1991 Volume 77 Issue 6 Pages 848-855
In the accurate analysis of the superconductor Tl2Ba2CanCun+1Ox -Hereafter, superconductor composition is written as (2223), when n=2- by X-ray fluorescence spectrometry, the microdroplet analysis technique combined with the fundamental parameter method has been found to be suitable because of the following reasons. The superconductor contains both poisonous and high-temperature-volatile thallium, and has few or no available standards. By this combined method, we determined components in superconductors (2223) and (2212), and obtained the results below.
1) Specimens were prepared by dissolving 1 g of sample with 10 ml of nitric acid (1+1), followed by dropping the solution onto formed filter papers asa much oxides as 0.353 mg/ cm2.
2) Standards were prepared via the same sample solution process as specimens, from the samples of known compositions and analogous matrices.
3) In addition, by adopting the homogeneous mixture of nitrates and the filter as a model for both specimens and standards, Tl2O3, BaO, CaO, and CuO in superconductors were determined with the respective accuracies σd's (differences from wet-chemical values) of 0.70 wt%, 1.06 wt%, 0.17 wt%, and 0.29 wt% in the case of (2223), and of 0.53 wt%, 0.73 wt%, 0.14 wt%, and 0.19 wt% in the case of (2212), which were fairly good.
4) Absorption enhancement effects for TlLα1, BaKα, CaKα, and CuKα under the present analytical conditions were calculated. However, they were recognized only in the case of CaKα and CuKα.