparative study of radioactive X-ray fluorescence and neutron activation analysis using a low-intensity252Cf source has been carried out. X-ray fluorescence proved to be superior to NAA if ion-exchange preconcentration preceds the instrumental method, while less difference in the minimum detectable limit was found in direct analysis of aqueous solutions.

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Abstract  

The minimum detection limit of chemical elements attainable with X-ray fluorescence analysis induced by X or γ radioactive sources are evaluated. To this purpose, after a short review of the characteristics peculiar of XRF analysis systems, the contribution of the various physical processes which determine the background for thick or thin samples, under typical operational conditions, are discussed and theoretically evaluated. Furthermore the behaviour of minimum detection limits versus the atomic number of element to be detected is theoretically evaluated for typical matrices. Such results are compared with the experimental data obtained by means of simple portable units. Useful criteria are given in order to reach the best sensitivity.

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Abstract  

The present work shows a methodology for the application of EDXRF with a X-ray tube, in the analysis of elements in the following matrices: microalgae, marine algae, marine sediments and corals. Various methods were applied: one using a relative external standard, a fundamental parameters method, an absolute method based on elemental sensitivity, a method which used X-ray fluorescence excitation measured in the back side of the sample for low contents heavy elements determination and a TRXRF method. The thin layer samples were prepared using a plastic resin. The analyzed samples of marine algae, marine sediments and corals belong to a marine ecosystem from the North of Havana City, the most affected area by natural metereological phenomena and human impact.

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